Re: [PATCH v3 4/4] stash: honor stash.index in apply, pop modes

> With stash.index=true, git-stash(1) command now tries to reinstate the
> index by default in the "apply" and "pop" modes. Not doing so creates a
> common trap [1], [2]: "git stash apply" is not the reverse of "git stash
> push" because carefully staged indices are lost and have to be manually
> recreated. OTOH, this mode is not always desirable and may create more
> conflicts when applying stashes. As usual, "--no-index" will disable
> this behavior if you set "stash.index".

> [1]: https://lore.kernel.org/git/CAPx1GvcxyDDQmCssMjEnt6JoV6qPc5ZUpgPLX3mpUC_4PNYA1w@mail.gmail.com/
> [2]: https://lore.kernel.org/git/c5a811ac-8cd3-c389-ac6d-29020a648c87@gmail.com/
> 
> Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com>
> ---
>   Documentation/config/stash.adoc |  5 +++++
>   builtin/stash.c                 |  9 ++++++--
>   t/t3903-stash.sh                | 37 +++++++++++++++++++++++++++++++++
>   3 files changed, 49 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/config/stash.adoc b/Documentation/config/stash.adoc
> index ec1edaeba6..e556105a15 100644
> --- a/Documentation/config/stash.adoc
> +++ b/Documentation/config/stash.adoc
> @@ -1,3 +1,8 @@
> +stash.index::
> +	If this is set to true, `git stash apply` and `git stash pop` will
> +	behave as if `--index` was supplied. Defaults to false. See the
> +	descriptions in linkgit:git-stash[1].
> +
>   stash.showIncludeUntracked::
>   	If this is set to true, the `git stash show` command will show
>   	the untracked files of a stash entry.  Defaults to false. See
> diff --git a/builtin/stash.c b/builtin/stash.c
> index d9b478d1d1..8a0eef3c70 100644
> --- a/builtin/stash.c
> +++ b/builtin/stash.c
> @@ -130,6 +130,7 @@ static struct strbuf stash_index_path = STRBUF_INIT;
>   static int show_stat = 1;
>   static int show_patch;
>   static int show_include_untracked;
> +static int use_index;
>   
>   /*
>    * w_commit is set to the commit containing the working tree
> @@ -662,7 +663,7 @@ static int apply_stash(int argc, const char **argv, const char *prefix,
>   {
>   	int ret = -1;
>   	int quiet = 0;
> -	int index = 0;
> +	int index = use_index;
>   	struct stash_info info = STASH_INFO_INIT;
>   	struct option options[] = {
>   		OPT__QUIET(&quiet, N_("be quiet, only report errors")),
> @@ -759,7 +760,7 @@ static int pop_stash(int argc, const char **argv, const char *prefix,
>   		     struct repository *repo UNUSED)
>   {
>   	int ret = -1;
> -	int index = 0;
> +	int index = use_index;
>   	int quiet = 0;
>   	struct stash_info info = STASH_INFO_INIT;
>   	struct option options[] = {
> @@ -864,6 +865,10 @@ static int git_stash_config(const char *var, const char *value,
>   		show_include_untracked = git_config_bool(var, value);
>   		return 0;
>   	}
> +	if (!strcmp(var, "stash.index")) {
> +		use_index = git_config_bool(var, value);
> +		return 0;
> +	}
>   	return git_diff_basic_config(var, value, ctx, cb);
>   }
>   
> diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
> index b8936a653b..d6127173b1 100755
> --- a/t/t3903-stash.sh
> +++ b/t/t3903-stash.sh
> @@ -1595,4 +1595,41 @@ setup_stash()
>   	)
>   '
>   
> +test_expect_success 'stash.index=true implies --index' '
> +	# setup for a few related tests
> +	test_commit file base &&
> +	echo index >file &&
> +	git add file &&
> +	echo working >file &&
> +	git stash &&
> +
> +	test_when_finished "git reset --hard" &&
> +	git -c stash.index=true stash apply &&
> +	echo index >expect &&
> +	git show :0:file >actual &&
> +	test_cmp expect actual &&
> +	echo working >expect &&
> +	test_cmp expect file
> +'
> +
> +test_expect_success 'stash.index=true overridden by --no-index' '
> +	test_when_finished "git reset --hard" &&
> +	git -c stash.index=true stash apply --no-index &&
> +	echo base >expect &&
> +	git show :0:file >actual &&
> +	test_cmp expect actual &&
> +	echo working >expect &&
> +	test_cmp expect file
> +'
> +
> +test_expect_success 'stash.index=false overridden by --index' '
> +	test_when_finished "git reset --hard" &&
> +	git -c stash.index=false stash apply --index &&
> +	echo index >expect &&
> +	git show :0:file >actual &&
> +	test_cmp expect actual &&
> +	echo working >expect &&
> +	test_cmp expect file
> +'
> +
>   test_done