On Fri, Jan 03, 2025 at 11:28:47AM -0800, Wink Saville wrote:
> `git diff-tree --cc` SEGFAUTs after adding trace_printf to diff_tree_combined.
Hmm, is it really a bug in Git if you had to add new code which contains
the bug? :)
> @@ -1595,8 +1597,16 @@ void diff_tree_combined(const struct object_id *oid,
> }
>
> /* find out number of surviving paths */
> - for (num_paths = 0, p = paths; p; p = p->next)
> + trace_printf("Wink diff_tree_combined: find number of surviving paths num_parent=%d\n", num_parent);
> + for (num_paths = 0, p = paths; p; p = p->next) {
> + trace_printf("Wink diff_tree_combined: num_paths=%d &p=%p mode=%0x, oid=%s path=%s\n", num_paths, p, p->mode, oid_to_hex(&p->oid), p->path);
> + for (i = 0; i < num_parent; i++) {
> + trace_printf("Wink diff_tree_combined: &p->parent[%d]=%p status=%c mode=%x oid=%s path.buf=%p contents path.buf=%s\n",
> + i, &p->parent[i], p->parent[i].status, p->parent[i].mode, oid_to_hex(&p->parent[i].oid), p->parent[i].path.buf, p->parent[i].path.buf);
> + }
The parent "path" strbufs are only initialized in intersect_paths() if
combined_all_paths is set, and if there was an actual path change (a
copy or rename).
So you'd probably need something like this:
diff --git a/combine-diff.c b/combine-diff.c
index 455bc19087..1e58809c4e 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -1601,8 +1601,11 @@ void diff_tree_combined(const struct object_id *oid,
for (num_paths = 0, p = paths; p; p = p->next) {
trace_printf("Wink diff_tree_combined: num_paths=%d &p=%p mode=%0x, oid=%s path=%s\n", num_paths, p, p->mode, oid_to_hex(&p->oid), p->path);
for (i = 0; i < num_parent; i++) {
+ const char *path = rev->combine_all_paths &&
+ filename_changed(p->parent[i].status) ?
+ p->parent[i].path.buf : NULL;
trace_printf("Wink diff_tree_combined: &p->parent[%d]=%p status=%c mode=%x oid=%s path.buf=%p contents path.buf=%s\n",
- i, &p->parent[i], p->parent[i].status, p->parent[i].mode, oid_to_hex(&p->parent[i].oid), p->parent[i].path.buf, p->parent[i].path.buf);
+ i, &p->parent[i], p->parent[i].status, p->parent[i].mode, oid_to_hex(&p->parent[i].oid), path, path);
}
num_paths++;
}
-Peff
