Merge pull request #4705 from libgit2/ethomson/apply

Patch (diff) application

include/git2.h

@@ -9,6 +9,7 @@
 #define INCLUDE_git_git_h__
 
 #include "git2/annotated_commit.h"
+#include "git2/apply.h"
 #include "git2/attr.h"
 #include "git2/blob.h"
 #include "git2/blame.h"

include/git2/apply.h

+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_git_apply_h__
+#define INCLUDE_git_apply_h__
+
+#include "common.h"
+#include "types.h"
+#include "oid.h"
+#include "diff.h"
+
+/**
+ * @file git2/apply.h
+ * @brief Git patch application routines
+ * @defgroup git_apply Git patch application routines
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * When applying a patch, callback that will be made per delta (file).
+ *
+ * When the callback:
+ * - returns < 0, the apply process will be aborted.
+ * - returns > 0, the delta will not be applied, but the apply process
+ *      continues
+ * - returns 0, the delta is applied, and the apply process continues.
+ *
+ * @param delta The delta to be applied
+ * @param payload User-specified payload
+ */
+typedef int (*git_apply_delta_cb)(
+	const git_diff_delta *delta,
+	void *payload);
+
+/**
+ * When applying a patch, callback that will be made per hunk.
+ *
+ * When the callback:
+ * - returns < 0, the apply process will be aborted.
+ * - returns > 0, the hunk will not be applied, but the apply process
+ *      continues
+ * - returns 0, the hunk is applied, and the apply process continues.
+ *
+ * @param hunk The hunk to be applied
+ * @param payload User-specified payload
+ */
+typedef int (*git_apply_hunk_cb)(
+	const git_diff_hunk *hunk,
+	void *payload);
+
+/**
+ * Apply options structure
+ *
+ * Initialize with `GIT_APPLY_OPTIONS_INIT`. Alternatively, you can
+ * use `git_apply_init_options`.
+ *
+ * @see git_apply_to_tree, git_apply
+ */
+typedef struct {
+	unsigned int version;
+
+	git_apply_delta_cb delta_cb;
+	git_apply_hunk_cb hunk_cb;
+	void *payload;
+} git_apply_options;
+
+#define GIT_APPLY_OPTIONS_VERSION 1
+#define GIT_APPLY_OPTIONS_INIT {GIT_APPLY_OPTIONS_VERSION}
+
+/**
+ * Apply a `git_diff` to a `git_tree`, and return the resulting image
+ * as an index.
+ *
+ * @param out the postimage of the application
+ * @param repo the repository to apply
+ * @param preimage the tree to apply the diff to
+ * @param diff the diff to apply
+ * @param options the options for the apply (or null for defaults)
+ */
+GIT_EXTERN(int) git_apply_to_tree(
+	git_index **out,
+	git_repository *repo,
+	git_tree *preimage,
+	git_diff *diff,
+	const git_apply_options *options);
+
+typedef enum {
+	/**
+	 * Apply the patch to the workdir, leaving the index untouched.
+	 * This is the equivalent of `git apply` with no location argument.
+	 */
+	GIT_APPLY_LOCATION_WORKDIR = 0,
+
+	/**
+	 * Apply the patch to the index, leaving the working directory
+	 * untouched.  This is the equivalent of `git apply --cached`.
+	 */
+	GIT_APPLY_LOCATION_INDEX = 1,
+
+	/**
+	 * Apply the patch to both the working directory and the index.
+	 * This is the equivalent of `git apply --index`.
+	 */
+	GIT_APPLY_LOCATION_BOTH = 2,
+} git_apply_location_t;
+
+/**
+ * Apply a `git_diff` to the given repository, making changes directly
+ * in the working directory, the index, or both.
+ *
+ * @param repo the repository to apply to
+ * @param diff the diff to apply
+ * @param location the location to apply (workdir, index or both)
+ * @param options the options for the apply (or null for defaults)
+ */
+GIT_EXTERN(int) git_apply(
+	git_repository *repo,
+	git_diff *diff,
+	git_apply_location_t location,
+	const git_apply_options *options);
+
+/** @} */
+GIT_END_DECL
+#endif

include/git2/errors.h

@@ -57,6 +57,7 @@ typedef enum {
 	GIT_RETRY           = -32,	/**< Internal only */
 	GIT_EMISMATCH       = -33,	/**< Hashsum mismatch in object */
 	GIT_EINDEXDIRTY     = -34,	/**< Unsaved changes in the index would be overwritten */
+	GIT_EAPPLYFAIL      = -35,	/**< Patch application failed */
 } git_error_code;
 
 /**

src/apply.h

@@ -10,6 +10,7 @@
 #include "common.h"
 
 #include "git2/patch.h"
+#include "git2/apply.h"
 #include "buffer.h"
 
 extern int git_apply__patch(
@@ -18,6 +19,7 @@ extern int git_apply__patch(
 	unsigned int *mode,
 	const char *source,
 	size_t source_len,
-	git_patch *patch);
+	git_patch *patch,
+	const git_apply_options *opts);
 
 #endif

src/iterator.c

@@ -1015,6 +1015,7 @@ typedef struct {
 	struct stat st;
 	size_t path_len;
 	iterator_pathlist_search_t match;
+	git_oid id;
 	char path[GIT_FLEX_ARRAY];
 } filesystem_iterator_entry;
 
@@ -1265,7 +1266,32 @@ GIT_INLINE(bool) filesystem_iterator_is_dot_git(
 	return (len == 4 || path[len - 5] == '/');
 }
 
