merge.c 86.3 KB
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/*
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 * Copyright (C) the libgit2 contributors. All rights reserved.
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 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */

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#include "merge.h"

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#include "posix.h"
#include "buffer.h"
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#include "repository.h"
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#include "revwalk.h"
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#include "commit_list.h"
#include "path.h"
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#include "refs.h"
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#include "object.h"
#include "iterator.h"
#include "refs.h"
#include "diff.h"
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#include "diff_generate.h"
#include "diff_tform.h"
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#include "checkout.h"
#include "tree.h"
#include "blob.h"
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#include "oid.h"
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#include "index.h"
#include "filebuf.h"
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#include "config.h"
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#include "oidarray.h"
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#include "annotated_commit.h"
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#include "commit.h"
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#include "oidarray.h"
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#include "merge_driver.h"
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#include "oidmap.h"
#include "array.h"
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#include "git2/types.h"
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#include "git2/repository.h"
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#include "git2/object.h"
#include "git2/commit.h"
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#include "git2/merge.h"
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#include "git2/refs.h"
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#include "git2/reset.h"
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#include "git2/checkout.h"
#include "git2/signature.h"
#include "git2/config.h"
#include "git2/tree.h"
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#include "git2/oidarray.h"
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#include "git2/annotated_commit.h"
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#include "git2/sys/index.h"
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#include "git2/sys/hashsig.h"
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#define GIT_MERGE_INDEX_ENTRY_EXISTS(X)	((X).mode != 0)
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#define GIT_MERGE_INDEX_ENTRY_ISFILE(X) S_ISREG((X).mode)
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typedef enum {
	TREE_IDX_ANCESTOR = 0,
	TREE_IDX_OURS = 1,
	TREE_IDX_THEIRS = 2
} merge_tree_index_t;

/* Tracks D/F conflicts */
struct merge_diff_df_data {
	const char *df_path;
	const char *prev_path;
	git_merge_diff *prev_conflict;
};

/* Merge base computation */

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int merge_bases_many(git_commit_list **out, git_revwalk **walk_out, git_repository *repo, size_t length, const git_oid input_array[])
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{
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	git_revwalk *walk = NULL;
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	git_vector list;
	git_commit_list *result = NULL;
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	git_commit_list_node *commit;
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	int error = -1;
	unsigned int i;

	if (length < 2) {
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		giterr_set(GITERR_INVALID, "at least two commits are required to find an ancestor");
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		return -1;
	}

	if (git_vector_init(&list, length - 1, NULL) < 0)
		return -1;

	if (git_revwalk_new(&walk, repo) < 0)
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		goto on_error;
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	for (i = 1; i < length; i++) {
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		commit = git_revwalk__commit_lookup(walk, &input_array[i]);
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		if (commit == NULL)
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			goto on_error;
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		git_vector_insert(&list, commit);
	}

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	commit = git_revwalk__commit_lookup(walk, &input_array[0]);
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	if (commit == NULL)
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		goto on_error;
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	if (git_merge__bases_many(&result, walk, commit, &list) < 0)
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		goto on_error;
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	if (!result) {
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		giterr_set(GITERR_MERGE, "no merge base found");
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		error = GIT_ENOTFOUND;
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		goto on_error;
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	}

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	*out = result;
	*walk_out = walk;
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	git_vector_free(&list);
	return 0;
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on_error:
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	git_vector_free(&list);
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	git_revwalk_free(walk);
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	return error;
}

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int git_merge_base_many(git_oid *out, git_repository *repo, size_t length, const git_oid input_array[])
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{
	git_revwalk *walk;
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	git_commit_list *result = NULL;
	int error = 0;
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	assert(out && repo && input_array);

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	if ((error = merge_bases_many(&result, &walk, repo, length, input_array)) < 0)
		return error;
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	git_oid_cpy(out, &result->item->oid);
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	git_commit_list_free(&result);
	git_revwalk_free(walk);
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	return 0;
}
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int git_merge_bases_many(git_oidarray *out, git_repository *repo, size_t length, const git_oid input_array[])
{
	git_revwalk *walk;
	git_commit_list *list, *result = NULL;
	int error = 0;
	git_array_oid_t array;
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	assert(out && repo && input_array);
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	if ((error = merge_bases_many(&result, &walk, repo, length, input_array)) < 0)
		return error;
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	git_array_init(array);

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	list = result;
	while (list) {
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		git_oid *id = git_array_alloc(array);
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		if (id == NULL) {
			error = -1;
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			goto cleanup;
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		}
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		git_oid_cpy(id, &list->item->oid);
		list = list->next;
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	}

	git_oidarray__from_array(out, &array);

cleanup:
	git_commit_list_free(&result);
	git_revwalk_free(walk);
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	return error;
}

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int git_merge_base_octopus(git_oid *out, git_repository *repo, size_t length, const git_oid input_array[])
{
	git_oid result;
	unsigned int i;
	int error = -1;

	assert(out && repo && input_array);

	if (length < 2) {
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		giterr_set(GITERR_INVALID, "at least two commits are required to find an ancestor");
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		return -1;
	}

	result = input_array[0];
	for (i = 1; i < length; i++) {
		error = git_merge_base(&result, repo, &result, &input_array[i]);
		if (error < 0)
			return error;
	}

	*out = result;

	return 0;
}

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static int merge_bases(git_commit_list **out, git_revwalk **walk_out, git_repository *repo, const git_oid *one, const git_oid *two)
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{
	git_revwalk *walk;
	git_vector list;
	git_commit_list *result = NULL;
	git_commit_list_node *commit;
	void *contents[1];

	if (git_revwalk_new(&walk, repo) < 0)
		return -1;

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	commit = git_revwalk__commit_lookup(walk, two);
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	if (commit == NULL)
		goto on_error;

	/* This is just one value, so we can do it on the stack */
	memset(&list, 0x0, sizeof(git_vector));
	contents[0] = commit;
	list.length = 1;
	list.contents = contents;

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	commit = git_revwalk__commit_lookup(walk, one);
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	if (commit == NULL)
		goto on_error;

	if (git_merge__bases_many(&result, walk, commit, &list) < 0)
		goto on_error;

	if (!result) {
		git_revwalk_free(walk);
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		giterr_set(GITERR_MERGE, "no merge base found");
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		return GIT_ENOTFOUND;
	}

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	*out = result;
	*walk_out = walk;

	return 0;

on_error:
	git_revwalk_free(walk);
	return -1;

}

int git_merge_base(git_oid *out, git_repository *repo, const git_oid *one, const git_oid *two)
{
	int error;
	git_revwalk *walk;
	git_commit_list *result;

	if ((error = merge_bases(&result, &walk, repo, one, two)) < 0)
		return error;

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	git_oid_cpy(out, &result->item->oid);
	git_commit_list_free(&result);
	git_revwalk_free(walk);

	return 0;
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}

int git_merge_bases(git_oidarray *out, git_repository *repo, const git_oid *one, const git_oid *two)
{
	int error;
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	git_revwalk *walk;
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	git_commit_list *result, *list;
	git_array_oid_t array;

	git_array_init(array);

	if ((error = merge_bases(&result, &walk, repo, one, two)) < 0)
		return error;

	list = result;
	while (list) {
		git_oid *id = git_array_alloc(array);
		if (id == NULL)
			goto on_error;

		git_oid_cpy(id, &list->item->oid);
		list = list->next;
	}

	git_oidarray__from_array(out, &array);
	git_commit_list_free(&result);
	git_revwalk_free(walk);

	return 0;
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on_error:
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	git_commit_list_free(&result);
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	git_revwalk_free(walk);
	return -1;
}

static int interesting(git_pqueue *list)
{
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	size_t i;

	for (i = 0; i < git_pqueue_size(list); i++) {
		git_commit_list_node *commit = git_pqueue_get(list, i);
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		if ((commit->flags & STALE) == 0)
			return 1;
	}

	return 0;
}

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static void clear_commit_marks_1(git_commit_list **plist,
		git_commit_list_node *commit, unsigned int mark)
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{
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	while (commit) {
		unsigned int i;
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		if (!(mark & commit->flags))
			return;

		commit->flags &= ~mark;

		for (i = 1; i < commit->out_degree; i++) {
			git_commit_list_node *p = commit->parents[i];
			git_commit_list_insert(p, plist);
		}

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		commit = commit->out_degree ? commit->parents[0] : NULL;
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	}
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}
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static void clear_commit_marks_many(git_vector *commits, unsigned int mark)
{
	git_commit_list *list = NULL;
	git_commit_list_node *c;
	unsigned int i;

	git_vector_foreach(commits, i, c) {
		git_commit_list_insert(c, &list);
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	}

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	while (list)
		clear_commit_marks_1(&list, git_commit_list_pop(&list), mark);
}
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static void clear_commit_marks(git_commit_list_node *commit, unsigned int mark)
{
	git_commit_list *list = NULL;
	git_commit_list_insert(commit, &list);
	while (list)
		clear_commit_marks_1(&list, git_commit_list_pop(&list), mark);
}

static int paint_down_to_common(
	git_commit_list **out, git_revwalk *walk, git_commit_list_node *one, git_vector *twos)
{
	git_pqueue list;
	git_commit_list *result = NULL;
	git_commit_list_node *two;

	int error;
	unsigned int i;

	if (git_pqueue_init(&list, 0, twos->length * 2, git_commit_list_time_cmp) < 0)
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		return -1;
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	one->flags |= PARENT1;
	if (git_pqueue_insert(&list, one) < 0)
		return -1;

	git_vector_foreach(twos, i, two) {
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		if (git_commit_list_parse(walk, two) < 0)
			return -1;

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		two->flags |= PARENT2;
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		if (git_pqueue_insert(&list, two) < 0)
			return -1;
	}

	/* as long as there are non-STALE commits */
	while (interesting(&list)) {
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		git_commit_list_node *commit = git_pqueue_pop(&list);
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		int flags;

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		if (commit == NULL)
			break;
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		flags = commit->flags & (PARENT1 | PARENT2 | STALE);
		if (flags == (PARENT1 | PARENT2)) {
			if (!(commit->flags & RESULT)) {
				commit->flags |= RESULT;
				if (git_commit_list_insert(commit, &result) == NULL)
					return -1;
			}
			/* we mark the parents of a merge stale */
			flags |= STALE;
		}

		for (i = 0; i < commit->out_degree; i++) {
			git_commit_list_node *p = commit->parents[i];
			if ((p->flags & flags) == flags)
				continue;

			if ((error = git_commit_list_parse(walk, p)) < 0)
				return error;

			p->flags |= flags;
			if (git_pqueue_insert(&list, p) < 0)
				return -1;
		}
	}

	git_pqueue_free(&list);
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	*out = result;
	return 0;
}

static int remove_redundant(git_revwalk *walk, git_vector *commits)
{
	git_vector work = GIT_VECTOR_INIT;
	unsigned char *redundant;
	unsigned int *filled_index;
	unsigned int i, j;
	int error = 0;

	redundant = git__calloc(commits->length, 1);
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	GITERR_CHECK_ALLOC(redundant);
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	filled_index = git__calloc((commits->length - 1), sizeof(unsigned int));
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	GITERR_CHECK_ALLOC(filled_index);
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	for (i = 0; i < commits->length; ++i) {
		if ((error = git_commit_list_parse(walk, commits->contents[i])) < 0)
			goto done;
	}

	for (i = 0; i < commits->length; ++i) {
		git_commit_list *common = NULL;
		git_commit_list_node *commit = commits->contents[i];

		if (redundant[i])
			continue;

		git_vector_clear(&work);

		for (j = 0; j < commits->length; j++) {
			if (i == j || redundant[j])
				continue;

			filled_index[work.length] = j;
			if ((error = git_vector_insert(&work, commits->contents[j])) < 0)
				goto done;
		}

		error = paint_down_to_common(&common, walk, commit, &work);
		if (error < 0)
			goto done;

		if (commit->flags & PARENT2)
			redundant[i] = 1;

		for (j = 0; j < work.length; j++) {
			git_commit_list_node *w = work.contents[j];
			if (w->flags & PARENT1)
				redundant[filled_index[j]] = 1;
		}

		clear_commit_marks(commit, ALL_FLAGS);
		clear_commit_marks_many(&work, ALL_FLAGS);

		git_commit_list_free(&common);
	}

	for (i = 0; i < commits->length; ++i) {
		if (redundant[i])
			commits->contents[i] = NULL;
	}

done:
	git__free(redundant);
	git__free(filled_index);
	git_vector_free(&work);
	return error;
}

int git_merge__bases_many(git_commit_list **out, git_revwalk *walk, git_commit_list_node *one, git_vector *twos)
{
	int error;
	unsigned int i;
	git_commit_list_node *two;
	git_commit_list *result = NULL, *tmp = NULL;

	/* If there's only the one commit, there can be no merge bases */
	if (twos->length == 0) {
		*out = NULL;
		return 0;
	}

	/* if the commit is repeated, we have a our merge base already */
	git_vector_foreach(twos, i, two) {
		if (one == two)
			return git_commit_list_insert(one, out) ? 0 : -1;
	}

	if (git_commit_list_parse(walk, one) < 0)
		return -1;

	error = paint_down_to_common(&result, walk, one, twos);
	if (error < 0)
		return error;
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	/* filter out any stale commits in the results */
	tmp = result;
	result = NULL;

	while (tmp) {
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		git_commit_list_node *c = git_commit_list_pop(&tmp);
		if (!(c->flags & STALE))
			if (git_commit_list_insert_by_date(c, &result) == NULL)
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				return -1;
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	}

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	/*
	 * more than one merge base -- see if there are redundant merge
	 * bases and remove them
	 */
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	if (result && result->next) {
		git_vector redundant = GIT_VECTOR_INIT;

		while (result)
			git_vector_insert(&redundant, git_commit_list_pop(&result));

		clear_commit_marks(one, ALL_FLAGS);
		clear_commit_marks_many(twos, ALL_FLAGS);

		if ((error = remove_redundant(walk, &redundant)) < 0) {
			git_vector_free(&redundant);
			return error;
		}

		git_vector_foreach(&redundant, i, two) {
			if (two != NULL)
				git_commit_list_insert_by_date(two, &result);
		}
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		git_vector_free(&redundant);
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	}

