Hi Thomas,
On Mon, 7 Oct 2019, Thomas Gummerer wrote:
> Subject: [PATCH] range-diff: don't segfault with mode-only changes
>
> If we don't have a new file, deleted file or renamed file in a diff,
> we currently add 'patch.new_name' to the range-diff header. This
> works well for files that are changed. However if we have a pure mode
> change, 'patch.new_name' is NULL, and thus range-diff segfaults.
>
> We can however rely on 'patch.def_name' in that case, which is
> extracted from the 'diff --git' line and should be equal to
> 'patch.new_name'. Use that instead to avoid the segfault.
>
> Signed-off-by: Thomas Gummerer <t.gummerer@xxxxxxxxx>
> ---
> range-diff.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/range-diff.c b/range-diff.c
> index ba1e9a4265..d8d906b3c6 100644
> --- a/range-diff.c
> +++ b/range-diff.c
> @@ -116,20 +116,20 @@ static int read_patches(const char *range, struct string_list *list)
> if (len < 0)
> die(_("could not parse git header '%.*s'"), (int)len, line);
> strbuf_addstr(&buf, " ## ");
> - if (patch.is_new > 0)
> + free(current_filename);
> + if (patch.is_new > 0) {
> strbuf_addf(&buf, "%s (new)", patch.new_name);
> - else if (patch.is_delete > 0)
> + current_filename = xstrdup(patch.new_name);
> + } else if (patch.is_delete > 0) {
> strbuf_addf(&buf, "%s (deleted)", patch.old_name);
> - else if (patch.is_rename)
> - strbuf_addf(&buf, "%s => %s", patch.old_name, patch.new_name);
> - else
> - strbuf_addstr(&buf, patch.new_name);
> -
> - free(current_filename);
> - if (patch.is_delete > 0)
> current_filename = xstrdup(patch.old_name);
> - else
> + } else if (patch.is_rename) {
> + strbuf_addf(&buf, "%s => %s", patch.old_name, patch.new_name);
> current_filename = xstrdup(patch.new_name);
> + } else {
> + strbuf_addstr(&buf, patch.def_name);
> + current_filename = xstrdup(patch.def_name);
> + }
>
> if (patch.new_mode && patch.old_mode &&
> patch.old_mode != patch.new_mode)
> --
I am not quite sure that this fixes it... Here is my regression test case:
-- snipsnap --
diff --git a/t/t3206-range-diff.sh b/t/t3206-range-diff.sh
index ec548654ce1..6aca7f5a5b1 100755
--- a/t/t3206-range-diff.sh
+++ b/t/t3206-range-diff.sh
@@ -354,4 +354,18 @@ test_expect_success 'format-patch --range-diff as commentary' '
grep "> 1: .* new message" 0001-*
'
+test_expect_success 'range-diff and mode-only changes' '
+ git switch -c mode-only &&
+
+ test_commit mode-only &&
+
+ : pretend it is executable &&
+ git add --chmod=+x mode-only.t &&
+ chmod a+x mode-only.t &&
+ test_tick &&
+ git commit -m mode-only &&
+
+ git range-diff @^...
+'
+
test_done