-static filesystem_iterator_entry *filesystem_iterator_entry_init(
+static int filesystem_iterator_entry_hash(
+	filesystem_iterator *iter,
+	filesystem_iterator_entry *entry)
+{
+	git_buf fullpath = GIT_BUF_INIT;
+	int error;
+
+	if (S_ISDIR(entry->st.st_mode)) {
+		memset(&entry->id, 0, GIT_OID_RAWSZ);
+		return 0;
+	}
+
+	if (iter->base.type == GIT_ITERATOR_TYPE_WORKDIR)
+		return git_repository_hashfile(&entry->id,
+			iter->base.repo, entry->path, GIT_OBJ_BLOB, NULL);
+
+	if (!(error = git_buf_joinpath(&fullpath, iter->root, entry->path)))
+		error = git_odb_hashfile(&entry->id, fullpath.ptr, GIT_OBJ_BLOB);
+
+	git_buf_dispose(&fullpath);
+	return error;
+}
+
+static int filesystem_iterator_entry_init(
+	filesystem_iterator_entry **out,
+	filesystem_iterator *iter,
 	filesystem_iterator_frame *frame,
 	const char *path,
 	size_t path_len,
@@ -1274,15 +1300,19 @@ static filesystem_iterator_entry *filesystem_iterator_entry_init(
 {
 	filesystem_iterator_entry *entry;
 	size_t entry_size;
+	int error = 0;
+
+	*out = NULL;
 
 	/* Make sure to append two bytes, one for the path's null
 	 * termination, one for a possible trailing '/' for folders.
 	 */
-	if (GIT_ADD_SIZET_OVERFLOW(&entry_size,
-			sizeof(filesystem_iterator_entry), path_len) ||
-		GIT_ADD_SIZET_OVERFLOW(&entry_size, entry_size, 2) ||
-		(entry = git_pool_malloc(&frame->entry_pool, entry_size)) == NULL)
-		return NULL;
+	GITERR_CHECK_ALLOC_ADD(&entry_size,
+		sizeof(filesystem_iterator_entry), path_len);
+	GITERR_CHECK_ALLOC_ADD(&entry_size, entry_size, 2);
+
+	entry = git_pool_malloc(&frame->entry_pool, entry_size);
+	GITERR_CHECK_ALLOC(entry);
 
 	entry->path_len = path_len;
 	entry->match = pathlist_match;
@@ -1295,7 +1325,13 @@ static filesystem_iterator_entry *filesystem_iterator_entry_init(
 
 	entry->path[entry->path_len] = '\0';
 
-	return entry;
+	if (iter->base.flags & GIT_ITERATOR_INCLUDE_HASH)
+		error = filesystem_iterator_entry_hash(iter, entry);
+
+	if (!error)
+		*out = entry;
+
+	return error;
 }
 
 static int filesystem_iterator_frame_push(
@@ -1418,9 +1454,9 @@ static int filesystem_iterator_frame_push(
 		else if (dir_expected)
 			continue;
 
-		entry = filesystem_iterator_entry_init(new_frame,
-			path, path_len, &statbuf, pathlist_match);
-		GITERR_CHECK_ALLOC(entry);
+		if ((error = filesystem_iterator_entry_init(&entry,
+			iter, new_frame, path, path_len, &statbuf, pathlist_match)) < 0)
+			goto done;
 
 		git_vector_insert(&new_frame->entries, entry);
 	}
@@ -1460,7 +1496,7 @@ static void filesystem_iterator_set_current(
 	iter->entry.ctime.seconds = entry->st.st_ctime;
 	iter->entry.mtime.seconds = entry->st.st_mtime;
 
-#if defined(GIT_USE_NSEC)	
+#if defined(GIT_USE_NSEC)
 	iter->entry.ctime.nanoseconds = entry->st.st_ctime_nsec;
 	iter->entry.mtime.nanoseconds = entry->st.st_mtime_nsec;
 #else
@@ -1475,6 +1511,9 @@ static void filesystem_iterator_set_current(
 	iter->entry.gid = entry->st.st_gid;
 	iter->entry.file_size = entry->st.st_size;
 
+	if (iter->base.flags & GIT_ITERATOR_INCLUDE_HASH)
+		git_oid_cpy(&iter->entry.id, &entry->id);
+
 	iter->entry.path = entry->path;
 
 	iter->current_is_ignored = GIT_IGNORE_UNCHECKED;
@@ -2259,6 +2298,35 @@ void git_iterator_free(git_iterator *iter)
 	git__free(iter);
 }
 
+int git_iterator_foreach(
+	git_iterator *iterator,
+	git_iterator_foreach_cb cb,
+	void *data)
+{
+	const git_index_entry *iterator_item;
+	int error = 0;
+
+	if ((error = git_iterator_current(&iterator_item, iterator)) < 0)
+		goto done;
+
+	if ((error = cb(iterator_item, data)) != 0)
+		goto done;
+
+	while (true) {
+		if ((error = git_iterator_advance(&iterator_item, iterator)) < 0)
+			goto done;
+
+		if ((error = cb(iterator_item, data)) != 0)
+			goto done;
+	}
+
+done:
+	if (error == GIT_ITEROVER)
+		error = 0;
+
+	return error;
+}
+
 int git_iterator_walk(
 	git_iterator **iterators,
 	size_t cnt,

src/iterator.h

@@ -41,6 +41,8 @@ typedef enum {
 	GIT_ITERATOR_INCLUDE_CONFLICTS = (1u << 6),
 	/** descend into symlinked directories */
 	GIT_ITERATOR_DESCEND_SYMLINKS = (1u << 7),
+	/** hash files in workdir or filesystem iterators */
+	GIT_ITERATOR_INCLUDE_HASH = (1u << 8),
 } git_iterator_flag_t;
 
 typedef enum {
@@ -289,6 +291,19 @@ extern int git_iterator_current_workdir_path(
  */
 extern git_index *git_iterator_index(git_iterator *iter);
 