	*out = result;
	return 0;
}
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int git_repository_mergehead_foreach(
	git_repository *repo,
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	git_repository_mergehead_foreach_cb cb,
	void *payload)
{
	git_buf merge_head_path = GIT_BUF_INIT, merge_head_file = GIT_BUF_INIT;
	char *buffer, *line;
	size_t line_num = 1;
	git_oid oid;
	int error = 0;

	assert(repo && cb);

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	if ((error = git_buf_joinpath(&merge_head_path, repo->gitdir,
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		GIT_MERGE_HEAD_FILE)) < 0)
		return error;

	if ((error = git_futils_readbuffer(&merge_head_file,
		git_buf_cstr(&merge_head_path))) < 0)
		goto cleanup;

	buffer = merge_head_file.ptr;

	while ((line = git__strsep(&buffer, "\n")) != NULL) {
		if (strlen(line) != GIT_OID_HEXSZ) {
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			giterr_set(GITERR_INVALID, "unable to parse OID - invalid length");
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			error = -1;
			goto cleanup;
		}

		if ((error = git_oid_fromstr(&oid, line)) < 0)
			goto cleanup;

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		if ((error = cb(&oid, payload)) != 0) {
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			giterr_set_after_callback(error);
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			goto cleanup;
		}

		++line_num;
	}

	if (*buffer) {
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		giterr_set(GITERR_MERGE, "no EOL at line %"PRIuZ, line_num);
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		error = -1;
		goto cleanup;
	}

cleanup:
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	git_buf_dispose(&merge_head_path);
	git_buf_dispose(&merge_head_file);
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	return error;
}
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GIT_INLINE(int) index_entry_cmp(const git_index_entry *a, const git_index_entry *b)
{
	int value = 0;

	if (a->path == NULL)
		return (b->path == NULL) ? 0 : 1;

	if ((value = a->mode - b->mode) == 0 &&
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		(value = git_oid__cmp(&a->id, &b->id)) == 0)
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		value = strcmp(a->path, b->path);

	return value;
}

/* Conflict resolution */

static int merge_conflict_resolve_trivial(
	int *resolved,
	git_merge_diff_list *diff_list,
	const git_merge_diff *conflict)
{
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	int ours_empty, theirs_empty;
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	int ours_changed, theirs_changed, ours_theirs_differ;
	git_index_entry const *result = NULL;
	int error = 0;

	assert(resolved && diff_list && conflict);

	*resolved = 0;

	if (conflict->type == GIT_MERGE_DIFF_DIRECTORY_FILE ||
		conflict->type == GIT_MERGE_DIFF_RENAMED_ADDED)
		return 0;
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	if (conflict->our_status == GIT_DELTA_RENAMED ||
		conflict->their_status == GIT_DELTA_RENAMED)
		return 0;

	ours_empty = !GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry);
	theirs_empty = !GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry);
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	ours_changed = (conflict->our_status != GIT_DELTA_UNMODIFIED);
	theirs_changed = (conflict->their_status != GIT_DELTA_UNMODIFIED);
	ours_theirs_differ = ours_changed && theirs_changed &&
		index_entry_cmp(&conflict->our_entry, &conflict->their_entry);

	/*
	 * Note: with only one ancestor, some cases are not distinct:
	 *
	 * 16: ancest:anc1/anc2, head:anc1, remote:anc2 = result:no merge
	 * 3: ancest:(empty)^, head:head, remote:(empty) = result:no merge
	 * 2: ancest:(empty)^, head:(empty), remote:remote = result:no merge
	 *
	 * Note that the two cases that take D/F conflicts into account
	 * specifically do not need to be explicitly tested, as D/F conflicts
	 * would fail the *empty* test:
	 *
	 * 3ALT: ancest:(empty)+, head:head, remote:*empty* = result:head
	 * 2ALT: ancest:(empty)+, head:*empty*, remote:remote = result:remote
	 *
	 * Note that many of these cases need not be explicitly tested, as
	 * they simply degrade to "all different" cases (eg, 11):
	 *
	 * 4: ancest:(empty)^, head:head, remote:remote = result:no merge
	 * 7: ancest:ancest+, head:(empty), remote:remote = result:no merge
	 * 9: ancest:ancest+, head:head, remote:(empty) = result:no merge
	 * 11: ancest:ancest+, head:head, remote:remote = result:no merge
	 */

	/* 5ALT: ancest:*, head:head, remote:head = result:head */
	if (ours_changed && !ours_empty && !ours_theirs_differ)
		result = &conflict->our_entry;
	/* 6: ancest:ancest+, head:(empty), remote:(empty) = result:no merge */
	else if (ours_changed && ours_empty && theirs_empty)
		*resolved = 0;
	/* 8: ancest:ancest^, head:(empty), remote:ancest = result:no merge */
	else if (ours_empty && !theirs_changed)
		*resolved = 0;
	/* 10: ancest:ancest^, head:ancest, remote:(empty) = result:no merge */
	else if (!ours_changed && theirs_empty)
		*resolved = 0;
	/* 13: ancest:ancest+, head:head, remote:ancest = result:head */
	else if (ours_changed && !theirs_changed)
		result = &conflict->our_entry;
	/* 14: ancest:ancest+, head:ancest, remote:remote = result:remote */
	else if (!ours_changed && theirs_changed)
		result = &conflict->their_entry;
	else
		*resolved = 0;

	if (result != NULL &&
		GIT_MERGE_INDEX_ENTRY_EXISTS(*result) &&
		(error = git_vector_insert(&diff_list->staged, (void *)result)) >= 0)
		*resolved = 1;

	/* Note: trivial resolution does not update the REUC. */
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	return error;
}

static int merge_conflict_resolve_one_removed(
	int *resolved,
	git_merge_diff_list *diff_list,
	const git_merge_diff *conflict)
{
	int ours_empty, theirs_empty;
	int ours_changed, theirs_changed;
	int error = 0;

	assert(resolved && diff_list && conflict);

	*resolved = 0;

	if (conflict->type == GIT_MERGE_DIFF_DIRECTORY_FILE ||
		conflict->type == GIT_MERGE_DIFF_RENAMED_ADDED)
		return 0;

	ours_empty = !GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry);
	theirs_empty = !GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry);

	ours_changed = (conflict->our_status != GIT_DELTA_UNMODIFIED);
	theirs_changed = (conflict->their_status != GIT_DELTA_UNMODIFIED);

	/* Removed in both */
	if (ours_changed && ours_empty && theirs_empty)
		*resolved = 1;
	/* Removed in ours */
	else if (ours_empty && !theirs_changed)
		*resolved = 1;
	/* Removed in theirs */
	else if (!ours_changed && theirs_empty)
		*resolved = 1;

	if (*resolved)
		git_vector_insert(&diff_list->resolved, (git_merge_diff *)conflict);

	return error;
}

static int merge_conflict_resolve_one_renamed(
	int *resolved,
	git_merge_diff_list *diff_list,
	const git_merge_diff *conflict)
{
	int ours_renamed, theirs_renamed;
	int ours_changed, theirs_changed;
	git_index_entry *merged;
	int error = 0;
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	assert(resolved && diff_list && conflict);
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	*resolved = 0;

	if (!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry) ||
		!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry))
		return 0;

	ours_renamed = (conflict->our_status == GIT_DELTA_RENAMED);
	theirs_renamed = (conflict->their_status == GIT_DELTA_RENAMED);
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	if (!ours_renamed && !theirs_renamed)
		return 0;

	/* Reject one file in a 2->1 conflict */
	if (conflict->type == GIT_MERGE_DIFF_BOTH_RENAMED_2_TO_1 ||
		conflict->type == GIT_MERGE_DIFF_BOTH_RENAMED_1_TO_2 ||
		conflict->type == GIT_MERGE_DIFF_RENAMED_ADDED)
		return 0;

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	ours_changed = (git_oid__cmp(&conflict->ancestor_entry.id, &conflict->our_entry.id) != 0);
	theirs_changed = (git_oid__cmp(&conflict->ancestor_entry.id, &conflict->their_entry.id) != 0);
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	/* if both are modified (and not to a common target) require a merge */
	if (ours_changed && theirs_changed &&
782
		git_oid__cmp(&conflict->our_entry.id, &conflict->their_entry.id) != 0)
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		return 0;

785
	if ((merged = git_pool_malloc(&diff_list->pool, sizeof(git_index_entry))) == NULL)
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		return -1;
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	if (ours_changed)
		memcpy(merged, &conflict->our_entry, sizeof(git_index_entry));
	else
		memcpy(merged, &conflict->their_entry, sizeof(git_index_entry));

	if (ours_renamed)
		merged->path = conflict->our_entry.path;
	else
		merged->path = conflict->their_entry.path;
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	*resolved = 1;
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	git_vector_insert(&diff_list->staged, merged);
	git_vector_insert(&diff_list->resolved, (git_merge_diff *)conflict);
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	return error;
}

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static bool merge_conflict_can_resolve_contents(
	const git_merge_diff *conflict)
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{
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	if (!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry) ||
		!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry))
811
		return false;
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	/* Reject D/F conflicts */
	if (conflict->type == GIT_MERGE_DIFF_DIRECTORY_FILE)
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		return false;
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	/* Reject submodules. */
	if (S_ISGITLINK(conflict->ancestor_entry.mode) ||
		S_ISGITLINK(conflict->our_entry.mode) ||
		S_ISGITLINK(conflict->their_entry.mode))
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		return false;
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	/* Reject link/file conflicts. */
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	if ((S_ISLNK(conflict->ancestor_entry.mode) ^
			S_ISLNK(conflict->our_entry.mode)) ||
		(S_ISLNK(conflict->ancestor_entry.mode) ^
			S_ISLNK(conflict->their_entry.mode)))
		return false;
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	/* Reject name conflicts */
	if (conflict->type == GIT_MERGE_DIFF_BOTH_RENAMED_2_TO_1 ||
		conflict->type == GIT_MERGE_DIFF_RENAMED_ADDED)
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		return false;
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	if ((conflict->our_status & GIT_DELTA_RENAMED) == GIT_DELTA_RENAMED &&
		(conflict->their_status & GIT_DELTA_RENAMED) == GIT_DELTA_RENAMED &&
		strcmp(conflict->ancestor_entry.path, conflict->their_entry.path) != 0)
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		return false;

	return true;
}

static int merge_conflict_invoke_driver(
	git_index_entry **out,
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	const char *name,
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	git_merge_driver *driver,
	git_merge_diff_list *diff_list,
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	git_merge_driver_source *src)
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{
	git_index_entry *result;
	git_buf buf = GIT_BUF_INIT;
	const char *path;
	uint32_t mode;
	git_odb *odb = NULL;
	git_oid oid;
	int error;

	*out = NULL;

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	if ((error = driver->apply(driver, &path, &mode, &buf, name, src)) < 0 ||
		(error = git_repository_odb(&odb, src->repo)) < 0 ||
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		(error = git_odb_write(&oid, odb, buf.ptr, buf.size, GIT_OBJ_BLOB)) < 0)
		goto done;

	result = git_pool_mallocz(&diff_list->pool, sizeof(git_index_entry));
	GITERR_CHECK_ALLOC(result);

	git_oid_cpy(&result->id, &oid);
	result->mode = mode;
	result->file_size = buf.size;

	result->path = git_pool_strdup(&diff_list->pool, path);
	GITERR_CHECK_ALLOC(result->path);

	*out = result;

done:
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	git_buf_dispose(&buf);
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	git_odb_free(odb);

	return error;
}

static int merge_conflict_resolve_contents(
	int *resolved,
	git_merge_diff_list *diff_list,
	const git_merge_diff *conflict,
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	const git_merge_options *merge_opts,
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	const git_merge_file_options *file_opts)
{
	git_merge_driver_source source = {0};
	git_merge_file_result result = {0};
	git_merge_driver *driver;
894
	git_merge_driver__builtin builtin = {{0}};
895 896
	git_index_entry *merge_result;
	git_odb *odb = NULL;
897
	const char *name;
898 899
	bool fallback = false;
	int error;
900 901 902 903 904 905

	assert(resolved && diff_list && conflict);

	*resolved = 0;

	if (!merge_conflict_can_resolve_contents(conflict))
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		return 0;

908
	source.repo = diff_list->repo;
909
	source.default_driver = merge_opts->default_driver;
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	source.file_opts = file_opts;
	source.ancestor = GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->ancestor_entry) ?
912
		&conflict->ancestor_entry : NULL;
913
	source.ours = GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry) ?
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		&conflict->our_entry : NULL;
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	source.theirs = GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry) ?
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		&conflict->their_entry : NULL;

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	if (file_opts->favor != GIT_MERGE_FILE_FAVOR_NORMAL) {
		/* if the user requested a particular type of resolution (via the
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		 * favor flag) then let that override the gitattributes and use
		 * the builtin driver.
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		 */
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		name = "text";
		builtin.base.apply = git_merge_driver__builtin_apply;
		builtin.favor = file_opts->favor;

		driver = &builtin.base;
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	} else {
		/* find the merge driver for this file */
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		if ((error = git_merge_driver_for_source(&name, &driver, &source)) < 0)
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			goto done;
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		if (driver == NULL)
			fallback = true;
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	}

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	if (driver) {
		error = merge_conflict_invoke_driver(&merge_result, name, driver,
			diff_list, &source);

		if (error == GIT_PASSTHROUGH)
			fallback = true;
	}
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945
	if (fallback) {
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		error = merge_conflict_invoke_driver(&merge_result, "text",
			&git_merge_driver__text.base, diff_list, &source);
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	}
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	if (error < 0) {
		if (error == GIT_EMERGECONFLICT)
			error = 0;
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		goto done;
	}
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	git_vector_insert(&diff_list->staged, merge_result);
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	git_vector_insert(&diff_list->resolved, (git_merge_diff *)conflict);

	*resolved = 1;

done:
	git_merge_file_result_free(&result);
	git_odb_free(odb);
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	return error;
}

static int merge_conflict_resolve(
	int *out,
	git_merge_diff_list *diff_list,
	const git_merge_diff *conflict,
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	const git_merge_options *merge_opts,
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	const git_merge_file_options *file_opts)
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{
	int resolved = 0;
	int error = 0;
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	*out = 0;
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	if ((error = merge_conflict_resolve_trivial(
			&resolved, diff_list, conflict)) < 0)
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		goto done;

