thodg/libgit2

diff --git a/examples/diff.c b/examples/diff.c
index 31ebf6b..38231d2 100644
--- a/examples/diff.c
+++ b/examples/diff.c
@@ -204,22 +204,22 @@ int main(int argc, char *argv[])
 	/* nothing */
 
 	if (t1 && t2)
-		check(git_diff_tree_to_tree(repo, &opts, t1, t2, &diff), "Diff");
+		check(git_diff_tree_to_tree(&diff, repo, t1, t2, &opts), "Diff");
 	else if (t1 && cached)
-		check(git_diff_index_to_tree(repo, &opts, t1, &diff), "Diff");
+		check(git_diff_index_to_tree(&diff, repo, t1, NULL, &opts), "Diff");
 	else if (t1) {
 		git_diff_list *diff2;
-		check(git_diff_index_to_tree(repo, &opts, t1, &diff), "Diff");
-		check(git_diff_workdir_to_index(repo, &opts, &diff2), "Diff");
+		check(git_diff_index_to_tree(&diff, repo, t1, NULL, &opts), "Diff");
+		check(git_diff_workdir_to_index(&diff2, repo, NULL, &opts), "Diff");
 		check(git_diff_merge(diff, diff2), "Merge diffs");
 		git_diff_list_free(diff2);
 	}
 	else if (cached) {
 		check(resolve_to_tree(repo, "HEAD", &t1), "looking up HEAD");
-		check(git_diff_index_to_tree(repo, &opts, t1, &diff), "Diff");
+		check(git_diff_index_to_tree(&diff, repo, t1, NULL, &opts), "Diff");
 	}
 	else
-		check(git_diff_workdir_to_index(repo, &opts, &diff), "Diff");
+		check(git_diff_workdir_to_index(&diff, repo, NULL, &opts), "Diff");
 
 	if (color >= 0)
 		fputs(colors[0], stdout);
diff --git a/include/git2/checkout.h b/include/git2/checkout.h
index d444450..27ecc71 100644
--- a/include/git2/checkout.h
+++ b/include/git2/checkout.h
@@ -199,13 +199,15 @@ GIT_EXTERN(int) git_checkout_head(
 /**
  * Updates files in the working tree to match the content of the index.
  *
- * @param repo repository to check out (must be non-bare)
+ * @param repo repository into which to check out (must be non-bare)
+ * @param index index to be checked out (or NULL to use repository index)
  * @param opts specifies checkout options (may be NULL)
  * @return 0 on success, GIT_ERROR otherwise (use giterr_last for information
  * about the error)
  */
 GIT_EXTERN(int) git_checkout_index(
 	git_repository *repo,
+	git_index *index,
 	git_checkout_opts *opts);
 
 /**
diff --git a/include/git2/diff.h b/include/git2/diff.h
index a220c2e..3d8e7e7 100644
--- a/include/git2/diff.h
+++ b/include/git2/diff.h
@@ -339,12 +339,14 @@ GIT_EXTERN(int) git_diff_tree_to_tree(
  * @param diff Output pointer to a git_diff_list pointer to be allocated.
  * @param repo The repository containing the tree and index.
  * @param old_tree A git_tree object to diff from.
+ * @param index The index to diff with; repo index used if NULL.
  * @param opts Structure with options to influence diff or NULL for defaults.
  */
 GIT_EXTERN(int) git_diff_index_to_tree(
 	git_diff_list **diff,
 	git_repository *repo,
 	git_tree *old_tree,
+	git_index *index,
 	const git_diff_options *opts); /**< can be NULL for defaults */
 
 /**
@@ -357,11 +359,13 @@ GIT_EXTERN(int) git_diff_index_to_tree(
  *
  * @param diff Output pointer to a git_diff_list pointer to be allocated.
  * @param repo The repository.
+ * @param index The index to diff from; repo index used if NULL.
  * @param opts Structure with options to influence diff or NULL for defaults.
  */
 GIT_EXTERN(int) git_diff_workdir_to_index(
 	git_diff_list **diff,
 	git_repository *repo,
+	git_index *index,
 	const git_diff_options *opts); /**< can be NULL for defaults */
 
