On Wed, Apr 12, 2023 at 12:22:31PM +0200, Patrick Steinhardt wrote:
> Fix this bug by exiting early in case we have determined that the MIDX
> wouldn't have any packfiles to index. While the request itself does not
> make much sense anyway, it is still preferable to exit gracefully than
> to abort.
Interesting. This reminded me quite a bit of eb57277ba3 (midx: prevent
writing a .bitmap without any objects, 2022-02-09) which tackled a
similar problem of trying to write a MIDX bitmap without any objects.
We may want to consider moving that conditional further up, since this
makes the conditional added in eb57277ba3 dead code AFAICT. Here's a
patch on top of this one that I think would do the trick.
It has the added benefit of sticking a:
warning: unknown preferred pack: 'does-not-exist'
in the output before dying, which might be nice (though I doubt anybody
will ever see it ;-)). The main difference is that we unset the bitmap
related bits from `flags`, which avoids us trying to compute a preferred
pack in the first place.
For it to work, though, we need to make sure that ctx.preferred_pack_idx
is set to -1, and not zero-initialized, since we'll segfault otherwise
when trying to read into an empty array.
--- 8< ---
diff --git a/midx.c b/midx.c
index 22ea7ffb75..dc4821eab8 100644
--- a/midx.c
+++ b/midx.c
@@ -1263,6 +1263,7 @@ static int write_midx_internal(const char *object_dir,
ctx.nr = 0;
ctx.alloc = ctx.m ? ctx.m->num_packs : 16;
ctx.info = NULL;
+ ctx.preferred_pack_idx = -1;
ALLOC_ARRAY(ctx.info, ctx.alloc);
if (ctx.m) {
@@ -1307,10 +1308,10 @@ static int write_midx_internal(const char *object_dir,
for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &ctx);
stop_progress(&ctx.progress);
- if (!ctx.nr) {
- error(_("no pack files to index."));
- result = 1;
- goto cleanup;
+ if (!ctx.entries_nr) {
+ if (flags & MIDX_WRITE_BITMAP)
+ warning(_("refusing to write multi-pack .bitmap without any objects"));
+ flags &= ~(MIDX_WRITE_REV_INDEX | MIDX_WRITE_BITMAP);
}
if ((ctx.m && ctx.nr == ctx.m->num_packs) &&
@@ -1488,12 +1489,6 @@ static int write_midx_internal(const char *object_dir,
goto cleanup;
}
- if (!ctx.entries_nr) {
- if (flags & MIDX_WRITE_BITMAP)
- warning(_("refusing to write multi-pack .bitmap without any objects"));
- flags &= ~(MIDX_WRITE_REV_INDEX | MIDX_WRITE_BITMAP);
- }
-
cf = init_chunkfile(f);
add_chunk(cf, MIDX_CHUNKID_PACKNAMES, pack_name_concat_len,
diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
index be7f3c1e1f..8a17361272 100755
--- a/t/t5319-multi-pack-index.sh
+++ b/t/t5319-multi-pack-index.sh
@@ -188,10 +188,9 @@ test_expect_success 'write with no objects and preferred pack' '
git init empty &&
test_must_fail git -C empty multi-pack-index write \
--stdin-packs --preferred-pack=does-not-exist </dev/null 2>err &&
- cat >expect <<-EOF &&
- error: no pack files to index.
- EOF
- test_cmp expect err
+ cat err &&
+ grep "warning: unknown preferred pack: .does-not-exist." err &&
+ grep "error: no pack files to index." err
'
test_expect_success 'write progress off for redirected stderr' '
--- >8 ---
Thanks,
Taylor
