thodg/libgit2

diff --git a/include/git2/tree.h b/include/git2/tree.h
index 2d3534f..b3c22e7 100644
--- a/include/git2/tree.h
+++ b/include/git2/tree.h
@@ -81,6 +81,14 @@ GIT_INLINE(void) git_tree_free(git_tree *tree)
 GIT_EXTERN(const git_oid *) git_tree_id(const git_tree *tree);
 
 /**
+ * Get the repository that contains the tree.
+ *
+ * @param tree A previously loaded tree.
+ * @return Repository that contains this tree.
+ */
+GIT_EXTERN(git_repository *) git_tree_owner(const git_tree *tree);
+
+/**
  * Get the number of entries listed in a tree
  *
  * @param tree a previously loaded tree.
diff --git a/src/checkout.c b/src/checkout.c
index 33de7ad..d9f0f8f 100644
--- a/src/checkout.c
+++ b/src/checkout.c
@@ -448,8 +448,7 @@ static int checkout_get_actions(
 		!(error == GIT_ENOTFOUND || error == GIT_EORPHANEDHEAD))
 			return -1;
 
-	if ((error = git_iterator_for_tree_range(
-			 &hiter, data->repo, head, pfx, pfx)) < 0)
+	if ((error = git_iterator_for_tree_range(&hiter, head, pfx, pfx)) < 0)
 		goto fail;
 
 	if ((diff->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE) != 0 &&
diff --git a/src/diff.c b/src/diff.c
index c4bfc36..822ae5b 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -570,7 +570,7 @@ static int diff_list_init_from_iterators(
 	return 0;
 }
 
-static int diff_from_iterators(
+int git_diff__from_iterators(
 	git_diff_list **diff_ptr,
 	git_repository *repo,
 	git_iterator *old_iter,
@@ -610,9 +610,10 @@ static int diff_from_iterators(
 
 	/* run iterators building diffs */
 	while (oitem || nitem) {
+		int cmp = oitem ? (nitem ? diff->entrycomp(oitem, nitem) : -1) : 1;
 
 		/* create DELETED records for old items not matched in new */
-		if (oitem && (!nitem || diff->entrycomp(oitem, nitem) < 0)) {
+		if (cmp < 0) {
 			if (diff_delta__from_one(diff, GIT_DELTA_DELETED, oitem) < 0)
 				goto fail;
 
@@ -637,7 +638,7 @@ static int diff_from_iterators(
 		/* create ADDED, TRACKED, or IGNORED records for new items not
 		 * matched in old (and/or descend into directories as needed)
 		 */
-		else if (nitem && (!oitem || diff->entrycomp(oitem, nitem) > 0)) {
+		else if (cmp > 0) {
 			git_delta_t delta_type = GIT_DELTA_UNTRACKED;
 
 			/* check if contained in ignored parent directory */
@@ -733,7 +734,7 @@ static int diff_from_iterators(
 		 * (or ADDED and DELETED pair if type changed)
 		 */
 		else {
-			assert(oitem && nitem && diff->entrycomp(oitem, nitem) == 0);
+			assert(oitem && nitem && cmp == 0);
 
 			if (maybe_modified(old_iter, oitem, new_iter, nitem, diff) < 0 ||
 				git_iterator_advance(old_iter, &oitem) < 0 ||
@@ -759,8 +760,8 @@ fail:
 	git_iterator *a = NULL, *b = NULL; \
 	char *pfx = opts ? git_pathspec_prefix(&opts->pathspec) : NULL; \
 	GITERR_CHECK_VERSION(opts, GIT_DIFF_OPTIONS_VERSION, "git_diff_options"); \
-	if (!(error = MAKE_FIRST) && !(error = MAKE_SECOND)) \
-		error = diff_from_iterators(diff, repo, a, b, opts); \
+    if (!(error = MAKE_FIRST) && !(error = MAKE_SECOND)) \
+		error = git_diff__from_iterators(diff, repo, a, b, opts); \
 	git__free(pfx); git_iterator_free(a); git_iterator_free(b); \
 } while (0)
 