 /**
diff --git a/src/checkout.c b/src/checkout.c
index bf1ff4f..03536d4 100644
--- a/src/checkout.c
+++ b/src/checkout.c
@@ -601,12 +601,12 @@ static int checkout_create_submodules(
 
 int git_checkout_index(
 	git_repository *repo,
+	git_index *index,
 	git_checkout_opts *opts)
 {
 	git_diff_list *diff = NULL;
 	git_diff_options diff_opts = {0};
 	git_checkout_opts checkout_opts;
-
 	checkout_diff_data data;
 	git_buf workdir = GIT_BUF_INIT;
 	uint32_t *actions = NULL;
@@ -625,7 +625,7 @@ int git_checkout_index(
 	if (opts && opts->paths.count > 0)
 		diff_opts.pathspec = opts->paths;
 
-	if ((error = git_diff_workdir_to_index(&diff, repo, &diff_opts)) < 0)
+	if ((error = git_diff_workdir_to_index(&diff, repo, index, &diff_opts)) < 0)
 		goto cleanup;
 
 	if ((error = git_buf_puts(&workdir, git_repository_workdir(repo))) < 0)
@@ -706,12 +706,14 @@ int git_checkout_tree(
 		return -1;
 	}
 
+	/* TODO: create a temp index, load tree there and check it out */
+
 	/* load paths in tree that match pathspec into index */
 	if (!(error = git_repository_index(&index, repo)) &&
 		!(error = git_index_read_tree_match(
 			index, tree, opts ? &opts->paths : NULL)) &&
 		!(error = git_index_write(index)))
-		error = git_checkout_index(repo, opts);
+		error = git_checkout_index(repo, NULL, opts);
 
 	git_index_free(index);
 	git_tree_free(tree);
diff --git a/src/diff.c b/src/diff.c
index e6634e6..728e237 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -753,15 +753,13 @@ fail:
 }
 
 
-#define DIFF_FROM_ITERATORS(SETUP, MAKE_FIRST, MAKE_SECOND) \
-	int error; \
+#define DIFF_FROM_ITERATORS(MAKE_FIRST, MAKE_SECOND) do { \
 	git_iterator *a = NULL, *b = NULL; \
 	char *pfx = opts ? git_pathspec_prefix(&opts->pathspec) : NULL; \
-	SETUP; \
     if (!(error = MAKE_FIRST) && !(error = MAKE_SECOND)) \
 		error = diff_from_iterators(diff, repo, a, b, opts); \
 	git__free(pfx); git_iterator_free(a); git_iterator_free(b); \
-    return error
+    } while (0)
 
 int git_diff_tree_to_tree(
 	git_diff_list **diff,
@@ -770,49 +768,59 @@ int git_diff_tree_to_tree(
 	git_tree *new_tree,
 	const git_diff_options *opts)
 {
+	int error = 0;
+
+	assert(diff && repo);
+
 	DIFF_FROM_ITERATORS(
-		assert(repo && old_tree && new_tree && diff),
 		git_iterator_for_tree_range(&a, repo, old_tree, pfx, pfx),
 		git_iterator_for_tree_range(&b, repo, new_tree, pfx, pfx)
 	);
-}
 
-int git_diff__tree_to_index(
-	git_diff_list **diff,
-	git_tree *tree,
-	git_index *index,
-	const git_diff_options *opts)
-{
-	DIFF_FROM_ITERATORS(
-		git_repository *repo = git_index_owner(index),
-	    git_iterator_for_index_range(&a, index, pfx, pfx),
-		git_iterator_for_tree_range(&b, repo, tree, pfx, pfx)
-	);
+	return error;
 }
 
 int git_diff_index_to_tree(
 	git_diff_list **diff,
 	git_repository *repo,
 	git_tree *old_tree,
+	git_index *index,
 	const git_diff_options *opts)
 {
+	int error = 0;
+
+	assert(diff && repo);
+
+	if (!index && (error = git_repository_index__weakptr(&index, repo)) < 0)
+		return error;
+
 	DIFF_FROM_ITERATORS(
-		assert(repo && diff),
 		git_iterator_for_tree_range(&a, repo, old_tree, pfx, pfx),
-	    git_iterator_for_repo_index_range(&b, repo, pfx, pfx)
+	    git_iterator_for_index_range(&b, index, pfx, pfx)
 	);
+
+	return error;
 }
 
 int git_diff_workdir_to_index(
 	git_diff_list **diff,
 	git_repository *repo,
+	git_index *index,
 	const git_diff_options *opts)
 {
+	int error = 0;
+
+	assert(diff && repo);
+
+	if (!index && (error = git_repository_index__weakptr(&index, repo)) < 0)
+		return error;
+
 	DIFF_FROM_ITERATORS(
-		assert(repo && diff),
-		git_iterator_for_repo_index_range(&a, repo, pfx, pfx),
+		git_iterator_for_index_range(&a, index, pfx, pfx),
 	    git_iterator_for_workdir_range(&b, repo, pfx, pfx)
 	);
+
+	return error;
 }
 