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	if (!resolved && (error = merge_conflict_resolve_one_removed(
			&resolved, diff_list, conflict)) < 0)
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		goto done;
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	if (!resolved && (error = merge_conflict_resolve_one_renamed(
			&resolved, diff_list, conflict)) < 0)
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		goto done;
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	if (!resolved && (error = merge_conflict_resolve_contents(
			&resolved, diff_list, conflict, merge_opts, file_opts)) < 0)
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		goto done;
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	*out = resolved;
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done:
	return error;
}

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/* Rename detection and coalescing */

struct merge_diff_similarity {
	unsigned char similarity;
	size_t other_idx;
};

static int index_entry_similarity_calc(
	void **out,
	git_repository *repo,
	git_index_entry *entry,
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	const git_merge_options *opts)
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{
	git_blob *blob;
	git_diff_file diff_file = {{{0}}};
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	git_off_t blobsize;
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	int error;
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	*out = NULL;

1023
	if ((error = git_blob_lookup(&blob, repo, &entry->id)) < 0)
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		return error;
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1026
	git_oid_cpy(&diff_file.id, &entry->id);
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	diff_file.path = entry->path;
	diff_file.size = entry->file_size;
	diff_file.mode = entry->mode;
	diff_file.flags = 0;
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1032 1033 1034 1035 1036
	blobsize = git_blob_rawsize(blob);

	/* file too big for rename processing */
	if (!git__is_sizet(blobsize))
		return 0;
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	error = opts->metric->buffer_signature(out, &diff_file,
1039
		git_blob_rawcontent(blob), (size_t)blobsize,
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		opts->metric->payload);
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	git_blob_free(blob);

	return error;
}

static int index_entry_similarity_inexact(
	git_repository *repo,
	git_index_entry *a,
	size_t a_idx,
	git_index_entry *b,
	size_t b_idx,
	void **cache,
1054
	const git_merge_options *opts)
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{
	int score = 0;
	int error = 0;
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1059
	if (!GIT_MODE_ISBLOB(a->mode) || !GIT_MODE_ISBLOB(b->mode))
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		return 0;
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	/* update signature cache if needed */
	if (!cache[a_idx] && (error = index_entry_similarity_calc(&cache[a_idx], repo, a, opts)) < 0)
		return error;
	if (!cache[b_idx] && (error = index_entry_similarity_calc(&cache[b_idx], repo, b, opts)) < 0)
		return error;
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	/* some metrics may not wish to process this file (too big / too small) */
	if (!cache[a_idx] || !cache[b_idx])
		return 0;

	/* compare signatures */
	if (opts->metric->similarity(
		&score, cache[a_idx], cache[b_idx], opts->metric->payload) < 0)
		return -1;
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	/* clip score */
	if (score < 0)
		score = 0;
	else if (score > 100)
		score = 100;
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	return score;
}

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/* Tracks deletes by oid for merge_diff_mark_similarity_exact().  This is a
* non-shrinking queue where next_pos is the next position to dequeue. 
*/
typedef struct {
	git_array_t(size_t) arr;
	size_t next_pos;
	size_t first_entry;
} deletes_by_oid_queue;

static void deletes_by_oid_free(git_oidmap *map) {
	deletes_by_oid_queue *queue;

	if (!map)
		return;

	git_oidmap_foreach_value(map, queue, {
		git_array_clear(queue->arr);
	});
	git_oidmap_free(map);
}

static int deletes_by_oid_enqueue(git_oidmap *map, git_pool* pool, const git_oid *id, size_t idx) {
	khint_t pos;
	deletes_by_oid_queue *queue;
	size_t *array_entry;
	int error;

	pos = git_oidmap_lookup_index(map, id);
	if (!git_oidmap_valid_index(map, pos)) {
		queue = git_pool_malloc(pool, sizeof(deletes_by_oid_queue));
		GITERR_CHECK_ALLOC(queue);

		git_array_init(queue->arr);
		queue->next_pos = 0;
		queue->first_entry = idx;

		git_oidmap_insert(map, id, queue, &error);
		if (error < 0)
			return -1;
	} else {
		queue = git_oidmap_value_at(map, pos);
		array_entry = git_array_alloc(queue->arr);
		GITERR_CHECK_ALLOC(array_entry);
		*array_entry = idx;
	}

	return 0;
}

static int deletes_by_oid_dequeue(size_t *idx, git_oidmap *map, const git_oid *id) {
	khint_t pos;
	deletes_by_oid_queue *queue;
	size_t *array_entry;

	pos = git_oidmap_lookup_index(map, id);

	if (!git_oidmap_valid_index(map, pos))
		return GIT_ENOTFOUND;

	queue = git_oidmap_value_at(map, pos);
	
	if (queue->next_pos == 0) {
		*idx = queue->first_entry;
	} else {
		array_entry = git_array_get(queue->arr, queue->next_pos - 1);
		if (array_entry == NULL)
			return GIT_ENOTFOUND;

		*idx = *array_entry;
	}

	queue->next_pos++;
	return 0;
}

static int merge_diff_mark_similarity_exact(
	git_merge_diff_list *diff_list,
	struct merge_diff_similarity *similarity_ours,
	struct merge_diff_similarity *similarity_theirs)
{
	size_t i, j;
	git_merge_diff *conflict_src, *conflict_tgt;
1168
	git_oidmap *ours_deletes_by_oid = NULL, *theirs_deletes_by_oid = NULL;
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	int error = 0;

	if (!(ours_deletes_by_oid = git_oidmap_alloc()) ||
		!(theirs_deletes_by_oid = git_oidmap_alloc())) {
		error = -1;
		goto done;
	}

	/* Build a map of object ids to conflicts */
	git_vector_foreach(&diff_list->conflicts, i, conflict_src) {
		/* Items can be the source of a rename iff they have an item in the
		* ancestor slot and lack an item in the ours or theirs slot. */
		if (!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_src->ancestor_entry))
			continue;

		if (!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_src->our_entry)) {
			error = deletes_by_oid_enqueue(ours_deletes_by_oid, &diff_list->pool, &conflict_src->ancestor_entry.id, i);
			if (error < 0)
				goto done;
		}

		if (!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_src->their_entry)) {
			error = deletes_by_oid_enqueue(theirs_deletes_by_oid, &diff_list->pool, &conflict_src->ancestor_entry.id, i);
			if (error < 0)
				goto done;
		}
	}

	git_vector_foreach(&diff_list->conflicts, j, conflict_tgt) {
		if (GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_tgt->ancestor_entry))
			continue;

		if (GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_tgt->our_entry)) {
			if (deletes_by_oid_dequeue(&i, ours_deletes_by_oid, &conflict_tgt->our_entry.id) == 0) {
				similarity_ours[i].similarity = 100;
				similarity_ours[i].other_idx = j;

				similarity_ours[j].similarity = 100;
				similarity_ours[j].other_idx = i;
			}
		}

		if (GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_tgt->their_entry)) {
			if (deletes_by_oid_dequeue(&i, theirs_deletes_by_oid, &conflict_tgt->their_entry.id) == 0) {
				similarity_theirs[i].similarity = 100;
				similarity_theirs[i].other_idx = j;

				similarity_theirs[j].similarity = 100;
				similarity_theirs[j].other_idx = i;
			}
		}
	}

done:
	deletes_by_oid_free(ours_deletes_by_oid);
	deletes_by_oid_free(theirs_deletes_by_oid);

	return error;
}

static int merge_diff_mark_similarity_inexact(
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	git_repository *repo,
	git_merge_diff_list *diff_list,
	struct merge_diff_similarity *similarity_ours,
	struct merge_diff_similarity *similarity_theirs,
	void **cache,
1235
	const git_merge_options *opts)
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{
	size_t i, j;
	git_merge_diff *conflict_src, *conflict_tgt;
	int similarity;
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	git_vector_foreach(&diff_list->conflicts, i, conflict_src) {
		/* Items can be the source of a rename iff they have an item in the
		 * ancestor slot and lack an item in the ours or theirs slot. */
		if (!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_src->ancestor_entry) ||
			(GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_src->our_entry) &&
			 GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_src->their_entry)))
			continue;
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		git_vector_foreach(&diff_list->conflicts, j, conflict_tgt) {
			size_t our_idx = diff_list->conflicts.length + j;
			size_t their_idx = (diff_list->conflicts.length * 2) + j;
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			if (GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_tgt->ancestor_entry))
				continue;
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			if (GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_tgt->our_entry) &&
				!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_src->our_entry)) {
1258
				similarity = index_entry_similarity_inexact(repo, &conflict_src->ancestor_entry, i, &conflict_tgt->our_entry, our_idx, cache, opts);
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				if (similarity == GIT_EBUFS)
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					continue;
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				else if (similarity < 0)
					return similarity;
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				if (similarity > similarity_ours[i].similarity &&
					similarity > similarity_ours[j].similarity) {
					/* Clear previous best similarity */
					if (similarity_ours[i].similarity > 0)
						similarity_ours[similarity_ours[i].other_idx].similarity = 0;
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					if (similarity_ours[j].similarity > 0)
						similarity_ours[similarity_ours[j].other_idx].similarity = 0;
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					similarity_ours[i].similarity = similarity;
					similarity_ours[i].other_idx = j;
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					similarity_ours[j].similarity = similarity;
					similarity_ours[j].other_idx = i;
				}
			}
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			if (GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_tgt->their_entry) &&
				!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict_src->their_entry)) {
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				similarity = index_entry_similarity_inexact(repo, &conflict_src->ancestor_entry, i, &conflict_tgt->their_entry, their_idx, cache, opts);
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				if (similarity > similarity_theirs[i].similarity &&
					similarity > similarity_theirs[j].similarity) {
					/* Clear previous best similarity */
					if (similarity_theirs[i].similarity > 0)
						similarity_theirs[similarity_theirs[i].other_idx].similarity = 0;
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					if (similarity_theirs[j].similarity > 0)
						similarity_theirs[similarity_theirs[j].other_idx].similarity = 0;
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					similarity_theirs[i].similarity = similarity;
					similarity_theirs[i].other_idx = j;
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					similarity_theirs[j].similarity = similarity;
					similarity_theirs[j].other_idx = i;
				}
			}
		}
	}
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	return 0;
}

/*
 * Rename conflicts:
 *
 *      Ancestor   Ours   Theirs
 *
 * 0a   A          A      A        No rename
 *  b   A          A*     A        No rename (ours was rewritten)
 *  c   A          A      A*       No rename (theirs rewritten)
 * 1a   A          A      B[A]     Rename or rename/edit
 *  b   A          B[A]   A        (automergeable)
 * 2    A          B[A]   B[A]     Both renamed (automergeable)
 * 3a   A          B[A]            Rename/delete
 *  b   A                 B[A]      (same)
 * 4a   A          B[A]   B        Rename/add [B~ours B~theirs]
 *  b   A          B      B[A]      (same)
 * 5    A          B[A]   C[A]     Both renamed ("1 -> 2")
 * 6    A          C[A]            Both renamed ("2 -> 1")
 *      B                 C[B]     [C~ours C~theirs]    (automergeable)
 */
static void merge_diff_mark_rename_conflict(
	git_merge_diff_list *diff_list,
	struct merge_diff_similarity *similarity_ours,
	bool ours_renamed,
	size_t ours_source_idx,
	struct merge_diff_similarity *similarity_theirs,
	bool theirs_renamed,
	size_t theirs_source_idx,
	git_merge_diff *target,
1336
	const git_merge_options *opts)
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{
	git_merge_diff *ours_source = NULL, *theirs_source = NULL;
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	if (ours_renamed)
		ours_source = diff_list->conflicts.contents[ours_source_idx];
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	if (theirs_renamed)
		theirs_source = diff_list->conflicts.contents[theirs_source_idx];
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	/* Detect 2->1 conflicts */
	if (ours_renamed && theirs_renamed) {
		/* Both renamed to the same target name. */
		if (ours_source_idx == theirs_source_idx)
			ours_source->type = GIT_MERGE_DIFF_BOTH_RENAMED;
		else {
			ours_source->type = GIT_MERGE_DIFF_BOTH_RENAMED_2_TO_1;
			theirs_source->type = GIT_MERGE_DIFF_BOTH_RENAMED_2_TO_1;
		}
	} else if (ours_renamed) {
		/* If our source was also renamed in theirs, this is a 1->2 */
		if (similarity_theirs[ours_source_idx].similarity >= opts->rename_threshold)
			ours_source->type = GIT_MERGE_DIFF_BOTH_RENAMED_1_TO_2;
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		else if (GIT_MERGE_INDEX_ENTRY_EXISTS(target->their_entry)) {
			ours_source->type = GIT_MERGE_DIFF_RENAMED_ADDED;
			target->type = GIT_MERGE_DIFF_RENAMED_ADDED;
		}
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		else if (!GIT_MERGE_INDEX_ENTRY_EXISTS(ours_source->their_entry))
			ours_source->type = GIT_MERGE_DIFF_RENAMED_DELETED;
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		else if (ours_source->type == GIT_MERGE_DIFF_MODIFIED_DELETED)
			ours_source->type = GIT_MERGE_DIFF_RENAMED_MODIFIED;
	} else if (theirs_renamed) {
		/* If their source was also renamed in ours, this is a 1->2 */
		if (similarity_ours[theirs_source_idx].similarity >= opts->rename_threshold)
			theirs_source->type = GIT_MERGE_DIFF_BOTH_RENAMED_1_TO_2;
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		else if (GIT_MERGE_INDEX_ENTRY_EXISTS(target->our_entry)) {
			theirs_source->type = GIT_MERGE_DIFF_RENAMED_ADDED;
			target->type = GIT_MERGE_DIFF_RENAMED_ADDED;
		}
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		else if (!GIT_MERGE_INDEX_ENTRY_EXISTS(theirs_source->our_entry))
			theirs_source->type = GIT_MERGE_DIFF_RENAMED_DELETED;
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		else if (theirs_source->type == GIT_MERGE_DIFF_MODIFIED_DELETED)
			theirs_source->type = GIT_MERGE_DIFF_RENAMED_MODIFIED;
	}
}