+typedef int (*git_iterator_foreach_cb)(
+	const git_index_entry *entry,
+	void *data);
+
+/**
+ * Walk the given iterator and invoke the callback for each path
+ * contained in the iterator.
+ */
+extern int git_iterator_foreach(
+	git_iterator *iterator,
+	git_iterator_foreach_cb cb,
+	void *data);
+
 typedef int (*git_iterator_walk_cb)(
 	const git_index_entry **entries,
 	void *data);

src/reader.c

+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "reader.h"
+
+#include "fileops.h"
+#include "blob.h"
+
+#include "git2/tree.h"
+#include "git2/blob.h"
+#include "git2/index.h"
+#include "git2/repository.h"
+
+/* tree reader */
+
+typedef struct {
+	git_reader reader;
+	git_tree *tree;
+} tree_reader;
+
+static int tree_reader_read(
+	git_buf *out,
+	git_oid *out_id,
+	git_filemode_t *out_filemode,
+	git_reader *_reader,
+	const char *filename)
+{
+	tree_reader *reader = (tree_reader *)_reader;
+	git_tree_entry *tree_entry = NULL;
+	git_blob *blob = NULL;
+	int error;
+
+	if ((error = git_tree_entry_bypath(&tree_entry, reader->tree, filename)) < 0 ||
+	    (error = git_blob_lookup(&blob, git_tree_owner(reader->tree), git_tree_entry_id(tree_entry))) < 0 ||
+	    (error = git_buf_set(out, git_blob_rawcontent(blob), git_blob_rawsize(blob))) < 0)
+		goto done;
+
+	if (out_id)
+		git_oid_cpy(out_id, git_tree_entry_id(tree_entry));
+
+	if (out_filemode)
+		*out_filemode = git_tree_entry_filemode(tree_entry);
+
+done:
+	git_blob_free(blob);
+	git_tree_entry_free(tree_entry);
+	return error;
+}
+
+int git_reader_for_tree(git_reader **out, git_tree *tree)
+{
+	tree_reader *reader;
+
+	assert(out && tree);
+
+	reader = git__calloc(1, sizeof(tree_reader));
+	GITERR_CHECK_ALLOC(reader);
+
+	reader->reader.read = tree_reader_read;
+	reader->tree = tree;
+
+	*out = (git_reader *)reader;
+	return 0;
+}
+
+/* workdir reader */
+
+typedef struct {
+	git_reader reader;
+	git_repository *repo;
+	git_index *index;
+} workdir_reader;
+
+static int workdir_reader_read(
+	git_buf *out,
+	git_oid *out_id,
+	git_filemode_t *out_filemode,
+	git_reader *_reader,
+	const char *filename)
+{
+	workdir_reader *reader = (workdir_reader *)_reader;
+	git_buf path = GIT_BUF_INIT;
+	struct stat st;
+	git_filemode_t filemode;
+	git_filter_list *filters = NULL;
+	const git_index_entry *idx_entry;
+	git_oid id;
+	int error;
+
+	if ((error = git_buf_joinpath(&path,
+		git_repository_workdir(reader->repo), filename)) < 0)
+		goto done;
+
+	if ((error = p_lstat(path.ptr, &st)) < 0) {
+		if (error == -1 && errno == ENOENT)
+			error = GIT_ENOTFOUND;
+
+		giterr_set(GITERR_OS, "could not stat '%s'", path.ptr);
+		goto done;
+	}
+
+	filemode = git_futils_canonical_mode(st.st_mode);
+
+	/*
+	 * Patch application - for example - uses the filtered version of
+	 * the working directory data to match git.  So we will run the
+	 * workdir -> ODB filter on the contents in this workdir reader.
+	 */
+	if ((error = git_filter_list_load(&filters, reader->repo, NULL, filename,
+		GIT_FILTER_TO_ODB, GIT_FILTER_DEFAULT)) < 0)
+		goto done;
+
+	if ((error = git_filter_list_apply_to_file(out,
+	    filters, reader->repo, path.ptr)) < 0)
+		goto done;
+
+	if (out_id || reader->index) {
+		if ((error = git_odb_hash(&id, out->ptr, out->size, GIT_OBJ_BLOB)) < 0)
+			goto done;
+	}
+
+	if (reader->index) {
+		if (!(idx_entry = git_index_get_bypath(reader->index, filename, 0)) ||
+		    filemode != idx_entry->mode ||
+		    !git_oid_equal(&id, &idx_entry->id)) {
+			error = GIT_READER_MISMATCH;
+			goto done;
+		}
+	}
+
+	if (out_id)
+		git_oid_cpy(out_id, &id);
+
+	if (out_filemode)
+		*out_filemode = filemode;
+
+done:
+	git_filter_list_free(filters);
+	git_buf_dispose(&path);
+	return error;
+}
+
+int git_reader_for_workdir(
+	git_reader **out,
+	git_repository *repo,
+	bool validate_index)
+{
+	workdir_reader *reader;
+	int error;
+
+	assert(out && repo);
+
+	reader = git__calloc(1, sizeof(workdir_reader));
+	GITERR_CHECK_ALLOC(reader);
+
+	reader->reader.read = workdir_reader_read;
+	reader->repo = repo;
+
+	if (validate_index &&
+	    (error = git_repository_index__weakptr(&reader->index, repo)) < 0) {
+		git__free(reader);
+		return error;
+	}
+
+	*out = (git_reader *)reader;
+	return 0;
+}
+
+/* index reader */
+
+typedef struct {
+	git_reader reader;
+	git_repository *repo;
+	git_index *index;
+} index_reader;
+
+static int index_reader_read(
+	git_buf *out,
+	git_oid *out_id,
+	git_filemode_t *out_filemode,
+	git_reader *_reader,
+	const char *filename)
+{
+	index_reader *reader = (index_reader *)_reader;
+	const git_index_entry *entry;
+	git_blob *blob;
+	int error;
+
+	if ((entry = git_index_get_bypath(reader->index, filename, 0)) == NULL)
+		return GIT_ENOTFOUND;
+
+	if ((error = git_blob_lookup(&blob, reader->repo, &entry->id)) < 0)
+		goto done;
+
+	if (out_id)
+		git_oid_cpy(out_id, &entry->id);
+
+	if (out_filemode)
+		*out_filemode = entry->mode;
+
+	error = git_blob__getbuf(out, blob);
+
+done:
+	git_blob_free(blob);
+	return error;
+}
+
+int git_reader_for_index(
+	git_reader **out,
+	git_repository *repo,
+	git_index *index)
+{
+	index_reader *reader;
+	int error;
+
+	assert(out && repo);
+
+	reader = git__calloc(1, sizeof(index_reader));
+	GITERR_CHECK_ALLOC(reader);
+
+	reader->reader.read = index_reader_read;
+	reader->repo = repo;
+
+	if (index) {
+		reader->index = index;
+	} else if ((error = git_repository_index__weakptr(&reader->index, repo)) < 0) {
+		git__free(reader);
+		return error;
+	}
+
+	*out = (git_reader *)reader;
+	return 0;
+}
+
+/* generic */
+
+int git_reader_read(
+	git_buf *out,
+	git_oid *out_id,
+	git_filemode_t *out_filemode,
+	git_reader *reader,
+	const char *filename)
+{
+	assert(out && reader && filename);
+
+	return reader->read(out, out_id, out_filemode, reader, filename);
+}
+
+void git_reader_free(git_reader *reader)
+{
+	if (!reader)
+		return;
+
+	git__free(reader);
+}

