From: Elijah Newren <newren@xxxxxxxxx>
Commit 95433eeed9 ("diff: add ability to insert additional headers for
paths", 2022-02-02) introduced the possibility of additional headers,
created in create_filepairs_for_header_only_notifications(). These are
represented by inserting additional pairs in diff_queued_diff which
always have a mode of 0 and a null_oid. When these were added, one
code path was noted to assume that at least one of the diff_filespecs
in the pair were valid, and that codepath was corrected.
The submodule_format handling is another codepath with the same issue;
it would operate on these additional headers and attempt to display them
as submodule changes. Prevent that by explicitly checking for "phoney"
filepairs (i.e. filepairs with both modes being 0).
Reported-by: Philippe Blain <levraiphilippeblain@xxxxxxxxx>
Signed-off-by: Elijah Newren <newren@xxxxxxxxx>
---
diff.c | 29 +++++++++++++++++++++++------
t/t4069-remerge-diff.sh | 8 ++++++++
2 files changed, 31 insertions(+), 6 deletions(-)
diff --git a/diff.c b/diff.c
index 974626a6211..7f8637f3006 100644
--- a/diff.c
+++ b/diff.c
@@ -3398,6 +3398,21 @@ static void add_formatted_headers(struct strbuf *msg,
line_prefix, meta, reset);
}
+static int diff_filepair_is_phoney(struct diff_filespec *one,
+ struct diff_filespec *two)
+{
+ /*
+ * This function specifically looks for pairs injected by
+ * create_filepairs_for_header_only_notifications(). Such
+ * pairs are "phoney" in that they do not represent any
+ * content or even mode difference, but were inserted because
+ * diff_queued_diff previously had no pair associated with
+ * that path but we needed some pair to avoid losing the
+ * "remerge CONFLICT" header associated with the path.
+ */
+ return !DIFF_FILE_VALID(one) && !DIFF_FILE_VALID(two);
+}
+
static void builtin_diff(const char *name_a,
const char *name_b,
struct diff_filespec *one,
@@ -3429,14 +3444,16 @@ static void builtin_diff(const char *name_a,
if (o->submodule_format == DIFF_SUBMODULE_LOG &&
(!one->mode || S_ISGITLINK(one->mode)) &&
- (!two->mode || S_ISGITLINK(two->mode))) {
+ (!two->mode || S_ISGITLINK(two->mode)) &&
+ (!diff_filepair_is_phoney(one, two))) {
show_submodule_diff_summary(o, one->path ? one->path : two->path,
&one->oid, &two->oid,
two->dirty_submodule);
return;
} else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
(!one->mode || S_ISGITLINK(one->mode)) &&
- (!two->mode || S_ISGITLINK(two->mode))) {
+ (!two->mode || S_ISGITLINK(two->mode)) &&
+ (!diff_filepair_is_phoney(one, two))) {
show_submodule_inline_diff(o, one->path ? one->path : two->path,
&one->oid, &two->oid,
two->dirty_submodule);
@@ -3456,12 +3473,12 @@ static void builtin_diff(const char *name_a,
b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
- if (!DIFF_FILE_VALID(one) && !DIFF_FILE_VALID(two)) {
+ if (diff_filepair_is_phoney(one, two)) {
/*
- * We should only reach this point for pairs from
+ * We should only reach this point for pairs generated from
* create_filepairs_for_header_only_notifications(). For
- * these, we should avoid the "/dev/null" special casing
- * above, meaning we avoid showing such pairs as either
+ * these, we want to avoid the "/dev/null" special casing
+ * above, because we do not want such pairs shown as either
* "new file" or "deleted file" below.
*/
lbl[0] = a_one;
diff --git a/t/t4069-remerge-diff.sh b/t/t4069-remerge-diff.sh
index 9e7cac68b1c..e3e6fbd97b2 100755
--- a/t/t4069-remerge-diff.sh
+++ b/t/t4069-remerge-diff.sh
@@ -185,6 +185,14 @@ test_expect_success 'remerge-diff w/ diff-filter=U: all conflict headers, no dif
test_cmp expect actual
'
+test_expect_success 'submodule formatting ignores additional headers' '
+ # Reuses "expect" from last testcase
+
+ git show --oneline --remerge-diff --diff-filter=U --submodule=log >tmp &&
+ sed -e "s/[0-9a-f]\{7,\}/HASH/g" tmp >actual &&
+ test_cmp expect actual
+'
+
test_expect_success 'remerge-diff w/ diff-filter=R: relevant file + conflict header' '
git log -1 --oneline resolution >tmp &&
cat <<-EOF >>tmp &&
--
gitgitgadget