GIT_INLINE(void) merge_diff_coalesce_rename(
	git_index_entry *source_entry,
	git_delta_t *source_status,
	git_index_entry *target_entry,
	git_delta_t *target_status)
{
	/* Coalesce the rename target into the rename source. */
	memcpy(source_entry, target_entry, sizeof(git_index_entry));
	*source_status = GIT_DELTA_RENAMED;
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	memset(target_entry, 0x0, sizeof(git_index_entry));
	*target_status = GIT_DELTA_UNMODIFIED;
}

static void merge_diff_list_coalesce_renames(
	git_merge_diff_list *diff_list,
	struct merge_diff_similarity *similarity_ours,
	struct merge_diff_similarity *similarity_theirs,
1406
	const git_merge_options *opts)
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{
	size_t i;
	bool ours_renamed = 0, theirs_renamed = 0;
	size_t ours_source_idx = 0, theirs_source_idx = 0;
	git_merge_diff *ours_source, *theirs_source, *target;
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	for (i = 0; i < diff_list->conflicts.length; i++) {
		target = diff_list->conflicts.contents[i];
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		ours_renamed = 0;
		theirs_renamed = 0;
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		if (GIT_MERGE_INDEX_ENTRY_EXISTS(target->our_entry) &&
			similarity_ours[i].similarity >= opts->rename_threshold) {
			ours_source_idx = similarity_ours[i].other_idx;
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			ours_source = diff_list->conflicts.contents[ours_source_idx];
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			merge_diff_coalesce_rename(
				&ours_source->our_entry,
				&ours_source->our_status,
				&target->our_entry,
				&target->our_status);
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			similarity_ours[ours_source_idx].similarity = 0;
			similarity_ours[i].similarity = 0;
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			ours_renamed = 1;
		}
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		/* insufficient to determine direction */
		if (GIT_MERGE_INDEX_ENTRY_EXISTS(target->their_entry) &&
			similarity_theirs[i].similarity >= opts->rename_threshold) {
			theirs_source_idx = similarity_theirs[i].other_idx;
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			theirs_source = diff_list->conflicts.contents[theirs_source_idx];
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			merge_diff_coalesce_rename(
				&theirs_source->their_entry,
				&theirs_source->their_status,
				&target->their_entry,
				&target->their_status);
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			similarity_theirs[theirs_source_idx].similarity = 0;
			similarity_theirs[i].similarity = 0;
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			theirs_renamed = 1;
		}
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		merge_diff_mark_rename_conflict(diff_list,
			similarity_ours, ours_renamed, ours_source_idx,
			similarity_theirs, theirs_renamed, theirs_source_idx,
			target, opts);
	}
}

1463
static int merge_diff_empty(const git_vector *conflicts, size_t idx, void *p)
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{
	git_merge_diff *conflict = conflicts->contents[idx];
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	GIT_UNUSED(p);

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	return (!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->ancestor_entry) &&
		!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry) &&
		!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry));
}

static void merge_diff_list_count_candidates(
	git_merge_diff_list *diff_list,
	size_t *src_count,
	size_t *tgt_count)
{
	git_merge_diff *entry;
	size_t i;

	*src_count = 0;
	*tgt_count = 0;
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	git_vector_foreach(&diff_list->conflicts, i, entry) {
		if (GIT_MERGE_INDEX_ENTRY_EXISTS(entry->ancestor_entry) &&
			(!GIT_MERGE_INDEX_ENTRY_EXISTS(entry->our_entry) ||
			!GIT_MERGE_INDEX_ENTRY_EXISTS(entry->their_entry)))
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			(*src_count)++;
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		else if (!GIT_MERGE_INDEX_ENTRY_EXISTS(entry->ancestor_entry))
1491
			(*tgt_count)++;
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	}
}

int git_merge_diff_list__find_renames(
	git_repository *repo,
	git_merge_diff_list *diff_list,
1498
	const git_merge_options *opts)
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{
	struct merge_diff_similarity *similarity_ours, *similarity_theirs;
	void **cache = NULL;
	size_t cache_size = 0;
	size_t src_count, tgt_count, i;
	int error = 0;
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	assert(diff_list && opts);
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1508
	if ((opts->flags & GIT_MERGE_FIND_RENAMES) == 0)
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		return 0;
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	similarity_ours = git__calloc(diff_list->conflicts.length,
		sizeof(struct merge_diff_similarity));
	GITERR_CHECK_ALLOC(similarity_ours);
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	similarity_theirs = git__calloc(diff_list->conflicts.length,
		sizeof(struct merge_diff_similarity));
	GITERR_CHECK_ALLOC(similarity_theirs);
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	/* Calculate similarity between items that were deleted from the ancestor
	 * and added in the other branch.
	 */
1522
	if ((error = merge_diff_mark_similarity_exact(diff_list, similarity_ours, similarity_theirs)) < 0)
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		goto done;

1525
	if (opts->rename_threshold < 100 && diff_list->conflicts.length <= opts->target_limit) {
1526
		GITERR_CHECK_ALLOC_MULTIPLY(&cache_size, diff_list->conflicts.length, 3);
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		cache = git__calloc(cache_size, sizeof(void *));
		GITERR_CHECK_ALLOC(cache);

		merge_diff_list_count_candidates(diff_list, &src_count, &tgt_count);
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		if (src_count > opts->target_limit || tgt_count > opts->target_limit) {
			/* TODO: report! */
		} else {
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			if ((error = merge_diff_mark_similarity_inexact(
				repo, diff_list, similarity_ours, similarity_theirs, cache, opts)) < 0)
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				goto done;
		}
	}

	/* For entries that are appropriately similar, merge the new name's entry
	 * into the old name.
	 */
	merge_diff_list_coalesce_renames(diff_list, similarity_ours, similarity_theirs, opts);
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	/* And remove any entries that were merged and are now empty. */
1547
	git_vector_remove_matching(&diff_list->conflicts, merge_diff_empty, NULL);
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done:
	if (cache != NULL) {
		for (i = 0; i < cache_size; ++i) {
			if (cache[i] != NULL)
				opts->metric->free_signature(cache[i], opts->metric->payload);
		}

		git__free(cache);
	}

	git__free(similarity_ours);
	git__free(similarity_theirs);

	return error;
}

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/* Directory/file conflict handling */

GIT_INLINE(const char *) merge_diff_path(
	const git_merge_diff *conflict)
{
	if (GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->ancestor_entry))
		return conflict->ancestor_entry.path;
	else if (GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry))
		return conflict->our_entry.path;
	else if (GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry))
		return conflict->their_entry.path;
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	return NULL;
}

GIT_INLINE(bool) merge_diff_any_side_added_or_modified(
	const git_merge_diff *conflict)
{
	if (conflict->our_status == GIT_DELTA_ADDED ||
		conflict->our_status == GIT_DELTA_MODIFIED ||
		conflict->their_status == GIT_DELTA_ADDED ||
		conflict->their_status == GIT_DELTA_MODIFIED)
		return true;
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	return false;
}

GIT_INLINE(bool) path_is_prefixed(const char *parent, const char *child)
{
	size_t child_len = strlen(child);
	size_t parent_len = strlen(parent);
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	if (child_len < parent_len ||
		strncmp(parent, child, parent_len) != 0)
		return 0;
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	return (child[parent_len] == '/');
}

GIT_INLINE(int) merge_diff_detect_df_conflict(
	struct merge_diff_df_data *df_data,
	git_merge_diff *conflict)
{
	const char *cur_path = merge_diff_path(conflict);
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	/* Determine if this is a D/F conflict or the child of one */
	if (df_data->df_path &&
		path_is_prefixed(df_data->df_path, cur_path))
		conflict->type = GIT_MERGE_DIFF_DF_CHILD;
	else if(df_data->df_path)
		df_data->df_path = NULL;
	else if (df_data->prev_path &&
		merge_diff_any_side_added_or_modified(df_data->prev_conflict) &&
		merge_diff_any_side_added_or_modified(conflict) &&
		path_is_prefixed(df_data->prev_path, cur_path)) {
		conflict->type = GIT_MERGE_DIFF_DF_CHILD;
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		df_data->prev_conflict->type = GIT_MERGE_DIFF_DIRECTORY_FILE;
		df_data->df_path = df_data->prev_path;
	}
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	df_data->prev_path = cur_path;
	df_data->prev_conflict = conflict;
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	return 0;
}

/* Conflict handling */

GIT_INLINE(int) merge_diff_detect_type(
	git_merge_diff *conflict)
{
	if (conflict->our_status == GIT_DELTA_ADDED &&
		conflict->their_status == GIT_DELTA_ADDED)
		conflict->type = GIT_MERGE_DIFF_BOTH_ADDED;
	else if (conflict->our_status == GIT_DELTA_MODIFIED &&
			 conflict->their_status == GIT_DELTA_MODIFIED)
		conflict->type = GIT_MERGE_DIFF_BOTH_MODIFIED;
	else if (conflict->our_status == GIT_DELTA_DELETED &&
			 conflict->their_status == GIT_DELTA_DELETED)
		conflict->type = GIT_MERGE_DIFF_BOTH_DELETED;
	else if (conflict->our_status == GIT_DELTA_MODIFIED &&
			 conflict->their_status == GIT_DELTA_DELETED)
		conflict->type = GIT_MERGE_DIFF_MODIFIED_DELETED;
	else if (conflict->our_status == GIT_DELTA_DELETED &&
			 conflict->their_status == GIT_DELTA_MODIFIED)
		conflict->type = GIT_MERGE_DIFF_MODIFIED_DELETED;
	else
		conflict->type = GIT_MERGE_DIFF_NONE;
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	return 0;
}

1658
GIT_INLINE(int) index_entry_dup_pool(
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	git_index_entry *out,
	git_pool *pool,
	const git_index_entry *src)
{
	if (src != NULL) {
		memcpy(out, src, sizeof(git_index_entry));
		if ((out->path = git_pool_strdup(pool, src->path)) == NULL)
			return -1;
	}
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	return 0;
}

GIT_INLINE(int) merge_delta_type_from_index_entries(
	const git_index_entry *ancestor,
	const git_index_entry *other)
{
	if (ancestor == NULL && other == NULL)
		return GIT_DELTA_UNMODIFIED;
	else if (ancestor == NULL && other != NULL)
		return GIT_DELTA_ADDED;
	else if (ancestor != NULL && other == NULL)
		return GIT_DELTA_DELETED;
	else if (S_ISDIR(ancestor->mode) ^ S_ISDIR(other->mode))
		return GIT_DELTA_TYPECHANGE;
	else if(S_ISLNK(ancestor->mode) ^ S_ISLNK(other->mode))
		return GIT_DELTA_TYPECHANGE;
1686
	else if (git_oid__cmp(&ancestor->id, &other->id) ||
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			 ancestor->mode != other->mode)
		return GIT_DELTA_MODIFIED;
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	return GIT_DELTA_UNMODIFIED;
}

static git_merge_diff *merge_diff_from_index_entries(
	git_merge_diff_list *diff_list,
	const git_index_entry **entries)
{
	git_merge_diff *conflict;
	git_pool *pool = &diff_list->pool;
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1700
	if ((conflict = git_pool_mallocz(pool, sizeof(git_merge_diff))) == NULL)
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		return NULL;
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	if (index_entry_dup_pool(&conflict->ancestor_entry, pool, entries[TREE_IDX_ANCESTOR]) < 0 ||
		index_entry_dup_pool(&conflict->our_entry, pool, entries[TREE_IDX_OURS]) < 0 ||
		index_entry_dup_pool(&conflict->their_entry, pool, entries[TREE_IDX_THEIRS]) < 0)
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		return NULL;
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	conflict->our_status = merge_delta_type_from_index_entries(
		entries[TREE_IDX_ANCESTOR], entries[TREE_IDX_OURS]);
	conflict->their_status = merge_delta_type_from_index_entries(
		entries[TREE_IDX_ANCESTOR], entries[TREE_IDX_THEIRS]);
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	return conflict;
}

/* Merge trees */

1718
static int merge_diff_list_insert_conflict(
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	git_merge_diff_list *diff_list,
	struct merge_diff_df_data *merge_df_data,
	const git_index_entry *tree_items[3])
{
	git_merge_diff *conflict;
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	if ((conflict = merge_diff_from_index_entries(diff_list, tree_items)) == NULL ||
		merge_diff_detect_type(conflict) < 0 ||
		merge_diff_detect_df_conflict(merge_df_data, conflict) < 0 ||
		git_vector_insert(&diff_list->conflicts, conflict) < 0)
		return -1;
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	return 0;
}

1734
static int merge_diff_list_insert_unmodified(
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	git_merge_diff_list *diff_list,
	const git_index_entry *tree_items[3])
{
	int error = 0;
	git_index_entry *entry;
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1741
	entry = git_pool_malloc(&diff_list->pool, sizeof(git_index_entry));
Edward Thomson committed
1742
	GITERR_CHECK_ALLOC(entry);
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1743

1744
	if ((error = index_entry_dup_pool(entry, &diff_list->pool, tree_items[0])) >= 0)
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1745
		error = git_vector_insert(&diff_list->staged, entry);
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1747 1748 1749
	return error;
}

1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777
struct merge_diff_find_data {
	git_merge_diff_list *diff_list;
	struct merge_diff_df_data df_data;
};

static int queue_difference(const git_index_entry **entries, void *data)
{
	struct merge_diff_find_data *find_data = data;
	bool item_modified = false;
	size_t i;

	if (!entries[0] || !entries[1] || !entries[2]) {
		item_modified = true;
	} else {
		for (i = 1; i < 3; i++) {
			if (index_entry_cmp(entries[0], entries[i]) != 0) {
				item_modified = true;
				break;
			}
		}
	}

	return item_modified ?
		merge_diff_list_insert_conflict(
			find_data->diff_list, &find_data->df_data, entries) :
		merge_diff_list_insert_unmodified(find_data->diff_list, entries);
}

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1778 1779
int git_merge_diff_list__find_differences(
	git_merge_diff_list *diff_list,
1780 1781 1782
	git_iterator *ancestor_iter,
	git_iterator *our_iter,
	git_iterator *their_iter)
Edward Thomson committed
1783
{
1784
	git_iterator *iterators[3] = { ancestor_iter, our_iter, their_iter };
1785
	struct merge_diff_find_data find_data = { diff_list };
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1786

1787
	return git_iterator_walk(iterators, 3, queue_difference, &find_data);
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}

git_merge_diff_list *git_merge_diff_list__alloc(git_repository *repo)
{
	git_merge_diff_list *diff_list = git__calloc(1, sizeof(git_merge_diff_list));
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1794 1795
	if (diff_list == NULL)
		return NULL;
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1796

