Re: [PATCH v2] describe: refresh the index when 'broken' flag is used

> When describe is run with 'dirty' flag, we refresh the index
> to make sure it is in sync with the filesystem before
> determining if the working tree is dirty.  However, this is
> not done for the codepath where the 'broken' flag is used.
>
> This causes `git describe --broken --dirty` to false
> positively report the worktree being dirty if a file has
> different stat info than what is recorded in the index.
> Running `git update-index -q --refresh` to refresh the index
> before running diff-index fixes the problem.
>
> Also add tests to deliberately update stat info of a
> file before running describe to verify it behaves correctly.
>
> Reported-by: Paul Millar <paul.millar@desy.de>
> Suggested-by: Junio C Hamano <gitster@pobox.com>
> Helped-by: Junio C Hamano <gitster@pobox.com>
> Signed-off-by: Abhijeet Sonar <abhijeet.nkt@gmail.com>
> ---
>  builtin/describe.c  | 12 ++++++++++++
>  t/t6120-describe.sh | 32 ++++++++++++++++++++++++++++++++
>  2 files changed, 44 insertions(+)
>
> diff --git a/builtin/describe.c b/builtin/describe.c
> index e5287eddf2..3e751f1239 100644
> --- a/builtin/describe.c
> +++ b/builtin/describe.c
> @@ -53,6 +53,10 @@ static const char *diff_index_args[] = {
>  	"diff-index", "--quiet", "HEAD", "--", NULL
>  };
>
> +static const char *update_index_args[] = {
> +	"update-index", "--unmerged", "-q", "--refresh", NULL
> +};
> +
>  struct commit_name {
>  	struct hashmap_entry entry;
>  	struct object_id peeled;
> @@ -645,6 +649,14 @@ int cmd_describe(int argc, const char **argv, const char *prefix)
>  	if (argc == 0) {
>  		if (broken) {
>  			struct child_process cp = CHILD_PROCESS_INIT;
> +			struct child_process update_index_cp = CHILD_PROCESS_INIT;
> +
> +			strvec_pushv(&update_index_cp.args, update_index_args);
> +			update_index_cp.git_cmd = 1;
> +			update_index_cp.no_stdin = 1;
> +			update_index_cp.no_stdout = 1;
> +			run_command(&update_index_cp);
> +

>  			strvec_pushv(&cp.args, diff_index_args);
>  			cp.git_cmd = 1;
>  			cp.no_stdin = 1;
> diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh
> index e78315d23d..ac781a7b52 100755
> --- a/t/t6120-describe.sh
> +++ b/t/t6120-describe.sh
> @@ -671,4 +671,36 @@ test_expect_success 'setup misleading taggerdates' '
>
>  check_describe newer-tag-older-commit~1 --contains unique-file~2
>
> +test_expect_success 'describe --dirty with a file with changed stat' '

> +	git init stat-dirty &&
> +	cd stat-dirty &&
> +
> +	echo A >file &&
> +	git add file &&
> +	git commit -m A &&
> +	git tag A -a -m A &&
> +
> +	cat file >file.new &&
> +	mv file.new file &&
> +	git describe --dirty >actual &&
> +	echo "A" >expected &&
> +	test_cmp expected actual
> +'

> +test_expect_success 'describe --dirty --broken with a file with changed stat' '
> +	git init stat-dirty-broken &&
> +	cd stat-dirty-broken &&
> +
> +	echo A >file &&
> +	git add file &&
> +	git commit -m A &&
> +	git tag A -a -m A &&
> +
> +	cat file >file.new &&
> +	mv file.new file &&
> +	git describe --dirty --broken >actual &&
> +	echo "A" >expected &&
> +	test_cmp expected actual
> +'