Junio C Hamano <gitster@xxxxxxxxx> writes:
> ... then we may have had split (3) into three pieces:
>
> (3a) material before the pure diff (e.g. diffstat, etc.)
> (3b) pure diff
> (3c) trailing junk (e.g. base-commit info, e-mail signature, etc.)
> ...
> So, because there is no such need so far, there is no tool in the
> Git toolbox to split (3) into three pieces.
>
> You're welcome to write one, but the current toolset does not need
> it.
Writing something that reads (3), discarding lines before the first
"diff --git", counting lines that appear on "@@ ... @@" line while
copying it to the output, repeating the process when you see
something other than "diff --git" (i.e. beginning of the patch for
the next path) or "@@ ... @@" (i.e. another hunk in the patch for
the current path), and discarding the rest may be trivial.
But in practice, people edit their diff [*1*], forgetting the line
counts on the "@@ ... @@" lines, and it helps the maintainer to have
the whole (3), not only (3b), in a single file to recover from such
a broken patch submission.
So adding another tool to produce (3b) only is fine, but an attempt
to get rid of (3) and to claim that (3b) replaces the need for (3)
is highly discouraged.
Thanks.
[Footnote]
*1* Even when people edit without changing the line numbers (imagine
a typofix on a '+' line), I saw that "patch" mode of Emacs broke
the line count on "@@ ...@@" line of the last hunk when the
patch ends with certain patterns.