 
@@ -822,9 +830,14 @@ int git_diff_workdir_to_tree(
 	git_tree *old_tree,
 	const git_diff_options *opts)
 {
+	int error = 0;
+
+	assert(diff && repo);
+
 	DIFF_FROM_ITERATORS(
-		assert(repo && diff),
 		git_iterator_for_tree_range(&a, repo, old_tree, pfx, pfx),
 	    git_iterator_for_workdir_range(&b, repo, pfx, pfx)
 	);
+
+	return error;
 }
diff --git a/src/diff.h b/src/diff.h
index 3df7ce6..1e3be75 100644
--- a/src/diff.h
+++ b/src/diff.h
@@ -61,11 +61,5 @@ extern bool git_diff_delta__should_skip(
 extern int git_diff__oid_for_file(
 	git_repository *, const char *, uint16_t, git_off_t, git_oid *);
 
-extern int git_diff__tree_to_index(
-	git_diff_list **diff,
-	git_tree *tree,
-	git_index *index,
-	const git_diff_options *opts);
-
 #endif
 
diff --git a/src/reset.c b/src/reset.c
index 69a9c4f..8f470b2 100644
--- a/src/reset.c
+++ b/src/reset.c
@@ -139,7 +139,7 @@ int git_reset(
 	memset(&opts, 0, sizeof(opts));
 	opts.checkout_strategy = GIT_CHECKOUT_FORCE;
 
-	if (git_checkout_index(repo, &opts) < 0) {
+	if (git_checkout_index(repo, NULL, &opts) < 0) {
 		giterr_set(GITERR_INDEX, "%s - Failed to checkout the index.", ERROR_MSG);
 		goto cleanup;
 	}
diff --git a/src/stash.c b/src/stash.c
index 2af3ca9..627d271 100644
--- a/src/stash.c
+++ b/src/stash.c
@@ -322,10 +322,10 @@ static int build_workdir_tree(
 	if (git_commit_tree(&b_tree, b_commit) < 0)
 		goto cleanup;
 
-	if (git_diff_index_to_tree(&diff, repo, b_tree, &opts) < 0)
+	if (git_diff_index_to_tree(&diff, repo, b_tree, NULL, &opts) < 0)
 		goto cleanup;
 
-	if (git_diff_workdir_to_index(&diff2, repo, &opts) < 0)
+	if (git_diff_workdir_to_index(&diff2, repo, NULL, &opts) < 0)
 		goto cleanup;
 
 	if (git_diff_merge(diff, diff2) < 0)
diff --git a/src/status.c b/src/status.c
index 9140ac2..b8c15ef 100644
--- a/src/status.c
+++ b/src/status.c
@@ -142,11 +142,11 @@ int git_status_foreach_ext(
 	/* TODO: support EXCLUDE_SUBMODULES flag */
 
 	if (show != GIT_STATUS_SHOW_WORKDIR_ONLY &&
-		(err = git_diff_index_to_tree(&idx2head, repo, head, &diffopt)) < 0)
+		(err = git_diff_index_to_tree(&idx2head, repo, head, NULL, &diffopt)) < 0)
 		goto cleanup;
 
 	if (show != GIT_STATUS_SHOW_INDEX_ONLY &&
-		(err = git_diff_workdir_to_index(&wd2idx, repo, &diffopt)) < 0)
+		(err = git_diff_workdir_to_index(&wd2idx, repo, NULL, &diffopt)) < 0)
 		goto cleanup;
 
 	usercb.cb = cb;
diff --git a/src/submodule.c b/src/submodule.c
index 527d9e4..6eb1c52 100644
--- a/src/submodule.c
+++ b/src/submodule.c
@@ -1455,7 +1455,7 @@ static int submodule_wd_status(unsigned int *status, git_submodule *sm)
 		if (sm->ignore == GIT_SUBMODULE_IGNORE_NONE)
 			opt.flags |= GIT_DIFF_INCLUDE_UNTRACKED;
 