@@ -776,8 +777,8 @@ int git_diff_tree_to_tree(
 	assert(diff && repo);
 
 	DIFF_FROM_ITERATORS(
-		git_iterator_for_tree_range(&a, repo, old_tree, pfx, pfx),
-		git_iterator_for_tree_range(&b, repo, new_tree, pfx, pfx)
+		git_iterator_for_tree_range(&a, old_tree, pfx, pfx),
+		git_iterator_for_tree_range(&b, new_tree, pfx, pfx)
 	);
 
 	return error;
@@ -798,7 +799,7 @@ int git_diff_index_to_tree(
 		return error;
 
 	DIFF_FROM_ITERATORS(
-		git_iterator_for_tree_range(&a, repo, old_tree, pfx, pfx),
+		git_iterator_for_tree_range(&a, old_tree, pfx, pfx),
 	    git_iterator_for_index_range(&b, index, pfx, pfx)
 	);
 
@@ -838,7 +839,7 @@ int git_diff_workdir_to_tree(
 	assert(diff && repo);
 
 	DIFF_FROM_ITERATORS(
-		git_iterator_for_tree_range(&a, repo, old_tree, pfx, pfx),
+		git_iterator_for_tree_range(&a, old_tree, pfx, pfx),
 	    git_iterator_for_workdir_range(&b, repo, pfx, pfx)
 	);
 
diff --git a/src/diff.h b/src/diff.h
index f93bab1..8f5ea34 100644
--- a/src/diff.h
+++ b/src/diff.h
@@ -61,6 +61,12 @@ 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__from_iterators(
+	git_diff_list **diff_ptr,
+	git_repository *repo,
+	git_iterator *old_iter,
+	git_iterator *new_iter,
+	const git_diff_options *opts);
 
 #endif
 
diff --git a/src/index.c b/src/index.c
index f3ced9e..1e5b280 100644
--- a/src/index.c
+++ b/src/index.c
@@ -1641,8 +1641,7 @@ int git_index_read_tree_match(
 
 	pfx = git_pathspec_prefix(strspec);
 
-	if ((error = git_iterator_for_tree_range(
-			 &iter, INDEX_OWNER(index), tree, pfx, pfx)) < 0 ||
+	if ((error = git_iterator_for_tree_range(&iter, tree, pfx, pfx)) < 0 ||
 		(error = git_iterator_current(iter, &entry)) < 0)
 		goto cleanup;
 
diff --git a/src/iterator.c b/src/iterator.c
index 0fdf0c6..e2bf4cf 100644
--- a/src/iterator.c
+++ b/src/iterator.c
@@ -18,7 +18,7 @@
 	(P)->base.type    = GIT_ITERATOR_ ## NAME_UC; \
 	(P)->base.start   = start ? git__strdup(start) : NULL; \
 	(P)->base.end     = end ? git__strdup(end) : NULL; \
-	(P)->base.ignore_case = 0; \
+	(P)->base.ignore_case = false; \
 	(P)->base.current = NAME_LC ## _iterator__current; \
 	(P)->base.at_end  = NAME_LC ## _iterator__at_end; \
 	(P)->base.advance = NAME_LC ## _iterator__advance; \
@@ -91,7 +91,6 @@ struct tree_iterator_frame {
 
 typedef struct {
 	git_iterator base;
-	git_repository *repo;
 	tree_iterator_frame *stack, *tail;
 	git_index_entry entry;
 	git_buf path;
@@ -205,7 +204,7 @@ static int tree_iterator__expand_tree(tree_iterator *ti)
 			git__prefixcmp(ti->path.ptr, ti->base.end) > 0)
 			return tree_iterator__to_end(ti);
 
