From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 12 Jul 2021 20:52:19 GMT
Subject: Re: [PATCH] git-diff: fix missing --merge-base docs
Message-ID: <xmqqlf6b2r24.fsf@gitster.g>
In-Reply-To: <f0e7ef2433e2836fed579f2765654c5f97d5d778.1625909286.git.liu.denton@gmail.com>

Denton Liu <liu.denton@gmail.com> writes:

> When `git diff --merge-base` was introduced, the documentation included
> a few errors.
>
> In the example given for `git diff --cached --merge-base`, the
> `--cached` flag was omitted for the `--merge-base` example. Add the
> missing flag.
>
> In the `git diff <commit>` case, we failed to mention that
> `--merge-base` is an available option. Give the usage of `--merge-base`
> as an option there.
>
> Finally, there are two errors in the usage of `git diff`. Firstly, we do
> not mention `--merge-base` in the `git diff --cached` case. Mention it
> so that it's consistent with the documentation. Secondly, we put the
> `[--merge-base]` in between `<commit>` and `[<commit>...]`. Move the
> `[--merge-base]` so that it's beside `[<options>]` which is a more
> logical grouping.
>
> Signed-off-by: Denton Liu <liu.denton@gmail.com>
> ---
>  Documentation/git-diff.txt | 10 +++++++---
>  builtin/diff.c             |  4 ++--
>  2 files changed, 9 insertions(+), 5 deletions(-)

Thanks.  Both hunks look sensible.

>
> diff --git a/Documentation/git-diff.txt b/Documentation/git-diff.txt
> index 7f4c8a8ce7..6236c75c9b 100644
> --- a/Documentation/git-diff.txt
> +++ b/Documentation/git-diff.txt
> @@ -51,16 +51,20 @@ files on disk.
>  	--staged is a synonym of --cached.
>  +
>  If --merge-base is given, instead of using <commit>, use the merge base
> -of <commit> and HEAD.  `git diff --merge-base A` is equivalent to
> -`git diff $(git merge-base A HEAD)`.
> +of <commit> and HEAD.  `git diff --cached --merge-base A` is equivalent to
> +`git diff --cached $(git merge-base A HEAD)`.
>  
> -'git diff' [<options>] <commit> [--] [<path>...]::
> +'git diff' [<options>] [--merge-base] <commit> [--] [<path>...]::
>  
>  	This form is to view the changes you have in your
>  	working tree relative to the named <commit>.  You can
>  	use HEAD to compare it with the latest commit, or a
>  	branch name to compare with the tip of a different
>  	branch.
> ++
> +If --merge-base is given, instead of using <commit>, use the merge base
> +of <commit> and HEAD.  `git diff --merge-base A` is equivalent to
> +`git diff $(git merge-base A HEAD)`.
>  
>  'git diff' [<options>] [--merge-base] <commit> <commit> [--] [<path>...]::
>  
> diff --git a/builtin/diff.c b/builtin/diff.c
> index 2d87c37a17..dd8ce688ba 100644
> --- a/builtin/diff.c
> +++ b/builtin/diff.c
> @@ -26,8 +26,8 @@
>  
>  static const char builtin_diff_usage[] =
>  "git diff [<options>] [<commit>] [--] [<path>...]\n"
> -"   or: git diff [<options>] --cached [<commit>] [--] [<path>...]\n"
> -"   or: git diff [<options>] <commit> [--merge-base] [<commit>...] <commit> [--] [<path>...]\n"
> +"   or: git diff [<options>] --cached [--merge-base] [<commit>] [--] [<path>...]\n"
> +"   or: git diff [<options>] [--merge-base] <commit> [<commit>...] <commit> [--] [<path>...]\n"
>  "   or: git diff [<options>] <commit>...<commit>] [--] [<path>...]\n"
>  "   or: git diff [<options>] <blob> <blob>]\n"
>  "   or: git diff [<options>] --no-index [--] <path> <path>]\n"