-		error = git_diff_index_to_tree(&diff, sm_repo, sm_head, &opt);
+		error = git_diff_index_to_tree(&diff, sm_repo, sm_head, NULL, &opt);
 
 		if (!error) {
 			if (git_diff_num_deltas(diff) > 0)
@@ -1472,7 +1472,7 @@ static int submodule_wd_status(unsigned int *status, git_submodule *sm)
 
 		/* perform index-to-workdir diff on submodule */
 
-		error = git_diff_workdir_to_index(&diff, sm_repo, &opt);
+		error = git_diff_workdir_to_index(&diff, sm_repo, NULL, &opt);
 
 		if (!error) {
 			size_t untracked =
diff --git a/tests-clar/checkout/index.c b/tests-clar/checkout/index.c
index 72044d0..c7b19db 100644
--- a/tests-clar/checkout/index.c
+++ b/tests-clar/checkout/index.c
@@ -69,7 +69,7 @@ void test_checkout_index__cannot_checkout_a_bare_repository(void)
 	memset(&g_opts, 0, sizeof(g_opts));
 	g_repo = cl_git_sandbox_init("testrepo.git");
 
-	cl_git_fail(git_checkout_index(g_repo, NULL));
+	cl_git_fail(git_checkout_index(g_repo, NULL, NULL));
 }
 
 void test_checkout_index__can_create_missing_files(void)
@@ -78,7 +78,7 @@ void test_checkout_index__can_create_missing_files(void)
 	cl_assert_equal_i(false, git_path_isfile("./testrepo/branch_file.txt"));
 	cl_assert_equal_i(false, git_path_isfile("./testrepo/new.txt"));
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	test_file_contents("./testrepo/README", "hey there\n");
 	test_file_contents("./testrepo/branch_file.txt", "hi\nbye!\n");
@@ -94,7 +94,7 @@ void test_checkout_index__can_remove_untracked_files(void)
 	cl_assert_equal_i(true, git_path_isdir("./testrepo/dir/subdir/subsubdir"));
 
 	g_opts.checkout_strategy |= GIT_CHECKOUT_REMOVE_UNTRACKED;
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	cl_assert_equal_i(false, git_path_isdir("./testrepo/dir"));
 }
@@ -110,7 +110,7 @@ void test_checkout_index__honor_the_specified_pathspecs(void)
 	cl_assert_equal_i(false, git_path_isfile("./testrepo/branch_file.txt"));
 	cl_assert_equal_i(false, git_path_isfile("./testrepo/new.txt"));
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	cl_assert_equal_i(false, git_path_isfile("./testrepo/README"));
 	test_file_contents("./testrepo/branch_file.txt", "hi\nbye!\n");
@@ -141,7 +141,7 @@ void test_checkout_index__honor_the_gitattributes_directives(void)
 	cl_git_mkfile("./testrepo/.gitattributes", attributes);
 	set_core_autocrlf_to(false);
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	test_file_contents("./testrepo/README", "hey there\n");
 	test_file_contents("./testrepo/new.txt", "my new file\n");
@@ -156,7 +156,7 @@ void test_checkout_index__honor_coreautocrlf_setting_set_to_true(void)
 	cl_git_pass(p_unlink("./testrepo/.gitattributes"));
 	set_core_autocrlf_to(true);
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	test_file_contents("./testrepo/README", expected_readme_text);
 #endif
@@ -171,7 +171,7 @@ void test_checkout_index__honor_coresymlinks_setting_set_to_true(void)
 {
 	set_repo_symlink_handling_cap_to(true);
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 #ifdef GIT_WIN32
 	test_file_contents("./testrepo/link_to_new.txt", "new.txt");
@@ -193,7 +193,7 @@ void test_checkout_index__honor_coresymlinks_setting_set_to_false(void)
 {
 	set_repo_symlink_handling_cap_to(false);
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	test_file_contents("./testrepo/link_to_new.txt", "new.txt");
 }
@@ -207,7 +207,7 @@ void test_checkout_index__donot_overwrite_modified_file_by_default(void)
 	 */
 	g_opts.checkout_strategy = GIT_CHECKOUT_ALLOW_CONFLICTS;
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	test_file_contents("./testrepo/new.txt", "This isn't what's stored!");
 }
@@ -218,7 +218,7 @@ void test_checkout_index__can_overwrite_modified_file(void)
 