src/reader.h

+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_reader_h__
+#define INCLUDE_reader_h__
+
+#include "common.h"
+
+/* Returned when the workdir does not match the index */
+#define GIT_READER_MISMATCH	1
+
+typedef struct git_reader git_reader;
+
+/*
+ * The `git_reader` structure is a generic interface for reading the
+ * contents of a file by its name, and implementations are provided
+ * for reading out of a tree, the index, and the working directory.
+ *
+ * Note that the reader implementation is meant to have a short
+ * lifecycle and does not increase the refcount of the object that
+ * it's reading.  Callers should ensure that they do not use a
+ * reader after disposing the underlying object that it reads.
+ */
+struct git_reader {
+	int (*read)(git_buf *out, git_oid *out_oid, git_filemode_t *mode, git_reader *reader, const char *filename);
+};
+
+/**
+ * Create a `git_reader` that will allow random access to the given
+ * tree.  Paths requested via `git_reader_read` will be rooted at this
+ * tree, callers are not expected to recurse through tree lookups.  Thus,
+ * you can request to read `/src/foo.c` and the tree provided to this
+ * function will be searched to find another tree named `src`, which
+ * will then be opened to find `foo.c`.
+ *
+ * @param out The reader for the given tree
+ * @param tree The tree object to read
+ * @return 0 on success, or an error code < 0
+ */
+extern int git_reader_for_tree(
+	git_reader **out,
+	git_tree *tree);
+
+/**
+ * Create a `git_reader` that will allow random access to the given
+ * index, or the repository's index.
+ *
+ * @param out The reader for the given index
+ * @param repo The repository containing the index
+ * @param index The index to read, or NULL to use the repository's index
+ * @return 0 on success, or an error code < 0
+ */
+extern int git_reader_for_index(
+	git_reader **out,
+	git_repository *repo,
+	git_index *index);
+
+/**
+ * Create a `git_reader` that will allow random access to the given
+ * repository's working directory.  Note that the contents are read
+ * in repository format, meaning any workdir -> odb filters are
+ * applied.
+ *
+ * If `validate_index` is set to true, reads of files will hash the
+ * on-disk contents and ensure that the resulting object ID matches
+ * the repository's index.  This ensures that the working directory
+ * is unmodified from the index contents.
+ *
+ * @param out The reader for the given working directory
+ * @param repo The repository containing the working directory
+ * @param validate_index If true, the working directory contents will
+ *        be compared to the index contents during read to ensure that
+ *        the working directory is unmodified.
+ * @return 0 on success, or an error code < 0
+ */
+extern int git_reader_for_workdir(
+	git_reader **out,
+	git_repository *repo,
+	bool validate_index);
+
+/**
+ * Read the given filename from the reader and populate the given buffer
+ * with the contents and the given oid with the object ID.
+ *
+ * @param out The buffer to populate with the file contents
+ * @param out_id The oid to populate with the object ID
+ * @param reader The reader to read
+ * @param filename The filename to read from the reader
+ */
+extern int git_reader_read(
+	git_buf *out,
+	git_oid *out_id,
+	git_filemode_t *out_filemode,
+	git_reader *reader,
+	const char *filename);
+
+/**
+ * Free the given reader and any associated objects.
+ *
+ * @param reader The reader to free
+ */
+extern void git_reader_free(git_reader *reader);
+
+#endif

