Re: [PATCH 2/4] push, fetch: error out for submodule entries not pointing to commits

> From: Stefan Beller <sbeller@google.com>
> 
> The check_has_commit helper uses resolves a submodule entry to a
> commit, when validating its existence. As a side effect this means
> tolerates a submodule entry pointing to a tag, which is not a valid
> submodule entry that git commands would know how to cope with.
> 
> Tighten the check to require an actual commit, not a tag pointing to a
> commit.
> 
> Also improve the error handling when a submodule entry points to
> non-commit (e.g., a blob) to error out instead of warning and
> pretending the pointed to object doesn't exist.
> 
> Signed-off-by: Stefan Beller <sbeller@google.com>
> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>

> ---
>  submodule.c                    | 33 +++++++++++++++++++++++++--------
>  t/t5531-deep-submodule-push.sh | 10 ++++++++++
>  2 files changed, 35 insertions(+), 8 deletions(-)
> 
> diff --git a/submodule.c b/submodule.c
> index 3cea8221e0..e0da55920d 100644
> --- a/submodule.c
> +++ b/submodule.c
> @@ -767,19 +767,36 @@ static int append_oid_to_argv(const struct object_id *oid, void *data)
>  	return 0;
>  }
>  
> +struct has_commit_data {
> +	int result;
> +	const char *path;
> +};
> +
>  static int check_has_commit(const struct object_id *oid, void *data)
>  {
> -	int *has_commit = data;
> +	struct has_commit_data *cb = data;
>  
> -	if (!lookup_commit_reference(oid))
> -		*has_commit = 0;
> +	enum object_type type = sha1_object_info(oid->hash, NULL);
>  
> -	return 0;
> +	switch (type) {
> +	case OBJ_COMMIT:
> +		return 0;
> +	case OBJ_BAD:
> +		/*
> +		 * Object is missing or invalid. If invalid, an error message
> +		 * has already been printed.
> +		 */
> +		cb->result = 0;
> +		return 0;
> +	default:
> +		die(_("submodule entry '%s' (%s) is a %s, not a commit"),
> +		    cb->path, oid_to_hex(oid), typename(type));
> +	}
>  }
>  
>  static int submodule_has_commits(const char *path, struct oid_array *commits)
>  {
> -	int has_commit = 1;
> +	struct has_commit_data has_commit = { 1, path };
>  
>  	/*
>  	 * Perform a cheap, but incorrect check for the existence of 'commits'.
> @@ -795,7 +812,7 @@ static int submodule_has_commits(const char *path, struct oid_array *commits)
>  
>  	oid_array_for_each_unique(commits, check_has_commit, &has_commit);
>  
> -	if (has_commit) {
> +	if (has_commit.result) {
>  		/*
>  		 * Even if the submodule is checked out and the commit is
>  		 * present, make sure it exists in the submodule's object store
> @@ -814,12 +831,12 @@ static int submodule_has_commits(const char *path, struct oid_array *commits)
>  		cp.dir = path;
>  
>  		if (capture_command(&cp, &out, GIT_MAX_HEXSZ + 1) || out.len)
> -			has_commit = 0;
> +			has_commit.result = 0;
>  
>  		strbuf_release(&out);
>  	}
>  
> -	return has_commit;
> +	return has_commit.result;
>  }
>  
>  static int submodule_needs_pushing(const char *path, struct oid_array *commits)
> diff --git a/t/t5531-deep-submodule-push.sh b/t/t5531-deep-submodule-push.sh
> index 0f84a53146..39cb2c1c34 100755
> --- a/t/t5531-deep-submodule-push.sh
> +++ b/t/t5531-deep-submodule-push.sh
> @@ -298,6 +298,16 @@ test_expect_success 'push succeeds if submodule commit disabling recursion from
>  	)
>  '
>  
> +test_expect_success 'submodule entry pointing at a tag is error' '
> +	git -C work/gar/bage tag -a test1 -m "tag" &&
> +	tag=$(git -C work/gar/bage rev-parse test1^{tag}) &&
> +	git -C work update-index --cacheinfo 160000 "$tag" gar/bage &&
> +	git -C work commit -m "bad commit" &&
> +	test_when_finished "git -C work reset --hard HEAD^" &&
> +	test_must_fail git -C work push --recurse-submodules=on-demand ../pub.git master 2>err &&
> +	test_i18ngrep "is a tag, not a commit" err
> +'
> +
>  test_expect_success 'push fails if recurse submodules option passed as yes' '
>  	(
>  		cd work/gar/bage &&
> -- 
> 2.14.1.690.gbb1197296e
>