 	g_opts.checkout_strategy |= GIT_CHECKOUT_UPDATE_MODIFIED;
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	test_file_contents("./testrepo/new.txt", "my new file\n");
 }
@@ -228,14 +228,14 @@ void test_checkout_index__options_disable_filters(void)
 	cl_git_mkfile("./testrepo/.gitattributes", "*.txt text eol=crlf\n");
 
 	g_opts.disable_filters = false;
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	test_file_contents("./testrepo/new.txt", "my new file\r\n");
 
 	p_unlink("./testrepo/new.txt");
 
 	g_opts.disable_filters = true;
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	test_file_contents("./testrepo/new.txt", "my new file\n");
 }
@@ -253,7 +253,7 @@ void test_checkout_index__options_dir_modes(void)
 	reset_index_to_treeish((git_object *)commit);
 
 	g_opts.dir_mode = 0701;
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	cl_git_pass(p_stat("./testrepo/a", &st));
 	cl_assert_equal_i(st.st_mode & 0777, 0701);
@@ -273,7 +273,7 @@ void test_checkout_index__options_override_file_modes(void)
 
 	g_opts.file_mode = 0700;
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	cl_git_pass(p_stat("./testrepo/new.txt", &st));
 	cl_assert_equal_i(st.st_mode & 0777, 0700);
@@ -287,7 +287,7 @@ void test_checkout_index__options_open_flags(void)
 	g_opts.file_open_flags = O_CREAT | O_RDWR | O_APPEND;
 
 	g_opts.checkout_strategy |= GIT_CHECKOUT_UPDATE_MODIFIED;
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	test_file_contents("./testrepo/new.txt", "hi\nmy new file\n");
 }
@@ -334,7 +334,7 @@ void test_checkout_index__can_notify_of_skipped_files(void)
 	g_opts.conflict_cb = conflict_cb;
 	g_opts.conflict_payload = &data;
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 }
 
 static int dont_conflict_cb(
@@ -366,7 +366,7 @@ void test_checkout_index__wont_notify_of_expected_line_ending_changes(void)
 	g_opts.conflict_cb = dont_conflict_cb;
 	g_opts.conflict_payload = NULL;
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 }
 
 static void progress(const char *path, size_t cur, size_t tot, void *payload)
@@ -382,7 +382,7 @@ void test_checkout_index__calls_progress_callback(void)
 	g_opts.progress_cb = progress;
 	g_opts.progress_payload = &was_called;
 
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 	cl_assert_equal_i(was_called, true);
 }
 
@@ -413,13 +413,13 @@ void test_checkout_index__can_overcome_name_clashes(void)
 	cl_assert(git_path_isfile("./testrepo/path0/file0"));
 
 	g_opts.checkout_strategy = GIT_CHECKOUT_SAFE | GIT_CHECKOUT_ALLOW_CONFLICTS;
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	cl_assert(git_path_isfile("./testrepo/path1"));
 	cl_assert(git_path_isfile("./testrepo/path0/file0"));
 
 	g_opts.checkout_strategy = GIT_CHECKOUT_FORCE;
-	cl_git_pass(git_checkout_index(g_repo, &g_opts));
+	cl_git_pass(git_checkout_index(g_repo, NULL, &g_opts));
 
 	cl_assert(git_path_isfile("./testrepo/path0"));
 	cl_assert(git_path_isfile("./testrepo/path1/file1"));
diff --git a/tests-clar/diff/diffiter.c b/tests-clar/diff/diffiter.c
index f021d46..133392c 100644
--- a/tests-clar/diff/diffiter.c
+++ b/tests-clar/diff/diffiter.c
@@ -16,7 +16,7 @@ void test_diff_diffiter__create(void)
 	git_diff_list *diff;
 	size_t d, num_d;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL));
+	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL, NULL));
 
 	num_d = git_diff_num_deltas(diff);
 	for (d = 0; d < num_d; ++d) {
@@ -34,7 +34,7 @@ void test_diff_diffiter__iterate_files(void)
 	size_t d, num_d;
 	int count = 0;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL));
+	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL, NULL));
 
 	num_d = git_diff_num_deltas(diff);
 	cl_assert_equal_i(6, (int)num_d);
@@ -57,7 +57,7 @@ void test_diff_diffiter__iterate_files_2(void)
 	size_t d, num_d;
 	int count = 0;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL));
+	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL, NULL));
 
 	num_d = git_diff_num_deltas(diff);
 	cl_assert_equal_i(8, (int)num_d);
@@ -85,7 +85,7 @@ void test_diff_diffiter__iterate_files_and_hunks(void)
 	opts.interhunk_lines = 1;
 	opts.flags |= GIT_DIFF_INCLUDE_IGNORED | GIT_DIFF_INCLUDE_UNTRACKED;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL, &opts));
 
 	num_d = git_diff_num_deltas(diff);
 
