Fix bug making split deltas a COPIED targets

When FIND_COPIES is used in combination with BREAK_REWRITES for
rename detection, there was a bug where the split MODIFIED delta
was only used as a target for RENAME records and not for COPIED
records.  This fixes that, converting the split into a pair of
DELETED and COPIED deltas when that circumstance arises.

1 files changed, 30 insertions, 16 deletions

diff --git a/src/diff_tform.c b/src/diff_tform.c
index 28a9cc70d..3b5575d28 100644
--- a/src/diff_tform.c
+++ b/src/diff_tform.c
@@ -366,12 +366,28 @@ static int normalize_find_opts(
 	return 0;
 }
 
+static int insert_delete_side_of_split(
+	git_diff *diff, git_vector *onto, const git_diff_delta *delta)
+{
+	/* make new record for DELETED side of split */
+	git_diff_delta *deleted = diff_delta__dup(delta, &diff->pool);
+	GITERR_CHECK_ALLOC(deleted);
+
+	deleted->status = GIT_DELTA_DELETED;
+	deleted->nfiles = 1;
+	memset(&deleted->new_file, 0, sizeof(deleted->new_file));
+	deleted->new_file.path = deleted->old_file.path;
+	deleted->new_file.flags |= GIT_DIFF_FLAG_VALID_OID;
+
+	return git_vector_insert(onto, deleted);
+}
+
 static int apply_splits_and_deletes(
 	git_diff *diff, size_t expected_size, bool actually_split)
 {
 	git_vector onto = GIT_VECTOR_INIT;
 	size_t i;
-	git_diff_delta *delta, *deleted;
+	git_diff_delta *delta;
 
 	if (git_vector_init(&onto, expected_size, git_diff_delta__cmp) < 0)
 		return -1;
@@ -384,17 +400,7 @@ static int apply_splits_and_deletes(
 		if ((delta->flags & GIT_DIFF_FLAG__TO_SPLIT) != 0 && actually_split) {
 			delta->similarity = 0;
 
-			/* make new record for DELETED side of split */
-			if (!(deleted = diff_delta__dup(delta, &diff->pool)))
-				goto on_error;
-
-			deleted->status = GIT_DELTA_DELETED;
-			deleted->nfiles = 1;
-			memset(&deleted->new_file, 0, sizeof(deleted->new_file));
-			deleted->new_file.path = deleted->old_file.path;
-			deleted->new_file.flags |= GIT_DIFF_FLAG_VALID_OID;
-
-			if (git_vector_insert(&onto, deleted) < 0)
+			if (insert_delete_side_of_split(diff, &onto, delta) < 0)
 				goto on_error;
 
 			if (diff->new_src == GIT_ITERATOR_TYPE_WORKDIR)
@@ -1058,10 +1064,7 @@ find_best_matches:
 			}
 		}
 
-		else if (delta_is_new_only(tgt)) {
-			if (!FLAG_SET(&opts, GIT_DIFF_FIND_COPIES))
-				continue;
-
+		else if (FLAG_SET(&opts, GIT_DIFF_FIND_COPIES)) {
 			if (tgt2src_copy[t].similarity < opts.copy_threshold)
 				continue;
 
@@ -1069,10 +1072,21 @@ find_best_matches:
 			best_match = &tgt2src_copy[t];
 			src = GIT_VECTOR_GET(&diff->deltas, best_match->idx);
 
+			if (delta_is_split(tgt)) {
+				error = insert_delete_side_of_split(diff, &diff->deltas, tgt);
+				if (error < 0)
+					goto cleanup;
+				num_rewrites--;
+			}
+
+			if (!delta_is_split(tgt) && !delta_is_new_only(tgt))
+				continue;
+
 			tgt->status     = GIT_DELTA_COPIED;
 			tgt->similarity = best_match->similarity;
 			tgt->nfiles     = 2;
 			memcpy(&tgt->old_file, &src->old_file, sizeof(tgt->old_file));
+			tgt->flags &= ~GIT_DIFF_FLAG__TO_SPLIT;
 
 			num_updates++;
 		}