Subject: Re: [PATCH v2 2/2] for-each-repo: work correctly in a worktree

From: Derrick Stolee <[email-masked]>
Date: Thu, 26 Feb 2026 10:29:47 -0500

On 2/25/2026 8:13 AM, Jeff King wrote:
> On Wed, Feb 25, 2026 at 06:44:51AM -0500, Derrick Stolee wrote:
> 
>>> Looking at run-command.c:prep_childenv(), it seems that you can pass
>>> "VAR=VAL" to "export VAR=VAL" in the child, and pass "VAR" to "unset
>>> VAR" in the child.

> But I really think you should consider keeping config-related variables
> in place, as prepare_other_repo_env() does. Otherwise something like:
> 
>   git -c pack.threads=1 for-each-repo repack -ad
> 
> will ignore that config in the sub-processes (whereas it currently is
> respected).
> 
> And for that, you do need to loop yourself.

Great point. Here's another attempt:

static int run_command_on_repo(const char *path, int argc, const char ** argv)
{
	int i = 0;
	struct child_process child = CHILD_PROCESS_INIT;
	char *abspath = interpolate_path(path, 0);

	while (local_repo_env[i]) {
		/*
		 * Preserve pre-builtin options:
		 * - CONFIG_ENVIRONMENT, CONFIG_DATA_ENVIRONMENT, and
		 *   CONFIG_COUNT_ENVIRONMENT persist -c <name>=<value>
		 *   and --config-env=<name>=<envvar> options.
		 * - NO_REPLACE_OBJECTS_ENVIRONMENT persists the
		 *   --no-replace-objects option.
		 *
		 * Note that the following options are not in local_repo_env:
		 * - EXEC_PATH_ENVIRONMENT persists --exec-path option.
		 */
		if (strncmp(local_repo_env[i], "CONFIG_", 7) &&
		    strcmp(local_repo_env[i], NO_REPLACE_OBJECTS_ENVIRONMENT))
			strvec_push(&child.env, local_repo_env[i]);

		i++;
	}

	child.git_cmd = 1;
	strvec_pushl(&child.args, "-C", abspath, NULL);

	for (i = 0; i < argc; i++)
		strvec_push(&child.args, argv[i]);

	free(abspath);

	return run_command(&child);
}

This comment details my findings from comparing the list in
local_repo_env[] and the top-level options listed in
Documentation/git.adoc. That's how I was able to find that
--exec-path sets an environment variable that's NOT in the
list and we want to be sure we don't set it.

Should we add the comparison to EXEC_PATH_ENVIRONMENT as a
precaution to make sure it's not added to local_repo_env in
the future? Or is that too defensive?

Thanks,
-Stolee