Re: [PATCH] log: decorate detached HEAD differently

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

Michael J Gruber <git@drmicha.warpmail.net> writes:

> "git status" and "git branch" let the user know when the HEAD is
> detached, as well as the current branch, while "git log --decorate" does not.
>
> Change the decoration by a non-detached HEAD pointing to branch foo to
> "HEAD->foo". This can be seen as giving more information about the
> decoration item itself in the same way as we prefix tags by "tag: ".
>
> Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
> ---
>
> Notes:
>     v2 decorates the HEAD pointing to master as "HEAD->master", a detached
>     HEAD just as "HEAD". The "->" hopefully conveys the symlink nature - a
>     "=" would be confusing.
>     
>     Somehow I still prefer "detached HEAD", dunno. Maybe in addition?
>     
>     Note that now a checked branch is listed twice, once as target of the
>     HEAD, once as branch: They are two different refs and colored differently.

The pointee of HEAD would always be branch and will always appear on
the output when you show HEAD->$name_of_that_branch; is it feasible
to drop the duplicate, I wonder?

>
>  log-tree.c                             | 8 +++++++-
>  t/t4013/diff.log_--decorate=full_--all | 2 +-
>  t/t4013/diff.log_--decorate_--all      | 2 +-
>  t/t4207-log-decoration-colors.sh       | 2 +-
>  4 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/log-tree.c b/log-tree.c
> index 7f0890e..38862bb 100644
> --- a/log-tree.c
> +++ b/log-tree.c
> @@ -118,8 +118,11 @@ static int add_ref_decoration(const char *refname, const unsigned char *sha1, in
>  		type = DECORATION_REF_TAG;
>  	else if (!strcmp(refname, "refs/stash"))
>  		type = DECORATION_REF_STASH;
> -	else if (!strcmp(refname, "HEAD"))
> +	else if (!strcmp(refname, "HEAD")) {
> +		unsigned char junk_sha1[20];
>  		type = DECORATION_REF_HEAD;
> +		refname = resolve_ref_unsafe("HEAD", 0, junk_sha1, NULL);
> +	}
>  
>  	if (!cb_data || *(int *)cb_data == DECORATE_SHORT_REFS)
>  		refname = prettify_refname(refname);
> @@ -198,6 +201,9 @@ void format_decorations_extended(struct strbuf *sb,
>  		strbuf_addstr(sb, decorate_get_color(use_color, decoration->type));
>  		if (decoration->type == DECORATION_REF_TAG)
>  			strbuf_addstr(sb, "tag: ");
> +		else if (decoration->type == DECORATION_REF_HEAD &&
> +			 strcmp(decoration->name, "HEAD"))
> +			strbuf_addstr(sb, "HEAD->");
>  		strbuf_addstr(sb, decoration->name);
>  		strbuf_addstr(sb, color_reset);
>  		prefix = separator;
> diff --git a/t/t4013/diff.log_--decorate=full_--all b/t/t4013/diff.log_--decorate=full_--all
> index 44d4525..3758ae9 100644
> --- a/t/t4013/diff.log_--decorate=full_--all
> +++ b/t/t4013/diff.log_--decorate=full_--all
> @@ -5,7 +5,7 @@ Date:   Mon Jun 26 00:06:00 2006 +0000
>  
>      Rearranged lines in dir/sub
>  
> -commit 59d314ad6f356dd08601a4cd5e530381da3e3c64 (HEAD, refs/heads/master)
> +commit 59d314ad6f356dd08601a4cd5e530381da3e3c64 (HEAD->refs/heads/master, refs/heads/master)
>  Merge: 9a6d494 c7a2ab9
>  Author: A U Thor <author@example.com>
>  Date:   Mon Jun 26 00:04:00 2006 +0000
> diff --git a/t/t4013/diff.log_--decorate_--all b/t/t4013/diff.log_--decorate_--all
> index 27d3eab..df702ae 100644
> --- a/t/t4013/diff.log_--decorate_--all
> +++ b/t/t4013/diff.log_--decorate_--all
> @@ -5,7 +5,7 @@ Date:   Mon Jun 26 00:06:00 2006 +0000
>  
>      Rearranged lines in dir/sub
>  
> -commit 59d314ad6f356dd08601a4cd5e530381da3e3c64 (HEAD, master)
> +commit 59d314ad6f356dd08601a4cd5e530381da3e3c64 (HEAD->master, master)
>  Merge: 9a6d494 c7a2ab9
>  Author: A U Thor <author@example.com>
>  Date:   Mon Jun 26 00:04:00 2006 +0000
> diff --git a/t/t4207-log-decoration-colors.sh b/t/t4207-log-decoration-colors.sh
> index 925f577..0437ff2 100755
> --- a/t/t4207-log-decoration-colors.sh
> +++ b/t/t4207-log-decoration-colors.sh
> @@ -44,7 +44,7 @@ test_expect_success setup '
>  '
>  
>  cat >expected <<EOF
> -${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_HEAD}HEAD${c_reset}${c_commit},\
> +${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_HEAD}HEAD->master${c_reset}${c_commit},\
>   ${c_tag}tag: v1.0${c_reset}${c_commit},\
>   ${c_tag}tag: B${c_reset}${c_commit},\
>   ${c_branch}master${c_reset}${c_commit})${c_reset} B