Re: git treeless-clone + wait + pull → problem, again pull → OK

From

Jeff King <peff@peff.net>

Date

Jul 22, 2025, 09:24 UTC

Message-ID

<20250722092403.GA889790@coredump.intra.peff.net>

In-Reply-To

<20250722091749.GA864077@coredump.intra.peff.net>

On Tue, Jul 22, 2025 at 05:17:49AM -0400, Jeff King wrote:

> Whether or not fetch should avoid kicking off that big string of
> fetches, I don't know. Passing --no-recurse-submodules obviously dulls
> the pain. Perhaps the default behavior ought to be different in a
> tree-less repo. Or maybe those tree diffs should be done with
> lazy-fetching turned off (there is no point in recursing for a version
> of a submodule whose parent tree we don't even have!). But I think
> that's all orthogonal to the race.

diff --git a/submodule.c b/submodule.c
index f8373a9ea7..e064fefd9a 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1851,7 +1851,12 @@ int fetch_submodules(struct repository *r,
 	strvec_push(&spf.args, "--recurse-submodules-default");
 	/* default value, "--submodule-prefix" and its value are added later */
 
-	calculate_changed_submodule_paths(r, &spf.changed_submodule_names);
+	{
+		int save = fetch_if_missing;
+		fetch_if_missing = 0;
+		calculate_changed_submodule_paths(r, &spf.changed_submodule_names);
+		fetch_if_missing = save;
+	}
 	string_list_sort(&spf.changed_submodule_names);
 	run_processes_parallel(&opts);
 

But it doesn't work, because all of the diff code under the hood in the
calculate_changed_submodule_paths() call is not prepared for trees to be
missing. So you just get:

  fatal: unable to read tree (3a112b53a40e2d1240b2a4d01d5e616e0f4f09fd)

or similar. We'd need to teach the diff code some permissive mode where
it quietly ignores trees we don't have locally.

-Peff