Edward Thomson committed
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	diff_list->repo = repo;
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1799 1800
	git_pool_init(&diff_list->pool, 1);

Edward Thomson committed
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	if (git_vector_init(&diff_list->staged, 0, NULL) < 0 ||
		git_vector_init(&diff_list->conflicts, 0, NULL) < 0 ||
1803
		git_vector_init(&diff_list->resolved, 0, NULL) < 0) {
Jacques Germishuys committed
1804
		git_merge_diff_list__free(diff_list);
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1805
		return NULL;
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1806
	}
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	return diff_list;
}

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void git_merge_diff_list__free(git_merge_diff_list *diff_list)
{
	if (!diff_list)
		return;

	git_vector_free(&diff_list->staged);
	git_vector_free(&diff_list->conflicts);
	git_vector_free(&diff_list->resolved);
	git_pool_clear(&diff_list->pool);
	git__free(diff_list);
}

1823
static int merge_normalize_opts(
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1824
	git_repository *repo,
1825 1826
	git_merge_options *opts,
	const git_merge_options *given)
Edward Thomson committed
1827 1828
{
	git_config *cfg = NULL;
1829
	git_config_entry *entry = NULL;
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1830
	int error = 0;
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1831

Edward Thomson committed
1832
	assert(repo && opts);
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1833

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1834 1835
	if ((error = git_repository_config__weakptr(&cfg, repo)) < 0)
		return error;
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1836

1837
	if (given != NULL) {
1838
		memcpy(opts, given, sizeof(git_merge_options));
1839
	} else {
1840
		git_merge_options init = GIT_MERGE_OPTIONS_INIT;
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1841
		memcpy(opts, &init, sizeof(init));
1842
	}
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1843

1844
	if ((opts->flags & GIT_MERGE_FIND_RENAMES) && !opts->rename_threshold)
1845
		opts->rename_threshold = GIT_MERGE_DEFAULT_RENAME_THRESHOLD;
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1846

1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862
	if (given && given->default_driver) {
		opts->default_driver = git__strdup(given->default_driver);
		GITERR_CHECK_ALLOC(opts->default_driver);
	} else {
		error = git_config_get_entry(&entry, cfg, "merge.default");

		if (error == 0) {
			opts->default_driver = git__strdup(entry->value);
			GITERR_CHECK_ALLOC(opts->default_driver);
		} else if (error == GIT_ENOTFOUND) {
			error = 0;
		} else {
			goto done;
		}
	}

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1863
	if (!opts->target_limit) {
1864
		int limit = git_config__get_int_force(cfg, "merge.renamelimit", 0);
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1866 1867
		if (!limit)
			limit = git_config__get_int_force(cfg, "diff.renamelimit", 0);
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1869
		opts->target_limit = (limit <= 0) ?
1870
			GIT_MERGE_DEFAULT_TARGET_LIMIT : (unsigned int)limit;
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1871
	}
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	/* assign the internal metric with whitespace flag as payload */
	if (!opts->metric) {
		opts->metric = git__malloc(sizeof(git_diff_similarity_metric));
		GITERR_CHECK_ALLOC(opts->metric);
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1878 1879 1880 1881
		opts->metric->file_signature = git_diff_find_similar__hashsig_for_file;
		opts->metric->buffer_signature = git_diff_find_similar__hashsig_for_buf;
		opts->metric->free_signature = git_diff_find_similar__hashsig_free;
		opts->metric->similarity = git_diff_find_similar__calc_similarity;
1882
		opts->metric->payload = (void *)GIT_HASHSIG_SMART_WHITESPACE;
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1883
	}
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1885 1886 1887
done:
	git_config_entry_free(entry);
	return error;
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1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899
}


static int merge_index_insert_reuc(
	git_index *index,
	size_t idx,
	const git_index_entry *entry)
{
	const git_index_reuc_entry *reuc;
	int mode[3] = { 0, 0, 0 };
	git_oid const *oid[3] = { NULL, NULL, NULL };
	size_t i;
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Edward Thomson committed
1901 1902
	if (!GIT_MERGE_INDEX_ENTRY_EXISTS(*entry))
		return 0;
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1903

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1904 1905 1906 1907 1908 1909
	if ((reuc = git_index_reuc_get_bypath(index, entry->path)) != NULL) {
		for (i = 0; i < 3; i++) {
			mode[i] = reuc->mode[i];
			oid[i] = &reuc->oid[i];
		}
	}
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1910

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1911
	mode[idx] = entry->mode;
1912
	oid[idx] = &entry->id;
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Edward Thomson committed
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	return git_index_reuc_add(index, entry->path,
		mode[0], oid[0], mode[1], oid[1], mode[2], oid[2]);
}

1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956
static int index_update_reuc(git_index *index, git_merge_diff_list *diff_list)
{
	int error;
	size_t i;
	git_merge_diff *conflict;

	/* Add each entry in the resolved conflict to the REUC independently, since
	 * the paths may differ due to renames. */
	git_vector_foreach(&diff_list->resolved, i, conflict) {
		const git_index_entry *ancestor =
			GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->ancestor_entry) ?
			&conflict->ancestor_entry : NULL;

		const git_index_entry *ours =
			GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry) ?
			&conflict->our_entry : NULL;

		const git_index_entry *theirs =
			GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry) ?
			&conflict->their_entry : NULL;

		if (ancestor != NULL &&
			(error = merge_index_insert_reuc(index, TREE_IDX_ANCESTOR, ancestor)) < 0)
			return error;

		if (ours != NULL &&
			(error = merge_index_insert_reuc(index, TREE_IDX_OURS, ours)) < 0)
			return error;

		if (theirs != NULL &&
			(error = merge_index_insert_reuc(index, TREE_IDX_THEIRS, theirs)) < 0)
			return error;
	}

	return 0;
}

static int index_from_diff_list(git_index **out,
	git_merge_diff_list *diff_list, bool skip_reuc)
Edward Thomson committed
1957 1958 1959 1960 1961
{
	git_index *index;
	size_t i;
	git_merge_diff *conflict;
	int error = 0;
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1962

Edward Thomson committed
1963
	*out = NULL;
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1964

Edward Thomson committed
1965 1966
	if ((error = git_index_new(&index)) < 0)
		return error;
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1968 1969
	if ((error = git_index__fill(index, &diff_list->staged)) < 0)
		goto on_error;
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1970

Edward Thomson committed
1971 1972 1973 1974
	git_vector_foreach(&diff_list->conflicts, i, conflict) {
		const git_index_entry *ancestor =
			GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->ancestor_entry) ?
			&conflict->ancestor_entry : NULL;
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		const git_index_entry *ours =
			GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry) ?
			&conflict->our_entry : NULL;
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1980 1981 1982
		const git_index_entry *theirs =
			GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry) ?
			&conflict->their_entry : NULL;
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		if ((error = git_index_conflict_add(index, ancestor, ours, theirs)) < 0)
			goto on_error;
	}
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1987

Edward Thomson committed
1988 1989 1990
	/* Add each rename entry to the rename portion of the index. */
	git_vector_foreach(&diff_list->conflicts, i, conflict) {
		const char *ancestor_path, *our_path, *their_path;
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1992 1993
		if (!GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->ancestor_entry))
			continue;
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1995
		ancestor_path = conflict->ancestor_entry.path;
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1996

Edward Thomson committed
1997 1998 1999
		our_path =
			GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->our_entry) ?
			conflict->our_entry.path : NULL;
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2000

Edward Thomson committed
2001 2002 2003
		their_path =
			GIT_MERGE_INDEX_ENTRY_EXISTS(conflict->their_entry) ?
			conflict->their_entry.path : NULL;
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2004

Edward Thomson committed
2005 2006 2007 2008 2009
		if ((our_path && strcmp(ancestor_path, our_path) != 0) ||
			(their_path && strcmp(ancestor_path, their_path) != 0)) {
			if ((error = git_index_name_add(index, ancestor_path, our_path, their_path)) < 0)
				goto on_error;
		}
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2010
	}
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2011

2012 2013
	if (!skip_reuc) {
		if ((error = index_update_reuc(index, diff_list)) < 0)
Edward Thomson committed
2014 2015
			goto on_error;
	}
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2016

Edward Thomson committed
2017 2018
	*out = index;
	return 0;
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2019

Edward Thomson committed
2020 2021 2022 2023 2024
on_error:
	git_index_free(index);
	return error;
}

2025 2026
static git_iterator *iterator_given_or_empty(git_iterator **empty, git_iterator *given)
{
2027 2028
	git_iterator_options opts = GIT_ITERATOR_OPTIONS_INIT;

2029 2030 2031
	if (given)
		return given;

2032 2033 2034
	opts.flags = GIT_ITERATOR_DONT_IGNORE_CASE;

	if (git_iterator_for_nothing(empty, &opts) < 0)
2035 2036 2037 2038 2039 2040
		return NULL;

	return *empty;
}

int git_merge__iterators(
Edward Thomson committed
2041 2042
	git_index **out,
	git_repository *repo,
2043 2044 2045
	git_iterator *ancestor_iter,
	git_iterator *our_iter,
	git_iterator *theirs_iter,
2046
	const git_merge_options *given_opts)
Edward Thomson committed
2047
{
2048 2049 2050
	git_iterator *empty_ancestor = NULL,
		*empty_ours = NULL,
		*empty_theirs = NULL;
Edward Thomson committed
2051
	git_merge_diff_list *diff_list;
2052
	git_merge_options opts;
2053
	git_merge_file_options file_opts = GIT_MERGE_FILE_OPTIONS_INIT;
Edward Thomson committed
2054 2055 2056 2057 2058
	git_merge_diff *conflict;
	git_vector changes;
	size_t i;
	int error = 0;

2059
	assert(out && repo);
Edward Thomson committed
2060 2061

	*out = NULL;
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2062

2063 2064
	GITERR_CHECK_VERSION(
		given_opts, GIT_MERGE_OPTIONS_VERSION, "git_merge_options");
2065

2066
	if ((error = merge_normalize_opts(repo, &opts, given_opts)) < 0)
Edward Thomson committed
2067 2068
		return error;

2069 2070 2071 2072 2073 2074 2075 2076 2077
	file_opts.favor = opts.file_favor;
	file_opts.flags = opts.file_flags;

	/* use the git-inspired labels when virtual base building */
	if (opts.flags & GIT_MERGE__VIRTUAL_BASE) {
		file_opts.ancestor_label = "merged common ancestors";
		file_opts.our_label = "Temporary merge branch 1";
		file_opts.their_label = "Temporary merge branch 2";
		file_opts.flags |= GIT_MERGE_FILE_FAVOR__CONFLICTED;
2078
		file_opts.marker_size = GIT_MERGE_CONFLICT_MARKER_SIZE + 2;
2079 2080
	}

Edward Thomson committed
2081 2082
	diff_list = git_merge_diff_list__alloc(repo);
	GITERR_CHECK_ALLOC(diff_list);
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2083

2084 2085 2086 2087 2088 2089
	ancestor_iter = iterator_given_or_empty(&empty_ancestor, ancestor_iter);
	our_iter = iterator_given_or_empty(&empty_ours, our_iter);
	theirs_iter = iterator_given_or_empty(&empty_theirs, theirs_iter);

	if ((error = git_merge_diff_list__find_differences(
			diff_list, ancestor_iter, our_iter, theirs_iter)) < 0 ||
Edward Thomson committed
2090
		(error = git_merge_diff_list__find_renames(repo, diff_list, &opts)) < 0)
Edward Thomson committed
2091
		goto done;
nulltoken committed
2092

Edward Thomson committed
2093 2094
	memcpy(&changes, &diff_list->conflicts, sizeof(git_vector));
	git_vector_clear(&diff_list->conflicts);
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2095

Edward Thomson committed
2096 2097
	git_vector_foreach(&changes, i, conflict) {
		int resolved = 0;
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2098

2099
		if ((error = merge_conflict_resolve(
2100
			&resolved, diff_list, conflict, &opts, &file_opts)) < 0)
Edward Thomson committed
2101
			goto done;
nulltoken committed
2102

2103
		if (!resolved) {
2104
			if ((opts.flags & GIT_MERGE_FAIL_ON_CONFLICT)) {
2105 2106 2107 2108 2109
				giterr_set(GITERR_MERGE, "merge conflicts exist");
				error = GIT_EMERGECONFLICT;
				goto done;
			}

Edward Thomson committed
2110
			git_vector_insert(&diff_list->conflicts, conflict);
2111
		}
Edward Thomson committed
2112
	}
nulltoken committed
2113

2114
	error = index_from_diff_list(out, diff_list,
2115
		(opts.flags & GIT_MERGE_SKIP_REUC));
Edward Thomson committed
2116 2117

done:
Vicent Marti committed
2118 2119 2120
	if (!given_opts || !given_opts->metric)
		git__free(opts.metric);

2121 2122
	git__free((char *)opts.default_driver);

Edward Thomson committed
2123
	git_merge_diff_list__free(diff_list);
2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139
	git_iterator_free(empty_ancestor);
	git_iterator_free(empty_ours);
	git_iterator_free(empty_theirs);

	return error;
}

int git_merge_trees(
	git_index **out,
	git_repository *repo,
	const git_tree *ancestor_tree,
	const git_tree *our_tree,
	const git_tree *their_tree,
	const git_merge_options *merge_opts)
{
	git_iterator *ancestor_iter = NULL, *our_iter = NULL, *their_iter = NULL;
2140
	git_iterator_options iter_opts = GIT_ITERATOR_OPTIONS_INIT;
2141 2142
	int error;

2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156
	assert(out && repo);

