Re: [PATCHv10 4/4] status: better advices when splitting a commit (during rebase -i)

[Junio C Hamano <gitster@pobox.com>]

Lucien Kong <Lucien.Kong@ensimag.imag.fr> writes:

> Add new informative help messages at the output of 'git status' when
> the user is splitting a commit. The code figures this state by
> comparing the contents of the following files in the .git/ directory:
> 	  - HEAD
> 	  - ORIG_HEAD
> 	  - rebase-merge/amend
> 	  - rebase-merge/orig-head

It may be just me but I would find it easier to read if you had a
blank line before this four-item enumerated list.

> diff --git a/wt-status.c b/wt-status.c
> index fcde045..5496a1f 100644
> --- a/wt-status.c
> +++ b/wt-status.c
> @@ -12,6 +12,7 @@
>  #include "refs.h"
>  #include "submodule.h"
>  #include "column.h"
> +#include "strbuf.h"
>  
>  static char default_wt_status_colors[][COLOR_MAXLEN] = {
>  	GIT_COLOR_NORMAL, /* WT_STATUS_HEADER */
> @@ -817,6 +818,51 @@ static void show_am_in_progress(struct wt_status *s,
>  	wt_status_print_trailer(s);
>  }
>  
> +static char *read_line_from_git_path(const char *filename)
> +{
> +	struct strbuf buf = STRBUF_INIT;
> +	FILE *fp = fopen(git_path("%s", filename), "r");
> +	if (!fp) {
> +		strbuf_release(&buf);
> +		return NULL;
> +	}
> +	strbuf_getline(&buf, fp, '\n');
> +	if (!fclose(fp)) {
> +		return strbuf_detach(&buf, NULL);
> +	} else {
> +		strbuf_release(&buf);
> +		return NULL;
> +	}
> +}

With this code, read_line_from_git_path("HEAD") will read:

	[0-9a-f]{40} when the HEAD is detached;

        ref: refs/heads/<current-branch-name> when textual symref is
        in use (and you are on the branch); or

	[0-9a-f]{40} stored in refs/heads/<current-branch-name> when
	symlink symref is in use (and you are on the branch).

> +static int split_commit_in_progress(struct wt_status *s)
> +{
> +	int split_in_progress = 0;
> +	char *head = read_line_from_git_path("HEAD");
> +	char *orig_head = read_line_from_git_path("ORIG_HEAD");
> +	char *rebase_amend = read_line_from_git_path("rebase-merge/amend");
> +	char *rebase_orig_head = read_line_from_git_path("rebase-merge/orig-head");
> +
> +	if (!head || !orig_head || !rebase_amend || !rebase_orig_head || !prefixcmp(head, "ref: "))
> +		return split_in_progress;

I think the above

	!prefixcmp(head, "ref: ")

is probably a mistake; shouldn't it be

	strcmp(s->branch, "HEAD")

which is used in wt_status_print() to diagnose that you are on a
detached HEAD (which is the normal case)?  Otherwise head may point
at the commit object name read from "refs/heads/current" through a
symbolic link .git/HEAD that points at "refs/heads/current".