tests/apply/callbacks.c

+#include "clar_libgit2.h"
+#include "apply_helpers.h"
+
+static git_repository *repo;
+
+#define TEST_REPO_PATH "merge-recursive"
+
+void test_apply_callbacks__initialize(void)
+{
+	git_oid oid;
+	git_commit *commit;
+
+	repo = cl_git_sandbox_init(TEST_REPO_PATH);
+
+	git_oid_fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
+	cl_git_pass(git_reset(repo, (git_object *)commit, GIT_RESET_HARD, NULL));
+	git_commit_free(commit);
+}
+
+void test_apply_callbacks__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+static int delta_abort_cb(const git_diff_delta *delta, void *payload)
+{
+	GIT_UNUSED(payload);
+
+	if (!strcmp(delta->old_file.path, "veal.txt"))
+		return -99;
+
+	return 0;
+}
+
+void test_apply_callbacks__delta_aborts(void)
+{
+	git_diff *diff;
+	git_apply_options opts = GIT_APPLY_OPTIONS_INIT;
+
+	opts.delta_cb = delta_abort_cb;
+
+	cl_git_pass(git_diff_from_buffer(&diff,
+		DIFF_MODIFY_TWO_FILES, strlen(DIFF_MODIFY_TWO_FILES)));
+	cl_git_fail_with(-99,
+		git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, &opts));
+
+	validate_index_unchanged(repo);
+	validate_workdir_unchanged(repo);
+
+	git_diff_free(diff);
+}
+
+static int delta_skip_cb(const git_diff_delta *delta, void *payload)
+{
+	GIT_UNUSED(payload);
+
+	if (!strcmp(delta->old_file.path, "asparagus.txt"))
+		return 1;
+
+	return 0;
+}
+
+void test_apply_callbacks__delta_can_skip(void)
+{
+	git_diff *diff;
+	git_apply_options opts = GIT_APPLY_OPTIONS_INIT;
+
+	struct merge_index_entry workdir_expected[] = {
+		{ 0100644, "f51658077d85f2264fa179b4d0848268cb3475c3", 0, "asparagus.txt" },
+		{ 0100644, "68f6182f4c85d39e1309d97c7e456156dc9c0096", 0, "beef.txt" },
+		{ 0100644, "4b7c5650008b2e747fe1809eeb5a1dde0e80850a", 0, "bouilli.txt" },
+		{ 0100644, "c4e6cca3ec6ae0148ed231f97257df8c311e015f", 0, "gravy.txt" },
+		{ 0100644, "68af1fc7407fd9addf1701a87eb1c95c7494c598", 0, "oyster.txt" },
+		{ 0100644, "a7b066537e6be7109abfe4ff97b675d4e077da20", 0, "veal.txt" },
+	};
+	size_t workdir_expected_cnt = sizeof(workdir_expected) /
+	    sizeof(struct merge_index_entry);
+
+	opts.delta_cb = delta_skip_cb;
+
+	cl_git_pass(git_diff_from_buffer(&diff,
+		DIFF_MODIFY_TWO_FILES, strlen(DIFF_MODIFY_TWO_FILES)));
+	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, &opts));
+
+	validate_index_unchanged(repo);
+	validate_apply_workdir(repo, workdir_expected, workdir_expected_cnt);
+
+	git_diff_free(diff);
+}
+
+static int hunk_skip_odds_cb(const git_diff_hunk *hunk, void *payload)
+{
+	int *count = (int *)payload;
+	GIT_UNUSED(hunk);
+
+	return ((*count)++ % 2 == 1);
+}
+
+void test_apply_callbacks__hunk_can_skip(void)
+{
+	git_diff *diff;
+	git_apply_options opts = GIT_APPLY_OPTIONS_INIT;
+	int count = 0;
+
+	struct merge_index_entry workdir_expected[] = {
+		{ 0100644, "f51658077d85f2264fa179b4d0848268cb3475c3", 0, "asparagus.txt" },
+		{ 0100644, "68f6182f4c85d39e1309d97c7e456156dc9c0096", 0, "beef.txt" },
+		{ 0100644, "4b7c5650008b2e747fe1809eeb5a1dde0e80850a", 0, "bouilli.txt" },
+		{ 0100644, "c4e6cca3ec6ae0148ed231f97257df8c311e015f", 0, "gravy.txt" },
+		{ 0100644, "68af1fc7407fd9addf1701a87eb1c95c7494c598", 0, "oyster.txt" },
+		{ 0100644, "06f751b6ba4f017ddbf4248015768300268e092a", 0, "veal.txt" },
+	};
+	size_t workdir_expected_cnt = sizeof(workdir_expected) /
+	    sizeof(struct merge_index_entry);
+
+	opts.hunk_cb = hunk_skip_odds_cb;
+	opts.payload = &count;
+
+	cl_git_pass(git_diff_from_buffer(&diff,
+		DIFF_MANY_CHANGES_ONE, strlen(DIFF_MANY_CHANGES_ONE)));
+	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, &opts));
+
+	validate_index_unchanged(repo);
+	validate_apply_workdir(repo, workdir_expected, workdir_expected_cnt);
+
+	git_diff_free(diff);
+}

tests/apply/fromdiff.c

@@ -49,7 +49,7 @@ static int apply_gitbuf(
 		cl_assert_equal_s(patch_expected, patchbuf.ptr);
 	}
 
-	error = git_apply__patch(&result, &filename, &mode, old ? old->ptr : NULL, old ? old->size : 0, patch);
+	error = git_apply__patch(&result, &filename, &mode, old ? old->ptr : NULL, old ? old->size : 0, patch, NULL);
 
 	if (error == 0 && new == NULL) {
 		cl_assert_equal_i(0, result.size);
@@ -150,6 +150,52 @@ void test_apply_fromdiff__prepend_nocontext(void)
 		PATCH_ORIGINAL_TO_PREPEND_NOCONTEXT, &diff_opts));
 }
 