-		if ((error = git_tree_lookup(&subtree, ti->repo, &te->oid)) < 0)
+		if ((error = git_tree_lookup(&subtree, ti->base.repo, &te->oid)) < 0)
 			return error;
 
 		relpath = NULL;
@@ -302,7 +301,6 @@ static int tree_iterator__reset(git_iterator *self)
 
 int git_iterator_for_tree_range(
 	git_iterator **iter,
-	git_repository *repo,
 	git_tree *tree,
 	const char *start,
 	const char *end)
@@ -315,7 +313,7 @@ int git_iterator_for_tree_range(
 
 	ITERATOR_BASE_INIT(ti, tree, TREE);
 
-	ti->repo  = repo;
+	ti->base.repo = git_tree_owner(tree);
 	ti->stack = ti->tail = tree_iterator__alloc_frame(tree, ti->base.start);
 
 	if ((error = tree_iterator__expand_tree(ti)) < 0)
@@ -424,6 +422,7 @@ int git_iterator_for_index_range(
 	ITERATOR_BASE_INIT(ii, index, INDEX);
 
 	ii->index = index;
+	ii->base.repo = git_index_owner(index);
 	ii->base.ignore_case = ii->index->ignore_case;
 
 	index_iterator__reset((git_iterator *)ii);
@@ -461,7 +460,6 @@ struct workdir_iterator_frame {
 
 typedef struct {
 	git_iterator base;
-	git_repository *repo;
 	size_t root_len;
 	workdir_iterator_frame *stack;
 	git_ignores ignores;
@@ -716,7 +714,7 @@ static int workdir_iterator__update_entry(workdir_iterator *wi)
 
 	/* detect submodules */
 	if (S_ISDIR(wi->entry.mode)) {
-		int res = git_submodule_lookup(NULL, wi->repo, wi->entry.path);
+		int res = git_submodule_lookup(NULL, wi->base.repo, wi->entry.path);
 		bool is_submodule = (res == 0);
 		if (res == GIT_ENOTFOUND)
 			giterr_clear();
@@ -750,7 +748,7 @@ int git_iterator_for_workdir_range(
 		return error;
 
 	ITERATOR_BASE_INIT(wi, workdir, WORKDIR);
-	wi->repo = repo;
+	wi->base.repo = repo;
 
 	if ((error = git_repository_index__weakptr(&index, repo)) < 0) {
 		git__free(wi);
diff --git a/src/iterator.h b/src/iterator.h
index 77ead76..07cce5a 100644
--- a/src/iterator.h
+++ b/src/iterator.h
@@ -28,32 +28,33 @@ typedef enum {
 
 struct git_iterator {
 	git_iterator_type_t type;
+	git_repository *repo;
 	char *start;
 	char *end;
+	bool ignore_case;
+
 	int (*current)(git_iterator *, const git_index_entry **);
 	int (*at_end)(git_iterator *);
 	int (*advance)(git_iterator *, const git_index_entry **);
 	int (*seek)(git_iterator *, const char *prefix);
 	int (*reset)(git_iterator *);
 	void (*free)(git_iterator *);
-	unsigned int ignore_case:1;
 };
 
 extern int git_iterator_for_nothing(git_iterator **iter);
 
 extern int git_iterator_for_tree_range(
-	git_iterator **iter, git_repository *repo, git_tree *tree,
+	git_iterator **iter, git_tree *tree,
 	const char *start, const char *end);
 
 GIT_INLINE(int) git_iterator_for_tree(
-	git_iterator **iter, git_repository *repo, git_tree *tree)
+	git_iterator **iter, git_tree *tree)
 {
-	return git_iterator_for_tree_range(iter, repo, tree, NULL, NULL);
+	return git_iterator_for_tree_range(iter, tree, NULL, NULL);
 }
 
 extern int git_iterator_for_index_range(
-	git_iterator **iter, git_index *index,
-	const char *start, const char *end);
+	git_iterator **iter, git_index *index, const char *start, const char *end);
 