@@ -138,7 +138,7 @@ void test_diff_diffiter__max_size_threshold(void)
 	opts.interhunk_lines = 1;
 	opts.flags |= GIT_DIFF_INCLUDE_IGNORED | GIT_DIFF_INCLUDE_UNTRACKED;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL, &opts));
 	num_d = git_diff_num_deltas(diff);
 
 	for (d = 0; d < num_d; ++d) {
@@ -173,7 +173,7 @@ void test_diff_diffiter__max_size_threshold(void)
 	opts.flags |= GIT_DIFF_INCLUDE_IGNORED | GIT_DIFF_INCLUDE_UNTRACKED;
 	opts.max_size = 50; /* treat anything over 50 bytes as binary! */
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL, &opts));
 	num_d = git_diff_num_deltas(diff);
 
 	for (d = 0; d < num_d; ++d) {
@@ -216,7 +216,7 @@ void test_diff_diffiter__iterate_all(void)
 	opts.interhunk_lines = 1;
 	opts.flags |= GIT_DIFF_INCLUDE_IGNORED | GIT_DIFF_INCLUDE_UNTRACKED;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL, &opts));
 
 	num_d = git_diff_num_deltas(diff);
 	for (d = 0; d < num_d; ++d) {
@@ -292,7 +292,7 @@ void test_diff_diffiter__iterate_randomly_while_saving_state(void)
 	opts.interhunk_lines = 1;
 	opts.flags |= GIT_DIFF_INCLUDE_IGNORED | GIT_DIFF_INCLUDE_UNTRACKED;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL, &opts));
 
 	num_d = git_diff_num_deltas(diff);
 
@@ -419,7 +419,7 @@ void test_diff_diffiter__iterate_and_generate_patch_text(void)
 	git_diff_list *diff;
 	size_t d, num_d;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL));
+	cl_git_pass(git_diff_workdir_to_index(&diff, repo, NULL, NULL));
 
 	num_d = git_diff_num_deltas(diff);
 	cl_assert_equal_i(8, (int)num_d);
diff --git a/tests-clar/diff/index.c b/tests-clar/diff/index.c
index dede941..4b96bfa 100644
--- a/tests-clar/diff/index.c
+++ b/tests-clar/diff/index.c
@@ -32,7 +32,7 @@ void test_diff_index__0(void)
 
 	memset(&exp, 0, sizeof(exp));
 
-	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, a, &opts));
+	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, a, NULL, &opts));
 
 	cl_git_pass(git_diff_foreach(
 		diff, &exp, diff_file_fn, diff_hunk_fn, diff_line_fn));
@@ -60,7 +60,7 @@ void test_diff_index__0(void)
 	diff = NULL;
 	memset(&exp, 0, sizeof(exp));
 
-	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, b, &opts));
+	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, b, NULL, &opts));
 
 	cl_git_pass(git_diff_foreach(
 		diff, &exp, diff_file_fn, diff_hunk_fn, diff_line_fn));
@@ -125,7 +125,7 @@ void test_diff_index__1(void)
 
 	memset(&exp, 0, sizeof(exp));
 
-	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, a, &opts));
+	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, a, NULL, &opts));
 
 	cl_assert_equal_i(
 		GIT_EUSER,
diff --git a/tests-clar/diff/workdir.c b/tests-clar/diff/workdir.c
index 8de68e5..a4dbe37 100644
--- a/tests-clar/diff/workdir.c
+++ b/tests-clar/diff/workdir.c
@@ -26,7 +26,7 @@ void test_diff_workdir__to_index(void)
 	opts.interhunk_lines = 1;
 	opts.flags |= GIT_DIFF_INCLUDE_IGNORED | GIT_DIFF_INCLUDE_UNTRACKED;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -127,8 +127,8 @@ void test_diff_workdir__to_tree(void)
 	 * a workdir to tree diff (even though it is not really).  This is what
 	 * you would get from "git diff --name-status 26a125ee1bf"
 	 */
-	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, a, &opts));
-	cl_git_pass(git_diff_workdir_to_index(&diff2, g_repo, &opts));
+	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, a, NULL, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff2, g_repo, NULL, &opts));
 	cl_git_pass(git_diff_merge(diff, diff2));
 	git_diff_list_free(diff2);
 
