Re: [PATCH 3/4] submodule.c: harden submodule_move_head against broken submodules

["Philip Oakley" <philipoakley@iee.org>]

From: "Stefan Beller" <sbeller@google.com>
> Early on in submodule_move_head just after the check if the submodule is
> initialized, we need to check if the submodule is populated correctly.
>
> If the submodule is initialized but doesn't look like populated, this
s/like//   or     s/like/like it is/

> is a red flag and can indicate multiple sorts of failures:
> (1) The submodule may be recorded at an object name, that is missing.
> (2) The submodule '.git' file link may be broken and it is not pointing
>    at a repository.
>
> In both cases we want to complain to the user in the non-forced mode,
> and in the forced mode ignoring the old state and just moving the
> submodule into its new state with a fixed '.git' file link.
>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---
--
Philip

> submodule.c               | 17 +++++++++++++++++
> t/lib-submodule-update.sh | 23 ++++++++++++++++++++---
> 2 files changed, 37 insertions(+), 3 deletions(-)
>
> diff --git a/submodule.c b/submodule.c
> index 2fa42519a4..dda1ead854 100644
> --- a/submodule.c
> +++ b/submodule.c
> @@ -1331,10 +1331,19 @@ int submodule_move_head(const char *path,
>  int ret = 0;
>  struct child_process cp = CHILD_PROCESS_INIT;
>  const struct submodule *sub;
> + int *errorcode, error_code;
>
>  if (!is_submodule_initialized(path))
>  return 0;
>
> + if (flags & SUBMODULE_MOVE_HEAD_FORCE)
> + errorcode = &error_code;
> + else
> + errorcode = NULL;
> +
> + if (old && !is_submodule_populated_gently(path, errorcode))
> + return 0;
> +
>  sub = submodule_from_path(null_sha1, path);
>
>  if (!sub)
> @@ -1361,6 +1370,14 @@ int submodule_move_head(const char *path,
>  /* make sure the index is clean as well */
>  submodule_reset_index(path);
>  }
> +
> + if (old && (flags & SUBMODULE_MOVE_HEAD_FORCE)) {
> + struct strbuf sb = STRBUF_INIT;
> + strbuf_addf(&sb, "%s/modules/%s",
> +     get_git_common_dir(), sub->name);
> + connect_work_tree_and_git_dir(path, sb.buf);
> + strbuf_release(&sb);
> + }
>  }
>
>  prepare_submodule_repo_env_no_git_dir(&cp.env_array);
> diff --git a/t/lib-submodule-update.sh b/t/lib-submodule-update.sh
> index 22dd9e060c..f0b1b18206 100755
> --- a/t/lib-submodule-update.sh
> +++ b/t/lib-submodule-update.sh
> @@ -1213,14 +1213,31 @@ test_submodule_forced_switch_recursing () {
>  )
>  '
>  # Updating a submodule from an invalid sha1 updates
> - test_expect_success "$command: modified submodule does not update 
> submodule work tree from invalid commit" '
> + test_expect_success "$command: modified submodule does update submodule 
> work tree from invalid commit" '
>  prolog &&
>  reset_work_tree_to_interested invalid_sub1 &&
>  (
>  cd submodule_update &&
>  git branch -t valid_sub1 origin/valid_sub1 &&
> - test_must_fail $command valid_sub1 &&
> - test_superproject_content origin/invalid_sub1
> + $command valid_sub1 &&
> + test_superproject_content origin/valid_sub1 &&
> + test_submodule_content sub1 origin/valid_sub1
> + )
> + '
> +
> + # Old versions of Git were buggy writing the .git link file
> + # (e.g. before f8eaa0ba98b and then moving the superproject repo
> + # whose submodules contained absolute paths)
> + test_expect_success "$command: updating submodules fixes .git links" '
> + prolog &&
> + reset_work_tree_to_interested add_sub1 &&
> + (
> + cd submodule_update &&
> + git branch -t modify_sub1 origin/modify_sub1 &&
> + echo "gitdir: bogus/path" >sub1/.git &&
> + $command modify_sub1 &&
> + test_superproject_content origin/modify_sub1 &&
> + test_submodule_content sub1 origin/modify_sub1
>  )
>  '
> }
> -- 
> 2.12.2.603.g7b28dc31ba
>
>