Fix checkout bug rmv untracked trees from index

When checking out with the GIT_CHECKOUT_REMOVE_UNTRACKED option
and there was an entire tree in the working directory and in the
index that is not in the baseline nor target commit, the tree was
correctly(?) removed from the working directory but was not
successfully removed from the index.  This fixes that and adds a
test of the functionality.

src/checkout.c

@@ -418,6 +418,8 @@ static int checkout_action_with_wd_dir(
 	return checkout_action_common(data, action, delta, wd);
 }
 
+#define EXPAND_DIRS_FOR_STRATEGY (GIT_CHECKOUT_FORCE | GIT_CHECKOUT_REMOVE_UNTRACKED | GIT_CHECKOUT_REMOVE_IGNORED)
+
 static int checkout_action(
 	checkout_data *data,
 	git_diff_delta *delta,
@@ -429,6 +431,7 @@ static int checkout_action(
 	int cmp = -1, act;
 	int (*strcomp)(const char *, const char *) = data->diff->strcomp;
 	int (*pfxcomp)(const char *str, const char *pfx) = data->diff->pfxcomp;
+	bool expand_dirs = (data->strategy & EXPAND_DIRS_FOR_STRATEGY) != 0;
 
 	/* move workdir iterator to follow along with deltas */
 
@@ -449,14 +452,14 @@ static int checkout_action(
 		if (cmp < 0) {
 			cmp = pfxcomp(delta->old_file.path, wd->path);
 
-			if (cmp == 0) {
-				if (wd->mode == GIT_FILEMODE_TREE) {
-					/* case 2 - descend in wd */
+			if (wd->mode == GIT_FILEMODE_TREE && (cmp == 0 || expand_dirs)) {
+				/* case 2 or untracked wd item that might need removal */
 				if (git_iterator_advance_into_directory(workdir, &wd) < 0)
 					goto fail;
 				continue;
 			}
 
+			if (cmp == 0) {
 				/* case 3 -  wd contains non-dir where dir expected */
 				act = checkout_action_with_wd_blocker(data, delta, wd);
 				*wditem_ptr = git_iterator_advance(workdir, &wd) ? NULL : wd;
@@ -519,6 +522,26 @@ fail:
 	return -1;
 }
 
+static int checkout_remaining_wd_items(
+	checkout_data *data,
+	git_iterator *workdir,
+	const git_index_entry *wd,
+	git_vector *spec)
+{
+	int error = 0;
+	bool expand_dirs = (data->strategy & EXPAND_DIRS_FOR_STRATEGY) != 0;
+
+	while (wd && !error) {
+		if (wd->mode == GIT_FILEMODE_TREE && expand_dirs)
+			error = git_iterator_advance_into_directory(workdir, &wd);
+
+		else if (!(error = checkout_action_wd_only(data, workdir, wd, spec)))
+			error = git_iterator_advance(workdir, &wd);
+	}
+
+	return error;
+}
+
 static int checkout_get_actions(
 	uint32_t **actions_ptr,
 	size_t **counts_ptr,
@@ -570,13 +593,9 @@ static int checkout_get_actions(
 			counts[CHECKOUT_ACTION__CONFLICT]++;
 	}
 
-	while (wditem != NULL) {
-		error = checkout_action_wd_only(data, workdir, wditem, &pathspec);
-		if (!error)
-			error = git_iterator_advance(workdir, &wditem);
+	error = checkout_remaining_wd_items(data, workdir, wditem, &pathspec);
 	if (error < 0)
 		goto fail;
-	}
 
 	counts[CHECKOUT_ACTION__REMOVE] += data->removes.length;
 

tests-clar/checkout/head.c

 #include "clar_libgit2.h"
 #include "refs.h"
 #include "repo/repo_helpers.h"
+#include "path.h"
+#include "fileops.h"
 
 static git_repository *g_repo;
 
@@ -20,3 +22,42 @@ void test_checkout_head__orphaned_head_returns_GIT_EORPHANEDHEAD(void)
 
 	cl_assert_equal_i(GIT_EORPHANEDHEAD, git_checkout_head(g_repo, NULL));
 }
+
+void test_checkout_head__with_index_only_tree(void)
+{
+	git_checkout_opts opts = GIT_CHECKOUT_OPTS_INIT;
+	git_index *index;
+
+	/* let's start by getting things into a known state */
+
+	opts.checkout_strategy = GIT_CHECKOUT_FORCE;
+	cl_git_pass(git_checkout_head(g_repo, &opts));
+
+	/* now let's stage some new stuff including a new directory */
+
+	cl_git_pass(git_repository_index(&index, g_repo));
+
+	p_mkdir("testrepo/newdir", 0777);
+    cl_git_mkfile("testrepo/newdir/newfile.txt", "new file\n");
+
+	cl_git_pass(git_index_add_from_workdir(index, "newdir/newfile.txt"));
+	cl_git_pass(git_index_write(index));
+
+	cl_assert(git_path_isfile("testrepo/newdir/newfile.txt"));
+	cl_assert(git_index_get_bypath(index, "newdir/newfile.txt", 0) != NULL);
+
+	git_index_free(index);
+
+	/* okay, so now we have staged this new file; let's see if we can remove */
+
+	opts.checkout_strategy = GIT_CHECKOUT_FORCE | GIT_CHECKOUT_REMOVE_UNTRACKED;
+	cl_git_pass(git_checkout_head(g_repo, &opts));
+
+	cl_git_pass(git_repository_index(&index, g_repo));
+	cl_git_pass(git_index_read(index)); /* reload if needed */
+
+	cl_assert(!git_path_isfile("testrepo/newdir/newfile.txt"));
+	cl_assert(git_index_get_bypath(index, "newdir/newfile.txt", 0) == NULL);
+
+	git_index_free(index);
+}