	/* if one side is treesame to the ancestor, take the other side */
	if (ancestor_tree && merge_opts && (merge_opts->flags & GIT_MERGE_SKIP_REUC)) {
		const git_tree *result = NULL;
		const git_oid *ancestor_tree_id = git_tree_id(ancestor_tree);

		if (our_tree && !git_oid_cmp(ancestor_tree_id, git_tree_id(our_tree)))
			result = their_tree;
		else if (their_tree && !git_oid_cmp(ancestor_tree_id, git_tree_id(their_tree)))
			result = our_tree;

		if (result) {
			if ((error = git_index_new(out)) == 0)
2157
    			error = git_index_read_tree(*out, result);
2158 2159 2160 2161 2162

			return error;
		}
	}

2163 2164 2165 2166 2167 2168 2169 2170
	iter_opts.flags = GIT_ITERATOR_DONT_IGNORE_CASE;

	if ((error = git_iterator_for_tree(
			&ancestor_iter, (git_tree *)ancestor_tree, &iter_opts)) < 0 ||
		(error = git_iterator_for_tree(
			&our_iter, (git_tree *)our_tree, &iter_opts)) < 0 ||
		(error = git_iterator_for_tree(
			&their_iter, (git_tree *)their_tree, &iter_opts)) < 0)
2171 2172 2173 2174 2175 2176 2177 2178 2179
		goto done;

	error = git_merge__iterators(
		out, repo, ancestor_iter, our_iter, their_iter, merge_opts);

done:
	git_iterator_free(ancestor_iter);
	git_iterator_free(our_iter);
	git_iterator_free(their_iter);
Edward Thomson committed
2180 2181 2182 2183

	return error;
}

2184 2185 2186
static int merge_annotated_commits(
	git_index **index_out,
	git_annotated_commit **base_out,
2187
	git_repository *repo,
2188 2189
	git_annotated_commit *our_commit,
	git_annotated_commit *their_commit,
2190
	size_t recursion_level,
2191 2192
	const git_merge_options *opts);

2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216
GIT_INLINE(int) insert_head_ids(
	git_array_oid_t *ids,
	const git_annotated_commit *annotated_commit)
{
	git_oid *id;
	size_t i;

	if (annotated_commit->type == GIT_ANNOTATED_COMMIT_REAL) {
		id = git_array_alloc(*ids);
		GITERR_CHECK_ALLOC(id);

		git_oid_cpy(id, git_commit_id(annotated_commit->commit));
	} else {
		for (i = 0; i < annotated_commit->parents.size; i++) {
			id = git_array_alloc(*ids);
			GITERR_CHECK_ALLOC(id);

			git_oid_cpy(id, &annotated_commit->parents.ptr[i]);
		}
	}

	return 0;
}

2217
static int create_virtual_base(
2218
	git_annotated_commit **out,
2219
	git_repository *repo,
2220 2221
	git_annotated_commit *one,
	git_annotated_commit *two,
2222
	const git_merge_options *opts,
2223
	size_t recursion_level)
2224
{
2225
	git_annotated_commit *result = NULL;
2226
	git_index *index = NULL;
2227
	git_merge_options virtual_opts = GIT_MERGE_OPTIONS_INIT;
2228

2229 2230 2231 2232 2233 2234 2235 2236 2237
	/* Conflicts in the merge base creation do not propagate to conflicts
	 * in the result; the conflicted base will act as the common ancestor.
	 */
	if (opts)
		memcpy(&virtual_opts, opts, sizeof(git_merge_options));

	virtual_opts.flags &= ~GIT_MERGE_FAIL_ON_CONFLICT;
	virtual_opts.flags |= GIT_MERGE__VIRTUAL_BASE;

2238
	if ((merge_annotated_commits(&index, NULL, repo, one, two,
2239
			recursion_level + 1, &virtual_opts)) < 0)
2240
		return -1;
2241

2242 2243
	result = git__calloc(1, sizeof(git_annotated_commit));
	GITERR_CHECK_ALLOC(result);
2244 2245
	result->type = GIT_ANNOTATED_COMMIT_VIRTUAL;
	result->index = index;
2246

2247 2248
	insert_head_ids(&result->parents, one);
	insert_head_ids(&result->parents, two);
2249

2250
	*out = result;
2251 2252
	return 0;
}
2253

2254 2255 2256 2257 2258
static int compute_base(
	git_annotated_commit **out,
	git_repository *repo,
	const git_annotated_commit *one,
	const git_annotated_commit *two,
2259
	const git_merge_options *given_opts,
2260 2261 2262 2263 2264
	size_t recursion_level)
{
	git_array_oid_t head_ids = GIT_ARRAY_INIT;
	git_oidarray bases = {0};
	git_annotated_commit *base = NULL, *other = NULL, *new_base = NULL;
2265
	git_merge_options opts = GIT_MERGE_OPTIONS_INIT;
2266
	size_t i, base_count;
2267
	int error;
2268

2269
	*out = NULL;
2270

2271 2272 2273
	if (given_opts)
		memcpy(&opts, given_opts, sizeof(git_merge_options));

2274 2275 2276 2277 2278 2279 2280 2281
	/* With more than two commits, merge_bases_many finds the base of
	 * the first commit and a hypothetical merge of the others. Since
	 * "one" may itself be a virtual commit, which insert_head_ids
	 * substitutes multiple ancestors for, it needs to be added
	 * after "two" which is always a single real commit.
	 */
	if ((error = insert_head_ids(&head_ids, two)) < 0 ||
		(error = insert_head_ids(&head_ids, one)) < 0 ||
2282 2283
		(error = git_merge_bases_many(&bases, repo,
			head_ids.size, head_ids.ptr)) < 0)
2284 2285
		goto done;

2286 2287 2288 2289 2290 2291
	base_count = (opts.flags & GIT_MERGE_NO_RECURSIVE) ? 0 : bases.count;

	if (base_count)
		git_oidarray__reverse(&bases);

	if ((error = git_annotated_commit_lookup(&base, repo, &bases.ids[0])) < 0)
2292
		goto done;
2293

2294
	for (i = 1; i < base_count; i++) {
2295
		recursion_level++;
2296

2297 2298 2299
		if (opts.recursion_limit && recursion_level > opts.recursion_limit)
			break;

2300 2301
		if ((error = git_annotated_commit_lookup(&other, repo,
				&bases.ids[i])) < 0 ||
2302
			(error = create_virtual_base(&new_base, repo, base, other, &opts,
2303
				recursion_level)) < 0)
2304 2305
			goto done;

2306 2307
		git_annotated_commit_free(base);
		git_annotated_commit_free(other);
2308

2309 2310 2311
		base = new_base;
		new_base = NULL;
		other = NULL;
2312 2313 2314
	}

done:
2315 2316 2317 2318
	if (error == 0)
		*out = base;
	else
		git_annotated_commit_free(base);
2319

2320 2321 2322 2323
	git_annotated_commit_free(other);
	git_annotated_commit_free(new_base);
	git_oidarray_free(&bases);
	git_array_clear(head_ids);
2324 2325
	return error;
}
2326

2327 2328 2329 2330 2331 2332 2333 2334 2335 2336
static int iterator_for_annotated_commit(
	git_iterator **out,
	git_annotated_commit *commit)
{
	git_iterator_options opts = GIT_ITERATOR_OPTIONS_INIT;
	int error;

	opts.flags = GIT_ITERATOR_DONT_IGNORE_CASE;

	if (commit == NULL) {
2337
		error = git_iterator_for_nothing(out, &opts);
2338
	} else if (commit->type == GIT_ANNOTATED_COMMIT_VIRTUAL) {
2339
		error = git_iterator_for_index(out, git_index_owner(commit->index), commit->index, &opts);
2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351
	} else {
		if (!commit->tree &&
			(error = git_commit_tree(&commit->tree, commit->commit)) < 0)
			goto done;

		error = git_iterator_for_tree(out, commit->tree, &opts);
	}

done:
	return error;
}

2352 2353 2354
static int merge_annotated_commits(
	git_index **index_out,
	git_annotated_commit **base_out,
2355
	git_repository *repo,
2356 2357
	git_annotated_commit *ours,
	git_annotated_commit *theirs,
2358
	size_t recursion_level,
2359
	const git_merge_options *opts)
2360
{
2361
	git_annotated_commit *base = NULL;
2362
	git_iterator *base_iter = NULL, *our_iter = NULL, *their_iter = NULL;
2363
	int error;
2364

2365
	if ((error = compute_base(&base, repo, ours, theirs, opts,
2366
		recursion_level)) < 0) {
2367

2368 2369
		if (error != GIT_ENOTFOUND)
			goto done;
2370

2371 2372
		giterr_clear();
	}
2373

2374 2375 2376 2377 2378
	if ((error = iterator_for_annotated_commit(&base_iter, base)) < 0 ||
		(error = iterator_for_annotated_commit(&our_iter, ours)) < 0 ||
		(error = iterator_for_annotated_commit(&their_iter, theirs)) < 0 ||
		(error = git_merge__iterators(index_out, repo, base_iter, our_iter,
			their_iter, opts)) < 0)
2379 2380
		goto done;

2381 2382 2383 2384
	if (base_out) {
		*base_out = base;
		base = NULL;
	}
2385 2386

done:
2387
	git_annotated_commit_free(base);
2388 2389 2390
	git_iterator_free(base_iter);
	git_iterator_free(our_iter);
	git_iterator_free(their_iter);
2391 2392 2393
	return error;
}

2394

2395 2396 2397 2398 2399 2400 2401
int git_merge_commits(
	git_index **out,
	git_repository *repo,
	const git_commit *our_commit,
	const git_commit *their_commit,
	const git_merge_options *opts)
{
2402 2403 2404 2405 2406 2407
	git_annotated_commit *ours = NULL, *theirs = NULL, *base = NULL;
	int error = 0;

	if ((error = git_annotated_commit_from_commit(&ours, (git_commit *)our_commit)) < 0 ||
		(error = git_annotated_commit_from_commit(&theirs, (git_commit *)their_commit)) < 0)
		goto done;
2408

2409
	error = merge_annotated_commits(out, &base, repo, ours, theirs, 0, opts);
2410

2411 2412 2413 2414
done:
	git_annotated_commit_free(ours);
	git_annotated_commit_free(theirs);
	git_annotated_commit_free(base);
2415 2416 2417
	return error;
}

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/* Merge setup / cleanup */

static int write_merge_head(
	git_repository *repo,
2422
	const git_annotated_commit *heads[],
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	size_t heads_len)
{
	git_filebuf file = GIT_FILEBUF_INIT;
	git_buf file_path = GIT_BUF_INIT;
	size_t i;
	int error = 0;

	assert(repo && heads);

2432
	if ((error = git_buf_joinpath(&file_path, repo->gitdir, GIT_MERGE_HEAD_FILE)) < 0 ||
2433
		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_FORCE, GIT_MERGE_FILE_MODE)) < 0)
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		goto cleanup;

	for (i = 0; i < heads_len; i++) {
2437
		if ((error = git_filebuf_printf(&file, "%s\n", heads[i]->id_str)) < 0)
Edward Thomson committed
2438 2439 2440
			goto cleanup;
	}

2441
	error = git_filebuf_commit(&file);
Edward Thomson committed
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cleanup:
	if (error < 0)
		git_filebuf_cleanup(&file);

2447
	git_buf_dispose(&file_path);
Edward Thomson committed
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	return error;
}

2452
static int write_merge_mode(git_repository *repo)
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{
	git_filebuf file = GIT_FILEBUF_INIT;
	git_buf file_path = GIT_BUF_INIT;
	int error = 0;

	assert(repo);

2460
	if ((error = git_buf_joinpath(&file_path, repo->gitdir, GIT_MERGE_MODE_FILE)) < 0 ||
2461
		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_FORCE, GIT_MERGE_FILE_MODE)) < 0)
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		goto cleanup;

2464 2465
	if ((error = git_filebuf_write(&file, "no-ff", 5)) < 0)
		goto cleanup;
2466

2467
	error = git_filebuf_commit(&file);
Edward Thomson committed
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cleanup:
	if (error < 0)
		git_filebuf_cleanup(&file);

2473
	git_buf_dispose(&file_path);
Edward Thomson committed
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	return error;
}

struct merge_msg_entry {
2479
	const git_annotated_commit *merge_head;
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	bool written;
};

static int msg_entry_is_branch(
	const struct merge_msg_entry *entry,
	git_vector *entries)
{
	GIT_UNUSED(entries);

	return (entry->written == 0 &&
		entry->merge_head->remote_url == NULL &&
		entry->merge_head->ref_name != NULL &&
		git__strncmp(GIT_REFS_HEADS_DIR, entry->merge_head->ref_name, strlen(GIT_REFS_HEADS_DIR)) == 0);
}

static int msg_entry_is_tracking(
	const struct merge_msg_entry *entry,
	git_vector *entries)
{
	GIT_UNUSED(entries);

	return (entry->written == 0 &&
		entry->merge_head->remote_url == NULL &&
		entry->merge_head->ref_name != NULL &&
		git__strncmp(GIT_REFS_REMOTES_DIR, entry->merge_head->ref_name, strlen(GIT_REFS_REMOTES_DIR)) == 0);
}

static int msg_entry_is_tag(
	const struct merge_msg_entry *entry,
	git_vector *entries)
{
	GIT_UNUSED(entries);

	return (entry->written == 0 &&
		entry->merge_head->remote_url == NULL &&
		entry->merge_head->ref_name != NULL &&
		git__strncmp(GIT_REFS_TAGS_DIR, entry->merge_head->ref_name, strlen(GIT_REFS_TAGS_DIR)) == 0);
}

static int msg_entry_is_remote(
	const struct merge_msg_entry *entry,
	git_vector *entries)
{
	if (entry->written == 0 &&
		entry->merge_head->remote_url != NULL &&
		entry->merge_head->ref_name != NULL &&
		git__strncmp(GIT_REFS_HEADS_DIR, entry->merge_head->ref_name, strlen(GIT_REFS_HEADS_DIR)) == 0)
	{
		struct merge_msg_entry *existing;