 GIT_INLINE(int) git_iterator_for_index(
 	git_iterator **iter, git_index *index)
@@ -90,7 +91,8 @@ GIT_INLINE(int) git_iterator_spoolandsort(
 	git_iterator **iter, git_iterator *towrap,
 	git_vector_cmp comparer, bool ignore_case)
 {
-	return git_iterator_spoolandsort_range(iter, towrap, comparer, ignore_case, NULL, NULL);
+	return git_iterator_spoolandsort_range(
+		iter, towrap, comparer, ignore_case, NULL, NULL);
 }
 
 /* Entry is not guaranteed to be fully populated.  For a tree iterator,
@@ -149,6 +151,11 @@ GIT_INLINE(git_iterator_type_t) git_iterator_type(git_iterator *iter)
 	return iter->type;
 }
 
+GIT_INLINE(git_repository *) git_iterator_owner(git_iterator *iter)
+{
+	return iter->repo;
+}
+
 extern int git_iterator_current_tree_entry(
 	git_iterator *iter, const git_tree_entry **tree_entry);
 
diff --git a/src/notes.c b/src/notes.c
index f96b5b1..8a27bdb 100644
--- a/src/notes.c
+++ b/src/notes.c
@@ -593,7 +593,7 @@ int git_note_foreach(
 
 	if (!(error = retrieve_note_tree_and_commit(
 			&tree, &commit, repo, &notes_ref)) &&
-		!(error = git_iterator_for_tree(&iter, repo, tree)))
+		!(error = git_iterator_for_tree(&iter, tree)))
 		error = git_iterator_current(iter, &item);
 
 	while (!error && item) {
diff --git a/src/submodule.c b/src/submodule.c
index 21a1875..3d9950d 100644
--- a/src/submodule.c
+++ b/src/submodule.c
@@ -1156,7 +1156,7 @@ static int load_submodule_config_from_head(
 	if ((error = git_repository_head_tree(&head, repo)) < 0)
 		return error;
 
-	if ((error = git_iterator_for_tree(&i, repo, head)) < 0) {
+	if ((error = git_iterator_for_tree(&i, head)) < 0) {
 		git_tree_free(head);
 		return error;
 	}
diff --git a/src/tree.c b/src/tree.c
index efb991d..944992f 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -207,9 +207,14 @@ void git_tree__free(git_tree *tree)
 	git__free(tree);
 }
 
-const git_oid *git_tree_id(const git_tree *c)
+const git_oid *git_tree_id(const git_tree *t)
 {
-	return git_object_id((const git_object *)c);
+	return git_object_id((const git_object *)t);
+}
+
+git_repository *git_tree_owner(const git_tree *t)
+{
+	return git_object_owner((const git_object *)t);
 }
 
 git_filemode_t git_tree_entry_filemode(const git_tree_entry *entry)
diff --git a/tests-clar/diff/iterator.c b/tests-clar/diff/iterator.c
index 1d83960..c97e09a 100644
--- a/tests-clar/diff/iterator.c
+++ b/tests-clar/diff/iterator.c
@@ -35,7 +35,7 @@ static void tree_iterator_test(
 	git_repository *repo = cl_git_sandbox_init(sandbox);
 
 	cl_assert(t = resolve_commit_oid_to_tree(repo, treeish));
-	cl_git_pass(git_iterator_for_tree_range(&i, repo, t, start, end));
+	cl_git_pass(git_iterator_for_tree_range(&i, t, start, end));
 	cl_git_pass(git_iterator_current(i, &entry));
 
 	while (entry != NULL) {
@@ -294,7 +294,7 @@ void test_diff_iterator__tree_special_functions(void)
 		repo, "24fa9a9fc4e202313e24b648087495441dab432b");
 	cl_assert(t != NULL);
 
-	cl_git_pass(git_iterator_for_tree_range(&i, repo, t, NULL, NULL));
+	cl_git_pass(git_iterator_for_tree_range(&i, t, NULL, NULL));
 	cl_git_pass(git_iterator_current(i, &entry));
 
 	while (entry != NULL) {