patch printing: include rename information

src/diff_print.c

@@ -322,6 +322,26 @@ static int diff_delta_format_with_paths(
 	return git_buf_printf(out, template, oldpfx, oldpath, newpfx, newpath);
 }
 
+int diff_delta_format_rename_header(
+	git_buf *out,
+	const git_diff_delta *delta)
+{
+	if (delta->similarity > 100) {
+		giterr_set(GITERR_PATCH, "invalid similarity %d", delta->similarity);
+		return -1;
+	}
+
+	git_buf_printf(out,
+		"similarity index %d%%\n"
+		"rename from %s\n"
+		"rename to %s\n",
+		delta->similarity,
+		delta->old_file.path,
+		delta->new_file.path);
+
+	return git_buf_oom(out) ? -1 : 0;
+}
+
 int git_diff_delta__format_file_header(
 	git_buf *out,
 	const git_diff_delta *delta,
@@ -341,6 +361,9 @@ int git_diff_delta__format_file_header(
 	git_buf_printf(out, "diff --git %s%s %s%s\n",
 		oldpfx, delta->old_file.path, newpfx, delta->new_file.path);
 
+	if (delta->status == GIT_DELTA_RENAMED)
+		GITERR_CHECK_ERROR(diff_delta_format_rename_header(out, delta));
+
 	GITERR_CHECK_ERROR(diff_print_oid_range(out, delta, oid_strlen));
 
 	if ((delta->flags & GIT_DIFF_FLAG_BINARY) == 0)

src/patch_parse.c

@@ -306,7 +306,7 @@ static int parse_header_rename(
 static int parse_header_renamefrom(
 	git_patch_parsed *patch, patch_parse_ctx *ctx)
 {
-	patch->base.delta->status |= GIT_DELTA_RENAMED;
+	patch->base.delta->status = GIT_DELTA_RENAMED;
 
 	return parse_header_rename(
 		(char **)&patch->base.delta->old_file.path,
@@ -317,7 +317,7 @@ static int parse_header_renamefrom(
 static int parse_header_renameto(
 	git_patch_parsed *patch, patch_parse_ctx *ctx)
 {
-	patch->base.delta->status |= GIT_DELTA_RENAMED;
+	patch->base.delta->status = GIT_DELTA_RENAMED;
 
 	return parse_header_rename(
 		(char **)&patch->base.delta->new_file.path,