		/* Match only branches from the same remote */
		if (entries->length == 0)
			return 1;

		existing = git_vector_get(entries, 0);

		return (git__strcmp(existing->merge_head->remote_url,
			entry->merge_head->remote_url) == 0);
	}

	return 0;
}

static int msg_entry_is_oid(
	const struct merge_msg_entry *merge_msg_entry)
{
	return (merge_msg_entry->written == 0 &&
		merge_msg_entry->merge_head->ref_name == NULL &&
		merge_msg_entry->merge_head->remote_url == NULL);
}

static int merge_msg_entry_written(
	const struct merge_msg_entry *merge_msg_entry)
{
	return (merge_msg_entry->written == 1);
}

static int merge_msg_entries(
	git_vector *v,
	const struct merge_msg_entry *entries,
	size_t len,
	int (*match)(const struct merge_msg_entry *entry, git_vector *entries))
{
	size_t i;
	int matches, total = 0;

	git_vector_clear(v);

	for (i = 0; i < len; i++) {
		if ((matches = match(&entries[i], v)) < 0)
			return matches;
		else if (!matches)
			continue;

		git_vector_insert(v, (struct merge_msg_entry *)&entries[i]);
		total++;
	}

	return total;
}

static int merge_msg_write_entries(
	git_filebuf *file,
	git_vector *entries,
	const char *item_name,
	const char *item_plural_name,
	size_t ref_name_skip,
	const char *source,
	char sep)
{
	struct merge_msg_entry *entry;
	size_t i;
	int error = 0;

	if (entries->length == 0)
		return 0;

	if (sep && (error = git_filebuf_printf(file, "%c ", sep)) < 0)
		goto done;

	if ((error = git_filebuf_printf(file, "%s ",
		(entries->length == 1) ? item_name : item_plural_name)) < 0)
		goto done;

	git_vector_foreach(entries, i, entry) {
		if (i > 0 &&
			(error = git_filebuf_printf(file, "%s", (i == entries->length - 1) ? " and " : ", ")) < 0)
			goto done;

		if ((error = git_filebuf_printf(file, "'%s'", entry->merge_head->ref_name + ref_name_skip)) < 0)
			goto done;

		entry->written = 1;
	}

	if (source)
		error = git_filebuf_printf(file, " of %s", source);

done:
	return error;
}

static int merge_msg_write_branches(
	git_filebuf *file,
	git_vector *entries,
	char sep)
{
	return merge_msg_write_entries(file, entries,
		"branch", "branches", strlen(GIT_REFS_HEADS_DIR), NULL, sep);
}

static int merge_msg_write_tracking(
	git_filebuf *file,
	git_vector *entries,
	char sep)
{
	return merge_msg_write_entries(file, entries,
		"remote-tracking branch", "remote-tracking branches", 0, NULL, sep);
}

static int merge_msg_write_tags(
	git_filebuf *file,
	git_vector *entries,
	char sep)
{
	return merge_msg_write_entries(file, entries,
		"tag", "tags", strlen(GIT_REFS_TAGS_DIR), NULL, sep);
}

static int merge_msg_write_remotes(
	git_filebuf *file,
	git_vector *entries,
	char sep)
{
	const char *source;

	if (entries->length == 0)
		return 0;

	source = ((struct merge_msg_entry *)entries->contents[0])->merge_head->remote_url;

	return merge_msg_write_entries(file, entries,
		"branch", "branches", strlen(GIT_REFS_HEADS_DIR), source, sep);
}

static int write_merge_msg(
	git_repository *repo,
2667
	const git_annotated_commit *heads[],
Edward Thomson committed
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	size_t heads_len)
{
	git_filebuf file = GIT_FILEBUF_INIT;
	git_buf file_path = GIT_BUF_INIT;
	struct merge_msg_entry *entries;
	git_vector matching = GIT_VECTOR_INIT;
	size_t i;
	char sep = 0;
	int error = 0;

	assert(repo && heads);

	entries = git__calloc(heads_len, sizeof(struct merge_msg_entry));
2681
	GITERR_CHECK_ALLOC(entries);
Edward Thomson committed
2682

2683 2684
	if (git_vector_init(&matching, heads_len, NULL) < 0) {
		git__free(entries);
Edward Thomson committed
2685
		return -1;
2686
	}
Edward Thomson committed
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	for (i = 0; i < heads_len; i++)
		entries[i].merge_head = heads[i];

2691
	if ((error = git_buf_joinpath(&file_path, repo->gitdir, GIT_MERGE_MSG_FILE)) < 0 ||
2692
		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_FORCE, GIT_MERGE_FILE_MODE)) < 0 ||
Edward Thomson committed
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		(error = git_filebuf_write(&file, "Merge ", 6)) < 0)
		goto cleanup;

	/*
	 * This is to emulate the format of MERGE_MSG by core git.
	 *
	 * Core git will write all the commits specified by OID, in the order
	 * provided, until the first named branch or tag is reached, at which
	 * point all branches will be written in the order provided, then all
	 * tags, then all remote tracking branches and finally all commits that
	 * were specified by OID that were not already written.
	 *
	 * Yes.  Really.
	 */
	for (i = 0; i < heads_len; i++) {
		if (!msg_entry_is_oid(&entries[i]))
			break;

2711 2712
		if ((error = git_filebuf_printf(&file,
			"%scommit '%s'", (i > 0) ? "; " : "",
2713
			entries[i].merge_head->id_str)) < 0)
Edward Thomson committed
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			goto cleanup;

		entries[i].written = 1;
	}

	if (i)
		sep = ';';

	if ((error = merge_msg_entries(&matching, entries, heads_len, msg_entry_is_branch)) < 0 ||
		(error = merge_msg_write_branches(&file, &matching, sep)) < 0)
		goto cleanup;

	if (matching.length)
		sep =',';

	if ((error = merge_msg_entries(&matching, entries, heads_len, msg_entry_is_tracking)) < 0 ||
		(error = merge_msg_write_tracking(&file, &matching, sep)) < 0)
		goto cleanup;

	if (matching.length)
		sep =',';
2735

Edward Thomson committed
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	if ((error = merge_msg_entries(&matching, entries, heads_len, msg_entry_is_tag)) < 0 ||
		(error = merge_msg_write_tags(&file, &matching, sep)) < 0)
		goto cleanup;

	if (matching.length)
		sep =',';

	/* We should never be called with multiple remote branches, but handle
	 * it in case we are... */
	while ((error = merge_msg_entries(&matching, entries, heads_len, msg_entry_is_remote)) > 0) {
		if ((error = merge_msg_write_remotes(&file, &matching, sep)) < 0)
			goto cleanup;

		if (matching.length)
			sep =',';
	}

	if (error < 0)
		goto cleanup;

	for (i = 0; i < heads_len; i++) {
		if (merge_msg_entry_written(&entries[i]))
			continue;

2760
		if ((error = git_filebuf_printf(&file, "; commit '%s'",
2761
			entries[i].merge_head->id_str)) < 0)
Edward Thomson committed
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			goto cleanup;
	}

	if ((error = git_filebuf_printf(&file, "\n")) < 0 ||
2766
		(error = git_filebuf_commit(&file)) < 0)
Edward Thomson committed
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		goto cleanup;

cleanup:
	if (error < 0)
		git_filebuf_cleanup(&file);

2773
	git_buf_dispose(&file_path);
Edward Thomson committed
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	git_vector_free(&matching);
	git__free(entries);

	return error;
}

2781 2782
int git_merge__setup(
	git_repository *repo,
2783 2784
	const git_annotated_commit *our_head,
	const git_annotated_commit *heads[],
2785 2786 2787 2788 2789 2790
	size_t heads_len)
{
	int error = 0;

	assert (repo && our_head && heads);

2791
	if ((error = git_repository__set_orig_head(repo, git_annotated_commit_id(our_head))) == 0 &&
2792 2793 2794 2795 2796 2797 2798 2799
		(error = write_merge_head(repo, heads, heads_len)) == 0 &&
		(error = write_merge_mode(repo)) == 0) {
		error = write_merge_msg(repo, heads, heads_len);
	}

	return error;
}

2800 2801 2802
/* Merge branches */

static int merge_ancestor_head(
2803
	git_annotated_commit **ancestor_head,
2804
	git_repository *repo,
2805 2806
	const git_annotated_commit *our_head,
	const git_annotated_commit **their_heads,
2807 2808 2809
	size_t their_heads_len)
{
	git_oid *oids, ancestor_oid;
2810
	size_t i, alloc_len;
2811 2812 2813 2814
	int error = 0;

	assert(repo && our_head && their_heads);

2815 2816
	GITERR_CHECK_ALLOC_ADD(&alloc_len, their_heads_len, 1);
	oids = git__calloc(alloc_len, sizeof(git_oid));
2817 2818 2819 2820 2821
	GITERR_CHECK_ALLOC(oids);

	git_oid_cpy(&oids[0], git_commit_id(our_head->commit));

	for (i = 0; i < their_heads_len; i++)
2822
		git_oid_cpy(&oids[i + 1], git_annotated_commit_id(their_heads[i]));
2823 2824 2825 2826

	if ((error = git_merge_base_many(&ancestor_oid, repo, their_heads_len + 1, oids)) < 0)
		goto on_error;

2827
	error = git_annotated_commit_lookup(ancestor_head, repo, &ancestor_oid);
2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846

on_error:
	git__free(oids);
	return error;
}

const char *merge_their_label(const char *branchname)
{
	const char *slash;

	if ((slash = strrchr(branchname, '/')) == NULL)
		return branchname;

	if (*(slash+1) == '\0')
		return "theirs";

	return slash+1;
}

2847
static int merge_normalize_checkout_opts(
2848
	git_checkout_options *out,
2849
	git_repository *repo,
2850
	const git_checkout_options *given_checkout_opts,
2851
	unsigned int checkout_strategy,
2852
	git_annotated_commit *ancestor,
2853
	const git_annotated_commit *our_head,
2854 2855
	const git_annotated_commit **their_heads,
	size_t their_heads_len)
2856
{
2857
	git_checkout_options default_checkout_opts = GIT_CHECKOUT_OPTIONS_INIT;
2858 2859 2860 2861
	int error = 0;

	GIT_UNUSED(repo);

2862
	if (given_checkout_opts != NULL)
2863 2864 2865
		memcpy(out, given_checkout_opts, sizeof(git_checkout_options));
	else
		memcpy(out, &default_checkout_opts, sizeof(git_checkout_options));
2866

2867
	out->checkout_strategy = checkout_strategy;
2868

2869
	if (!out->ancestor_label) {
2870
		if (ancestor && ancestor->type == GIT_ANNOTATED_COMMIT_REAL)
2871
			out->ancestor_label = git_commit_summary(ancestor->commit);
2872
		else if (ancestor)
2873
			out->ancestor_label = "merged common ancestors";
2874 2875
		else
			out->ancestor_label = "empty base";
2876 2877
	}

2878
	if (!out->our_label) {
2879
		if (our_head && our_head->ref_name)
2880
			out->our_label = our_head->ref_name;
2881
		else
2882
			out->our_label = "ours";
2883
	}
2884

2885
	if (!out->their_label) {
2886
		if (their_heads_len == 1 && their_heads[0]->ref_name)
2887
			out->their_label = merge_their_label(their_heads[0]->ref_name);
2888
		else if (their_heads_len == 1)
2889
			out->their_label = their_heads[0]->id_str;
2890
		else
2891
			out->their_label = "theirs";
2892 2893 2894 2895 2896 2897 2898 2899 2900 2901
	}

	return error;
}

static int merge_check_index(size_t *conflicts, git_repository *repo, git_index *index_new, git_vector *merged_paths)
{
	git_tree *head_tree = NULL;
	git_index *index_repo = NULL;
	git_iterator *iter_repo = NULL, *iter_new = NULL;
2902
	git_iterator_options iter_opts = GIT_ITERATOR_OPTIONS_INIT;
2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931
	git_diff *staged_diff_list = NULL, *index_diff_list = NULL;
	git_diff_delta *delta;
	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
	git_vector staged_paths = GIT_VECTOR_INIT;
	size_t i;
	int error = 0;

	GIT_UNUSED(merged_paths);

	*conflicts = 0;

	/* No staged changes may exist unless the change staged is identical to
	 * the result of the merge.  This allows one to apply to merge manually,
	 * then run merge.  Any other staged change would be overwritten by
	 * a reset merge.
	 */
	if ((error = git_repository_head_tree(&head_tree, repo)) < 0 ||
		(error = git_repository_index(&index_repo, repo)) < 0 ||
		(error = git_diff_tree_to_index(&staged_diff_list, repo, head_tree, index_repo, &opts)) < 0)
		goto done;

	if (staged_diff_list->deltas.length == 0)
		goto done;

	git_vector_foreach(&staged_diff_list->deltas, i, delta) {
		if ((error = git_vector_insert(&staged_paths, (char *)delta->new_file.path)) < 0)
			goto done;
	}

2932
	iter_opts.flags = GIT_ITERATOR_DONT_IGNORE_CASE;
2933 2934
	iter_opts.pathlist.strings = (char **)staged_paths.contents;
	iter_opts.pathlist.count = staged_paths.length;
2935

2936 2937
	if ((error = git_iterator_for_index(&iter_repo, repo, index_repo, &iter_opts)) < 0 ||
		(error = git_iterator_for_index(&iter_new, repo, index_new, &iter_opts)) < 0 ||
2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960
		(error = git_diff__from_iterators(&index_diff_list, repo, iter_repo, iter_new, &opts)) < 0)
		goto done;

	*conflicts = index_diff_list->deltas.length;

done:
	git_tree_free(head_tree);
	git_index_free(index_repo);
	git_iterator_free(iter_repo);
	git_iterator_free(iter_new);
	git_diff_free(staged_diff_list);
	git_diff_free(index_diff_list);
	git_vector_free(&staged_paths);

	return error;
}

static int merge_check_workdir(size_t *conflicts, git_repository *repo, git_index *index_new, git_vector *merged_paths)
{
	git_diff *wd_diff_list = NULL;
	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
	int error = 0;

Russell Belfer committed
2961 2962
	GIT_UNUSED(index_new);

2963 2964
	*conflicts = 0;

2965 2966 2967 2968 2969 2970 2971 2972 2973 2974
	/* We need to have merged at least 1 file for the possibility to exist to
	 * have conflicts with the workdir. Passing 0 as the pathspec count paramter
	 * will consider all files in the working directory, that is, we may detect
	 * a conflict if there were untracked files in the workdir prior to starting
	 * the merge. This typically happens when cherry-picking a commmit whose
	 * changes have already been applied.
	 */
	if (merged_paths->length == 0)
		return 0;

2975 2976 2977 2978 2979 2980
	opts.flags |= GIT_DIFF_INCLUDE_UNTRACKED;

	/* Workdir changes may exist iff they do not conflict with changes that
	 * will be applied by the merge (including conflicts).  Ensure that there
	 * are no changes in the workdir to these paths.
	 */
2981
	opts.flags |= GIT_DIFF_DISABLE_PATHSPEC_MATCH;
2982 2983
	opts.pathspec.count = merged_paths->length;
	opts.pathspec.strings = (char **)merged_paths->contents;
2984
	opts.ignore_submodules = GIT_SUBMODULE_IGNORE_ALL;
2985