+void test_apply_fromdiff__prepend_and_change(void)
+{
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_PREPEND_AND_CHANGE, "file.txt",
+		PATCH_ORIGINAL_TO_PREPEND_AND_CHANGE, NULL));
+}
+
+void test_apply_fromdiff__prepend_and_change_nocontext(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_PREPEND_AND_CHANGE, "file.txt",
+		PATCH_ORIGINAL_TO_PREPEND_AND_CHANGE_NOCONTEXT, &diff_opts));
+}
+
+void test_apply_fromdiff__delete_and_change(void)
+{
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_DELETE_AND_CHANGE, "file.txt",
+		PATCH_ORIGINAL_TO_DELETE_AND_CHANGE, NULL));
+}
+
+void test_apply_fromdiff__delete_and_change_nocontext(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_DELETE_AND_CHANGE, "file.txt",
+		PATCH_ORIGINAL_TO_DELETE_AND_CHANGE_NOCONTEXT, &diff_opts));
+}
+
+void test_apply_fromdiff__delete_firstline(void)
+{
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_DELETE_FIRSTLINE, "file.txt",
+		PATCH_ORIGINAL_TO_DELETE_FIRSTLINE, NULL));
+}
+
 void test_apply_fromdiff__append(void)
 {
 	cl_git_pass(apply_buf(

tests/apply/fromfile.c

@@ -39,7 +39,7 @@ static int apply_patchfile(
 
 	cl_git_pass(git_patch_from_buffer(&patch, patchfile, strlen(patchfile), NULL));
 
-	error = git_apply__patch(&result, &filename, &mode, old, old_len, patch);
+	error = git_apply__patch(&result, &filename, &mode, old, old_len, patch, NULL);
 
 	if (error == 0) {
 		cl_assert_equal_i(new_len, result.size);

tests/apply/partial.c

+#include "clar_libgit2.h"
+#include "git2/sys/repository.h"
+
+#include "apply.h"
+#include "repository.h"
+#include "buf_text.h"
+
+#include "../patch/patch_common.h"
+
+static git_repository *repo = NULL;
+
+void test_apply_partial__initialize(void)
+{
+	repo = cl_git_sandbox_init("renames");
+}
+
+void test_apply_partial__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+static int skip_addition(
+	const git_diff_hunk *hunk,
+	void *payload)
+{
+	GIT_UNUSED(payload);
+
+	return (hunk->new_lines > hunk->old_lines) ? 1 : 0;
+}
+
+static int skip_deletion(
+	const git_diff_hunk *hunk,
+	void *payload)
+{
+	GIT_UNUSED(payload);
+
+	return (hunk->new_lines < hunk->old_lines) ? 1 : 0;
+}
+
+static int skip_change(
+	const git_diff_hunk *hunk,
+	void *payload)
+{
+	GIT_UNUSED(payload);
+
+	return (hunk->new_lines == hunk->old_lines) ? 1 : 0;
+}
+
+static int abort_addition(
+	const git_diff_hunk *hunk,
+	void *payload)
+{
+	GIT_UNUSED(payload);
+
+	return (hunk->new_lines > hunk->old_lines) ? GIT_EUSER : 0;
+}
+
+static int abort_deletion(
+	const git_diff_hunk *hunk,
+	void *payload)
+{
+	GIT_UNUSED(payload);
+
+	return (hunk->new_lines < hunk->old_lines) ? GIT_EUSER : 0;
+}
+
+static int abort_change(
+	const git_diff_hunk *hunk,
+	void *payload)
+{
+	GIT_UNUSED(payload);
+
+	return (hunk->new_lines == hunk->old_lines) ? GIT_EUSER : 0;
+}
+
+static int apply_buf(
+	const char *old,
+	const char *oldname,
+	const char *new,
+	const char *newname,
+	const char *expected,
+	const git_diff_options *diff_opts,
+	git_apply_hunk_cb hunk_cb,
+	void *payload)
+{
+	git_patch *patch;
+	git_buf result = GIT_BUF_INIT;
+	git_buf patchbuf = GIT_BUF_INIT;
+	git_apply_options opts = GIT_APPLY_OPTIONS_INIT;
+	char *filename;
+	unsigned int mode;
+	int error;
+	size_t oldsize = strlen(old);
+	size_t newsize = strlen(new);
+
+	opts.hunk_cb = hunk_cb;
+	opts.payload = payload;
+
+	cl_git_pass(git_patch_from_buffers(&patch, old, oldsize, oldname, new, newsize, newname, diff_opts));
+	if ((error = git_apply__patch(&result, &filename, &mode, old, oldsize, patch, &opts)) == 0) {
+		cl_assert_equal_s(expected, result.ptr);
+		cl_assert_equal_s(newname, filename);
+		cl_assert_equal_i(0100644, mode);
+	}
+
+	git__free(filename);
+	git_buf_free(&result);
+	git_buf_free(&patchbuf);
+	git_patch_free(patch);
+
+	return error;
+}
+
+void test_apply_partial__prepend_and_change_skip_addition(void)
+{
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_PREPEND_AND_CHANGE, "file.txt",
+		FILE_ORIGINAL, NULL, skip_addition, NULL));
+}
+
+void test_apply_partial__prepend_and_change_nocontext_skip_addition(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_PREPEND_AND_CHANGE, "file.txt",
+		FILE_CHANGE_MIDDLE, &diff_opts, skip_addition, NULL));
+}
+
+void test_apply_partial__prepend_and_change_nocontext_abort_addition(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_fail(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_PREPEND_AND_CHANGE, "file.txt",
+		FILE_ORIGINAL, &diff_opts, abort_addition, NULL));
+}
+
+void test_apply_partial__prepend_and_change_skip_change(void)
+{
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_PREPEND_AND_CHANGE, "file.txt",
+		FILE_PREPEND_AND_CHANGE, NULL, skip_change, NULL));
+}
+
+void test_apply_partial__prepend_and_change_nocontext_skip_change(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_PREPEND_AND_CHANGE, "file.txt",
+		FILE_PREPEND, &diff_opts, skip_change, NULL));
+}
+
+void test_apply_partial__prepend_and_change_nocontext_abort_change(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_fail(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_PREPEND_AND_CHANGE, "file.txt",
+		FILE_PREPEND, &diff_opts, abort_change, NULL));
+}
+
+void test_apply_partial__delete_and_change_skip_deletion(void)
+{
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_DELETE_AND_CHANGE, "file.txt",
+		FILE_ORIGINAL, NULL, skip_deletion, NULL));
+}
+
+void test_apply_partial__delete_and_change_nocontext_skip_deletion(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_DELETE_AND_CHANGE, "file.txt",
+		FILE_CHANGE_MIDDLE, &diff_opts, skip_deletion, NULL));
+}
+
+void test_apply_partial__delete_and_change_nocontext_abort_deletion(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_fail(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_DELETE_AND_CHANGE, "file.txt",
+		FILE_ORIGINAL, &diff_opts, abort_deletion, NULL));
+}
+
+void test_apply_partial__delete_and_change_skip_change(void)
+{
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_DELETE_AND_CHANGE, "file.txt",
+		FILE_DELETE_AND_CHANGE, NULL, skip_change, NULL));
+}
+
+void test_apply_partial__delete_and_change_nocontext_skip_change(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_pass(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_DELETE_AND_CHANGE, "file.txt",
+		FILE_DELETE_FIRSTLINE, &diff_opts, skip_change, NULL));
+}
+
+void test_apply_partial__delete_and_change_nocontext_abort_change(void)
+{
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
+	diff_opts.context_lines = 0;
+
+	cl_git_fail(apply_buf(
+		FILE_ORIGINAL, "file.txt",
+		FILE_DELETE_AND_CHANGE, "file.txt",
+		FILE_DELETE_FIRSTLINE, &diff_opts, abort_change, NULL));
+}

