Subject: Re: [PATCH v3 2/2] revision: un-regress --exclude-promisor-objects

From: Emily Shaffer <[email-masked]>
Date: Wed, 25 Mar 2020 13:50:35 -0700

On Sat, Jan 11, 2020 at 02:34:56PM -0800, Jonathan Tan wrote:
> Before commit 4cf67869b2 ("list-objects.c: don't segfault for missing
> cmdline objects", 2018-12-06),
> 
>   git rev-list --exclude-promisor-objects $A_MISSING_PROMISOR_OBJECT
> 
> succeeds. But after that commit, this invocation produces a non-zero
> result.
> 
> Restore this functionality: since get_reference() already does what we
> need, we can just use its return value; skip the arg if the return value
> is NULL, and use it otherwise (if the arg is invalid, get_reference()
> already dies). With this commit, --exclude-promisor-objects treats both
> promisor objects passed through the CLI and promisor objects found
> through traversal in the same say: it excludes them, so it does not
> matter whether they're missing or not.

Since the return code is changing I'm kind of worried about what other
impacts this will have. What's the call tree for handle_revision_arg
look like?

It looks like it's called in a couple places by revision.c and by
builtin/pack-objects.c, but because of the way args are packed up in
struct rev_info, it's hard to tell when those callers will be affected
or not.

> ---
>  revision.c               |  2 +-
>  t/t0410-partial-clone.sh | 12 +++---------
>  2 files changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/revision.c b/revision.c
> index 91ca194388..0659a09b02 100644
> --- a/revision.c
> +++ b/revision.c
> @@ -1917,7 +1917,7 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
>  		verify_non_filename(revs->prefix, arg);
>  	object = get_reference(revs, arg, &oid, flags ^ local_flags);
>  	if (!object)
> -		return revs->ignore_missing ? 0 : -1;
> +		return 0;
>  	add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
>  	add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);
>  	free(oc.path);
> diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
> index a3988bd4b8..b251985e82 100755
> --- a/t/t0410-partial-clone.sh
> +++ b/t/t0410-partial-clone.sh
> @@ -397,7 +397,7 @@ test_expect_success 'rev-list stops traversal at promisor commit, tree, and blob
>  	grep $(git -C repo rev-parse bar) out  # sanity check that some walking was done
>  '
>  
> -test_expect_success 'rev-list dies for missing objects on cmd line' '
> +test_expect_success 'rev-list accepts missing and promised objects on command line ' '
>  	rm -rf repo &&
>  	test_create_repo repo &&
>  	test_commit -C repo foo &&
> @@ -416,15 +416,9 @@ test_expect_success 'rev-list dies for missing objects on cmd line' '
>  	git -C repo config extensions.partialclone "arbitrary string" &&
>  
>  	for OBJ in "$COMMIT" "$TREE" "$BLOB"; do
> -		test_must_fail git -C repo rev-list --objects \
> +		git -C repo rev-list --objects \
>  			--exclude-promisor-objects "$OBJ" &&
> -		test_must_fail git -C repo rev-list --objects-edge-aggressive \
> -			--exclude-promisor-objects "$OBJ" &&
> -
> -		# Do not die or crash when --ignore-missing is passed.
> -		git -C repo rev-list --ignore-missing --objects \
> -			--exclude-promisor-objects "$OBJ" &&
> -		git -C repo rev-list --ignore-missing --objects-edge-aggressive \
> +		git -C repo rev-list --objects-edge-aggressive \
>  			--exclude-promisor-objects "$OBJ"

It seems to me the -ignore-missing tests should still pass and therefore
shouldn't be removed, no? But then I looked a little harder, and it
looks like before the test said, "This call fails, but with
--ignore-missing it does not fail" - and now the test just says "This
call does not fail". So it looks OK to me.

>  	done
>  '
> -- 
> 2.25.0.rc1.283.g88dfdc4193-goog
>