Re: [RFC PATCH 8/8] read-tree: add "--super-prefix" option, eliminate global

[Glen Choo <chooglen@google.com>]

Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:

> That "submodule_move_head()" function was then only invoked by
> "read-tree" itself, but now rather than setting an environment
> variable to pass "--super-prefix" between cmd_read_tree() we:
>
> - Set a new "super_prefix" in "struct unpack_trees_options". The
>   "super_prefixed()" function in "unpack-trees.c" added in [5] will now
>   use this, rather than get_super_prefix() looking up the environment
>   variable we set earlier in the same process.
>
> - Add the same field to the "struct checkout", which is only needed to
>   ferry the "super_prefix" in the "struct unpack_trees_options" all the
>   way down to the "entry.c" callers of "submodule_move_head()".
>
>   Those calls which used the super prefix all originated in
>   "cmd_read_tree()". The only other caller is the "unlink_entry()"
>   caller in "builtin/checkout.c", which now passes a "NULL".
>
> 1. 74866d75793 (git: make super-prefix option, 2016-10-07)
> 2. e77aa336f11 (ls-files: optionally recurse into submodules, 2016-10-07)
> 3. 89c86265576 (submodule helper: support super prefix, 2016-12-08)
> 4. 0281e487fd9 (grep: optionally recurse into submodules, 2016-12-16)
> 5. 3d415425c7b (unpack-trees: support super-prefix option, 2017-01-17)
> 6. 188dce131fa (ls-files: use repository object, 2017-06-22)
> 7. f9ee2fcdfa0 (grep: recurse in-process using 'struct repository', 2017-08-02)
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>

[...]

> diff --git a/submodule.h b/submodule.h
> index e5ee13fb06a..36a7f7c5b32 100644
> --- a/submodule.h
> +++ b/submodule.h
> @@ -150,9 +150,8 @@ int validate_submodule_git_dir(char *git_dir, const char *submodule_name);
>  
>  #define SUBMODULE_MOVE_HEAD_DRY_RUN (1<<0)
>  #define SUBMODULE_MOVE_HEAD_FORCE   (1<<1)
> -int submodule_move_head(const char *path,
> -			const char *old,
> -			const char *new_head,
> +int submodule_move_head(const char *path, const char *super_prefix,
> +			const char *old_head, const char *new_head,
>  			unsigned flags);
>  
>  void submodule_unset_core_worktree(const struct submodule *sub);

This signature change turned out to be far less disruptive than I
expected, nice. It helps that we already had a natural home for these,
i.e. "struct checkout" and "struct unpack_trees_options".