tests/apply/tree.c

+#include "clar_libgit2.h"
+#include "../merge/merge_helpers.h"
+
+static git_repository *repo;
+
+#define TEST_REPO_PATH "merge-recursive"
+
+
+void test_apply_tree__initialize(void)
+{
+	repo = cl_git_sandbox_init(TEST_REPO_PATH);
+}
+
+void test_apply_tree__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+void test_apply_tree__one(void)
+{
+	git_oid a_oid, b_oid;
+	git_commit *a_commit, *b_commit;
+	git_tree *a_tree, *b_tree;
+	git_diff *diff;
+	git_index *index = NULL;
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
+
+	struct merge_index_entry expected[] = {
+		{ 0100644, "ffb36e513f5fdf8a6ba850a20142676a2ac4807d", 0, "asparagus.txt" },
+		{ 0100644, "68f6182f4c85d39e1309d97c7e456156dc9c0096", 0, "beef.txt" },
+		{ 0100644, "4b7c5650008b2e747fe1809eeb5a1dde0e80850a", 0, "bouilli.txt" },
+		{ 0100644, "c4e6cca3ec6ae0148ed231f97257df8c311e015f", 0, "gravy.txt" },
+		{ 0100644, "68af1fc7407fd9addf1701a87eb1c95c7494c598", 0, "oyster.txt" },
+		{ 0100644, "a7b066537e6be7109abfe4ff97b675d4e077da20", 0, "veal.txt" },
+	};
+
+	git_oid_fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	git_oid_fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f");
+
+	cl_git_pass(git_commit_lookup(&a_commit, repo, &a_oid));
+	cl_git_pass(git_commit_lookup(&b_commit, repo, &b_oid));
+
+	cl_git_pass(git_commit_tree(&a_tree, a_commit));
+	cl_git_pass(git_commit_tree(&b_tree, b_commit));
+
+	cl_git_pass(git_diff_tree_to_tree(&diff, repo, a_tree, b_tree, &opts));
+
+	cl_git_pass(git_apply_to_tree(&index, repo, a_tree, diff, NULL));
+	merge_test_index(index, expected, 6);
+
+	git_index_free(index);
+	git_diff_free(diff);
+	git_tree_free(a_tree);
+	git_tree_free(b_tree);
+	git_commit_free(a_commit);
+	git_commit_free(b_commit);
+}
+

tests/iterator/workdir.c

@@ -3,6 +3,7 @@
 #include "repository.h"
 #include "fileops.h"
 #include "../submodule/submodule_helpers.h"
+#include "../merge/merge_helpers.h"
 #include "iterator_helpers.h"
 #include <stdarg.h>
 
@@ -1474,3 +1475,48 @@ void test_iterator_workdir__pathlist_with_directory_include_trees(void)
 	git_vector_free(&filelist);
 }
 