2986
	if ((error = git_diff_index_to_workdir(&wd_diff_list, repo, NULL, &opts)) < 0)
2987 2988 2989 2990 2991 2992 2993 2994 2995 2996
		goto done;

	*conflicts = wd_diff_list->deltas.length;

done:
	git_diff_free(wd_diff_list);

	return error;
}

2997
int git_merge__check_result(git_repository *repo, git_index *index_new)
2998
{
2999 3000
	git_tree *head_tree = NULL;
	git_iterator *iter_head = NULL, *iter_new = NULL;
3001
	git_iterator_options iter_opts = GIT_ITERATOR_OPTIONS_INIT;
3002 3003 3004
	git_diff *merged_list = NULL;
	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
	git_diff_delta *delta;
3005
	git_vector paths = GIT_VECTOR_INIT;
3006
	size_t i, index_conflicts = 0, wd_conflicts = 0, conflicts;
3007 3008 3009
	const git_index_entry *e;
	int error = 0;

3010 3011
	iter_opts.flags = GIT_ITERATOR_DONT_IGNORE_CASE;

3012
	if ((error = git_repository_head_tree(&head_tree, repo)) < 0 ||
3013
		(error = git_iterator_for_tree(&iter_head, head_tree, &iter_opts)) < 0 ||
3014
		(error = git_iterator_for_index(&iter_new, repo, index_new, &iter_opts)) < 0 ||
3015
		(error = git_diff__from_iterators(&merged_list, repo, iter_head, iter_new, &opts)) < 0)
3016 3017
		goto done;

3018 3019 3020
	git_vector_foreach(&merged_list->deltas, i, delta) {
		if ((error = git_vector_insert(&paths, (char *)delta->new_file.path)) < 0)
			goto done;
3021 3022 3023 3024 3025
	}

	for (i = 0; i < git_index_entrycount(index_new); i++) {
		e = git_index_get_byindex(index_new, i);

3026
		if (git_index_entry_is_conflict(e) &&
3027 3028
			(git_vector_last(&paths) == NULL ||
			strcmp(git_vector_last(&paths), e->path) != 0)) {
3029

3030 3031 3032
			if ((error = git_vector_insert(&paths, (char *)e->path)) < 0)
				goto done;
		}
3033 3034
	}

3035 3036 3037 3038
	/* Make sure the index and workdir state do not prevent merging */
	if ((error = merge_check_index(&index_conflicts, repo, index_new, &paths)) < 0 ||
		(error = merge_check_workdir(&wd_conflicts, repo, index_new, &paths)) < 0)
		goto done;
3039

3040
	if ((conflicts = index_conflicts + wd_conflicts) > 0) {
3041
		giterr_set(GITERR_MERGE, "%" PRIuZ " uncommitted change%s would be overwritten by merge",
3042
			conflicts, (conflicts != 1) ? "s" : "");
3043
		error = GIT_ECONFLICT;
3044 3045 3046
	}

done:
3047 3048 3049 3050 3051
	git_vector_free(&paths);
	git_tree_free(head_tree);
	git_iterator_free(iter_head);
	git_iterator_free(iter_new);
	git_diff_free(merged_list);
3052 3053 3054 3055

	return error;
}

3056 3057 3058 3059 3060 3061 3062 3063 3064 3065
int git_merge__append_conflicts_to_merge_msg(
	git_repository *repo,
	git_index *index)
{
	git_filebuf file = GIT_FILEBUF_INIT;
	git_buf file_path = GIT_BUF_INIT;
	const char *last = NULL;
	size_t i;
	int error;

3066 3067 3068
	if (!git_index_has_conflicts(index))
		return 0;

3069
	if ((error = git_buf_joinpath(&file_path, repo->gitdir, GIT_MERGE_MSG_FILE)) < 0 ||
3070 3071 3072
		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_APPEND, GIT_MERGE_FILE_MODE)) < 0)
		goto cleanup;

3073
	git_filebuf_printf(&file, "\nConflicts:\n");
3074 3075 3076 3077

	for (i = 0; i < git_index_entrycount(index); i++) {
		const git_index_entry *e = git_index_get_byindex(index, i);

3078
		if (!git_index_entry_is_conflict(e))
3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092
			continue;

		if (last == NULL || strcmp(e->path, last) != 0)
			git_filebuf_printf(&file, "\t%s\n", e->path);

		last = e->path;
	}

	error = git_filebuf_commit(&file);

cleanup:
	if (error < 0)
		git_filebuf_cleanup(&file);

3093
	git_buf_dispose(&file_path);
3094 3095 3096 3097

	return error;
}

3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108
static int merge_state_cleanup(git_repository *repo)
{
	const char *state_files[] = {
		GIT_MERGE_HEAD_FILE,
		GIT_MERGE_MODE_FILE,
		GIT_MERGE_MSG_FILE,
	};

	return git_repository__cleanup_files(repo, state_files, ARRAY_SIZE(state_files));
}

3109
static int merge_heads(
3110 3111
	git_annotated_commit **ancestor_head_out,
	git_annotated_commit **our_head_out,
3112
	git_repository *repo,
3113
	git_reference *our_ref,
3114
	const git_annotated_commit **their_heads,
3115
	size_t their_heads_len)
3116
{
3117
	git_annotated_commit *ancestor_head = NULL, *our_head = NULL;
3118 3119 3120 3121 3122 3123 3124 3125
	int error = 0;

	*ancestor_head_out = NULL;
	*our_head_out = NULL;

	if ((error = git_repository__ensure_not_bare(repo, "merge")) < 0)
		goto done;

3126
	if ((error = git_annotated_commit_from_ref(&our_head, repo, our_ref)) < 0)
3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141
		goto done;

	if ((error = merge_ancestor_head(&ancestor_head, repo, our_head, their_heads, their_heads_len)) < 0) {
		if (error != GIT_ENOTFOUND)
			goto done;

		giterr_clear();
		error = 0;
	}

	*ancestor_head_out = ancestor_head;
	*our_head_out = our_head;

done:
	if (error < 0) {
3142 3143
		git_annotated_commit_free(ancestor_head);
		git_annotated_commit_free(our_head);
3144 3145 3146 3147 3148
	}

	return error;
}

3149
static int merge_preference(git_merge_preference_t *out, git_repository *repo)
3150 3151 3152 3153 3154
{
	git_config *config;
	const char *value;
	int bool_value, error = 0;

3155
	*out = GIT_MERGE_PREFERENCE_NONE;
3156

Edward Thomson committed
3157
	if ((error = git_repository_config_snapshot(&config, repo)) < 0)
3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170
		goto done;

	if ((error = git_config_get_string(&value, config, "merge.ff")) < 0) {
		if (error == GIT_ENOTFOUND) {
			giterr_clear();
			error = 0;
		}

		goto done;
	}

	if (git_config_parse_bool(&bool_value, value) == 0) {
		if (!bool_value)
3171
			*out |= GIT_MERGE_PREFERENCE_NO_FASTFORWARD;
3172 3173
	} else {
		if (strcasecmp(value, "only") == 0)
3174
			*out |= GIT_MERGE_PREFERENCE_FASTFORWARD_ONLY;
3175 3176 3177 3178 3179 3180 3181
	}

done:
	git_config_free(config);
	return error;
}

3182
int git_merge_analysis_for_ref(
3183
	git_merge_analysis_t *analysis_out,
3184
	git_merge_preference_t *preference_out,
3185
	git_repository *repo,
3186
	git_reference *our_ref,
3187
	const git_annotated_commit **their_heads,
3188 3189
	size_t their_heads_len)
{
3190
	git_annotated_commit *ancestor_head = NULL, *our_head = NULL;
3191
	int error = 0;
3192
	bool unborn;
3193

3194
	assert(analysis_out && preference_out && repo && their_heads);
3195

3196
	if (their_heads_len != 1) {
3197
		giterr_set(GITERR_MERGE, "can only merge a single branch");
3198 3199 3200 3201
		error = -1;
		goto done;
	}

3202
	*analysis_out = GIT_MERGE_ANALYSIS_NONE;
3203

3204
	if ((error = merge_preference(preference_out, repo)) < 0)
3205
		goto done;
3206

3207 3208 3209 3210
	if ((error = git_reference__is_unborn_head(&unborn, our_ref, repo)) < 0)
		goto done;

	if (unborn) {
3211
		*analysis_out |= GIT_MERGE_ANALYSIS_FASTFORWARD | GIT_MERGE_ANALYSIS_UNBORN;
3212
		error = 0;
3213
		goto done;
3214 3215
	}

3216
	if ((error = merge_heads(&ancestor_head, &our_head, repo, our_ref, their_heads, their_heads_len)) < 0)
3217
		goto done;
3218

3219
	/* We're up-to-date if we're trying to merge our own common ancestor. */
3220 3221
	if (ancestor_head && git_oid_equal(
		git_annotated_commit_id(ancestor_head), git_annotated_commit_id(their_heads[0])))
3222
		*analysis_out |= GIT_MERGE_ANALYSIS_UP_TO_DATE;
3223

3224
	/* We're fastforwardable if we're our own common ancestor. */
3225 3226
	else if (ancestor_head && git_oid_equal(
		git_annotated_commit_id(ancestor_head), git_annotated_commit_id(our_head)))
3227
		*analysis_out |= GIT_MERGE_ANALYSIS_FASTFORWARD | GIT_MERGE_ANALYSIS_NORMAL;
3228

3229 3230
	/* Otherwise, just a normal merge is possible. */
	else
3231
		*analysis_out |= GIT_MERGE_ANALYSIS_NORMAL;
3232

3233
done:
3234 3235
	git_annotated_commit_free(ancestor_head);
	git_annotated_commit_free(our_head);
3236 3237
	return error;
}
3238

3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260
int git_merge_analysis(
	git_merge_analysis_t *analysis_out,
	git_merge_preference_t *preference_out,
	git_repository *repo,
	const git_annotated_commit **their_heads,
	size_t their_heads_len)
{
	git_reference *head_ref = NULL;
	int error = 0;

	if ((error = git_reference_lookup(&head_ref, repo, GIT_HEAD_FILE)) < 0) {
		giterr_set(GITERR_MERGE, "failed to lookup HEAD reference");
		return error;
	}

	error = git_merge_analysis_for_ref(analysis_out, preference_out, repo, head_ref, their_heads, their_heads_len);

	git_reference_free(head_ref);

	return error;
}

3261 3262
int git_merge(
	git_repository *repo,
3263
	const git_annotated_commit **their_heads,
3264
	size_t their_heads_len,
3265
	const git_merge_options *merge_opts,
3266
	const git_checkout_options *given_checkout_opts)
3267 3268
{
	git_reference *our_ref = NULL;
3269
	git_checkout_options checkout_opts;
3270
	git_annotated_commit *our_head = NULL, *base = NULL;
3271
	git_index *index = NULL;
3272
	git_indexwriter indexwriter = GIT_INDEXWRITER_INIT;
3273
	unsigned int checkout_strategy;
3274
	int error = 0;
3275

3276
	assert(repo && their_heads);
3277 3278

	if (their_heads_len != 1) {
3279
		giterr_set(GITERR_MERGE, "can only merge a single branch");
3280 3281 3282
		return -1;
	}

3283 3284
	if ((error = git_repository__ensure_not_bare(repo, "merge")) < 0)
		goto done;
3285

3286 3287 3288
	checkout_strategy = given_checkout_opts ?
		given_checkout_opts->checkout_strategy :
		GIT_CHECKOUT_SAFE;
3289

3290 3291 3292
	if ((error = git_indexwriter_init_for_operation(&indexwriter, repo,
		&checkout_strategy)) < 0)
		goto done;
3293

3294 3295 3296 3297 3298
	/* Write the merge setup files to the repository. */
	if ((error = git_annotated_commit_from_head(&our_head, repo)) < 0 ||
		(error = git_merge__setup(repo, our_head, their_heads,
			their_heads_len)) < 0)
		goto done;
3299

3300
	/* TODO: octopus */
3301

3302
	if ((error = merge_annotated_commits(&index, &base, repo, our_head,
3303
			(git_annotated_commit *)their_heads[0], 0, merge_opts)) < 0 ||
3304
		(error = git_merge__check_result(repo, index)) < 0 ||
3305 3306
		(error = git_merge__append_conflicts_to_merge_msg(repo, index)) < 0)
		goto done;
3307

3308
	/* check out the merge results */
3309

3310 3311
	if ((error = merge_normalize_checkout_opts(&checkout_opts, repo,
			given_checkout_opts, checkout_strategy,
3312
			base, our_head, their_heads, their_heads_len)) < 0 ||
3313 3314 3315 3316
		(error = git_checkout_index(repo, index, &checkout_opts)) < 0)
		goto done;

	error = git_indexwriter_commit(&indexwriter);
3317 3318

done:
3319 3320
	if (error < 0)
		merge_state_cleanup(repo);
3321

3322
	git_indexwriter_cleanup(&indexwriter);
3323
	git_index_free(index);
3324
	git_annotated_commit_free(our_head);
3325
	git_annotated_commit_free(base);
3326 3327 3328 3329 3330
	git_reference_free(our_ref);

	return error;
}

3331
int git_merge_init_options(git_merge_options *opts, unsigned int version)
3332
{
3333 3334 3335
	GIT_INIT_STRUCTURE_FROM_TEMPLATE(
		opts, version, git_merge_options, GIT_MERGE_OPTIONS_INIT);
	return 0;
3336
}
3337

3338
int git_merge_file_init_input(git_merge_file_input *input, unsigned int version)
3339
{
3340 3341 3342
	GIT_INIT_STRUCTURE_FROM_TEMPLATE(
		input, version, git_merge_file_input, GIT_MERGE_FILE_INPUT_INIT);
	return 0;
3343 3344
}

3345 3346
int git_merge_file_init_options(
	git_merge_file_options *opts, unsigned int version)
3347
{
3348 3349 3350
	GIT_INIT_STRUCTURE_FROM_TEMPLATE(
		opts, version, git_merge_file_options, GIT_MERGE_FILE_OPTIONS_INIT);
	return 0;
3351
}