@@ -164,8 +164,8 @@ void test_diff_workdir__to_tree(void)
 	/* Again, emulating "git diff <sha>" for testing purposes using
 	 * "git diff --name-status 0017bd4ab1ec3" instead.
 	 */
-	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, b, &opts));
-	cl_git_pass(git_diff_workdir_to_index(&diff2, g_repo, &opts));
+	cl_git_pass(git_diff_index_to_tree(&diff, g_repo, b, NULL, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff2, g_repo, NULL, &opts));
 	cl_git_pass(git_diff_merge(diff, diff2));
 	git_diff_list_free(diff2);
 
@@ -216,7 +216,7 @@ void test_diff_workdir__to_index_with_pathspec(void)
 	opts.pathspec.strings = &pathspec;
 	opts.pathspec.count   = 1;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -239,7 +239,7 @@ void test_diff_workdir__to_index_with_pathspec(void)
 
 	pathspec = "modified_file";
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -262,7 +262,7 @@ void test_diff_workdir__to_index_with_pathspec(void)
 
 	pathspec = "subdir";
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -285,7 +285,7 @@ void test_diff_workdir__to_index_with_pathspec(void)
 
 	pathspec = "*_deleted";
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -324,7 +324,7 @@ void test_diff_workdir__filemode_changes(void)
 
 	/* test once with no mods */
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, NULL));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -347,7 +347,7 @@ void test_diff_workdir__filemode_changes(void)
 
 	cl_assert(cl_toggle_filemode("issue_592/a.txt"));
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, NULL));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -386,7 +386,7 @@ void test_diff_workdir__filemode_changes_with_filemode_false(void)
 
 	/* test once with no mods */
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, NULL));
 
 	memset(&exp, 0, sizeof(exp));
 	cl_git_pass(git_diff_foreach(
@@ -402,7 +402,7 @@ void test_diff_workdir__filemode_changes_with_filemode_false(void)
 
 	cl_assert(cl_toggle_filemode("issue_592/a.txt"));
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, NULL));
 
 	memset(&exp, 0, sizeof(exp));
 	cl_git_pass(git_diff_foreach(
@@ -442,8 +442,8 @@ void test_diff_workdir__head_index_and_workdir_all_differ(void)
 	opts.pathspec.strings = &pathspec;
 	opts.pathspec.count   = 1;
 
-	cl_git_pass(git_diff_index_to_tree(&diff_i2t, g_repo, tree, &opts));
-	cl_git_pass(git_diff_workdir_to_index(&diff_w2i, g_repo, &opts));
+	cl_git_pass(git_diff_index_to_tree(&diff_i2t, g_repo, tree, NULL, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff_w2i, g_repo, NULL, &opts));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -529,7 +529,7 @@ void test_diff_workdir__eof_newline_changes(void)
 	opts.pathspec.strings = &pathspec;
 	opts.pathspec.count   = 1;
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -556,7 +556,7 @@ void test_diff_workdir__eof_newline_changes(void)
 
 	cl_git_append2file("status/current_file", "\n");
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -583,7 +583,7 @@ void test_diff_workdir__eof_newline_changes(void)
 
 	cl_git_rewritefile("status/current_file", "current_file");
 
-	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, &opts));
+	cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 
 	for (use_iterator = 0; use_iterator <= 1; use_iterator++) {
 		memset(&exp, 0, sizeof(exp));
@@ -699,7 +699,7 @@ void test_diff_workdir__larger_hunks(void)
 		/* okay, this is a bit silly, but oh well */
 		switch (i) {
 		case 0:
-			cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, &opts));
+			cl_git_pass(git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 			break;
 		case 1:
 			cl_git_pass(git_diff_workdir_to_tree(&diff, g_repo, a, &opts));
@@ -829,7 +829,7 @@ void test_diff_workdir__cannot_diff_against_a_bare_repository(void)
 	g_repo = cl_git_sandbox_init("testrepo.git");
 
 	cl_assert_equal_i(
-		GIT_EBAREREPO, git_diff_workdir_to_index(&diff, g_repo, &opts));
+		GIT_EBAREREPO, git_diff_workdir_to_index(&diff, g_repo, NULL, &opts));
 
 	cl_git_pass(git_repository_head_tree(&tree, g_repo));