+void test_iterator_workdir__hash_when_requested(void)
+{
+	git_iterator *iter;
+	const git_index_entry *entry;
+	git_iterator_options iter_opts = GIT_ITERATOR_OPTIONS_INIT;
+	git_oid expected_id = {{0}};
+	size_t i;
+
+	struct merge_index_entry expected[] = {
+		{ 0100644, "ffb36e513f5fdf8a6ba850a20142676a2ac4807d", 0, "asparagus.txt" },
+		{ 0100644, "68f6182f4c85d39e1309d97c7e456156dc9c0096", 0, "beef.txt" },
+		{ 0100644, "4b7c5650008b2e747fe1809eeb5a1dde0e80850a", 0, "bouilli.txt" },
+		{ 0100644, "c4e6cca3ec6ae0148ed231f97257df8c311e015f", 0, "gravy.txt" },
+		{ 0100644, "7c7e08f9559d9e1551b91e1cf68f1d0066109add", 0, "oyster.txt" },
+		{ 0100644, "898d12687fb35be271c27c795a6b32c8b51da79e", 0, "veal.txt" },
+	};
+
+	g_repo = cl_git_sandbox_init("merge-recursive");
+
+	/* do the iteration normally, ensure there are no hashes */
+	cl_git_pass(git_iterator_for_workdir(&iter, g_repo, NULL, NULL, &iter_opts));
+
+	for (i = 0; i < sizeof(expected) / sizeof(struct merge_index_entry); i++) {
+		cl_git_pass(git_iterator_advance(&entry, iter));
+
+		cl_assert_equal_oid(&expected_id, &entry->id);
+		cl_assert_equal_s(expected[i].path, entry->path);
+	}
+	cl_assert_equal_i(GIT_ITEROVER, git_iterator_advance(&entry, iter));
+	git_iterator_free(iter);
+
+	/* do the iteration requesting hashes */
+	iter_opts.flags |= GIT_ITERATOR_INCLUDE_HASH;
+	cl_git_pass(git_iterator_for_workdir(&iter, g_repo, NULL, NULL, &iter_opts));
+
+	for (i = 0; i < sizeof(expected) / sizeof(struct merge_index_entry); i++) {
+		cl_git_pass(git_iterator_advance(&entry, iter));
+
+		cl_git_pass(git_oid_fromstr(&expected_id, expected[i].oid_str));
+		cl_assert_equal_oid(&expected_id, &entry->id);
+		cl_assert_equal_s(expected[i].path, entry->path);
+	}
+	cl_assert_equal_i(GIT_ITEROVER, git_iterator_advance(&entry, iter));
+	git_iterator_free(iter);
+}

tests/patch/patch_common.h

@@ -220,6 +220,112 @@
 	"@@ -0,0 +1 @@\n" \
 	"+insert at front\n"
 
+/* An insertion at the beginning of the file and change in the middle */
+
+#define FILE_PREPEND_AND_CHANGE \
+	"insert at front\n" \
+	"hey!\n" \
+	"this is some context!\n" \
+	"around some lines\n" \
+	"that will change\n" \
+	"yes it is!\n" \
+	"(THIS line is changed!)\n" \
+	"and this\n" \
+	"is additional context\n" \
+	"below it!\n"
+
+#define PATCH_ORIGINAL_TO_PREPEND_AND_CHANGE \
+	"diff --git a/file.txt b/file.txt\n" \
+	"index 9432026..f73c8bb 100644\n" \
+	"--- a/file.txt\n" \
+	"+++ b/file.txt\n" \
+	"@@ -1,9 +1,10 @@\n" \
+	"+insert at front\n" \
+	" hey!\n" \
+	" this is some context!\n" \
+	" around some lines\n" \
+	" that will change\n" \
+	" yes it is!\n" \
+	"-(this line is changed)\n" \
+	"+(THIS line is changed!)\n" \
+	" and this\n" \
+	" is additional context\n" \
+	" below it!\n"
+
+#define PATCH_ORIGINAL_TO_PREPEND_AND_CHANGE_NOCONTEXT \
+	"diff --git a/file.txt b/file.txt\n" \
+	"index 9432026..f73c8bb 100644\n" \
+	"--- a/file.txt\n" \
+	"+++ b/file.txt\n" \
+	"@@ -0,0 +1 @@\n" \
+	"+insert at front\n" \
+	"@@ -6 +7 @@ yes it is!\n" \
+	"-(this line is changed)\n" \
+	"+(THIS line is changed!)\n"
+
+/* A deletion at the beginning of the file and a change in the middle */
+
+#define FILE_DELETE_AND_CHANGE \
+	"this is some context!\n" \
+	"around some lines\n" \
+	"that will change\n" \
+	"yes it is!\n" \
+	"(THIS line is changed!)\n" \
+	"and this\n" \
+	"is additional context\n" \
+	"below it!\n"
+
+#define PATCH_ORIGINAL_TO_DELETE_AND_CHANGE \
+	"diff --git a/file.txt b/file.txt\n" \
+	"index 9432026..1e2dfa6 100644\n" \
+	"--- a/file.txt\n" \
+	"+++ b/file.txt\n" \
+	"@@ -1,9 +1,8 @@\n" \
+	"-hey!\n" \
+	" this is some context!\n" \
+	" around some lines\n" \
+	" that will change\n" \
+	" yes it is!\n" \
+	"-(this line is changed)\n" \
+	"+(THIS line is changed!)\n" \
+	" and this\n" \
+	" is additional context\n" \
+	" below it!\n"
+
+#define PATCH_ORIGINAL_TO_DELETE_AND_CHANGE_NOCONTEXT \
+	"diff --git a/file.txt b/file.txt\n" \
+	"index 9432026..1e2dfa6 100644\n" \
+	"--- a/file.txt\n" \
+	"+++ b/file.txt\n" \
+	"@@ -1 +0,0 @@\n" \
+	"-hey!\n" \
+	"@@ -6 +5 @@ yes it is!\n" \
+	"-(this line is changed)\n" \
+	"+(THIS line is changed!)\n"
+
+/* A deletion at the beginning of the file */
+
+#define FILE_DELETE_FIRSTLINE \
+	"this is some context!\n" \
+	"around some lines\n" \
+	"that will change\n" \
+	"yes it is!\n" \
+	"(this line is changed)\n" \
+	"and this\n" \
+	"is additional context\n" \
+	"below it!\n"
+
+#define PATCH_ORIGINAL_TO_DELETE_FIRSTLINE \
+	"diff --git a/file.txt b/file.txt\n" \
+	"index 9432026..f31fa13 100644\n" \
+	"--- a/file.txt\n" \
+	"+++ b/file.txt\n" \
+	"@@ -1,4 +1,3 @@\n" \
+	"-hey!\n" \
+	" this is some context!\n" \
+	" around some lines\n" \
+	" that will change\n"
+
 /* An insertion at the end of the file (and the resultant patch) */
 
 #define FILE_APPEND \