Re: [RFC PATCH 0/5] format-patch: automate cover letter range-diff

[Eric Sunshine <sunshine@sunshineco.com>]

On Wed, Jun 6, 2018 at 3:16 PM, Duy Nguyen <pclouds@gmail.com> wrote:
> On Wed, May 30, 2018 at 10:03 AM, Eric Sunshine <sunshine@sunshineco.com> wrote:
>> Dscho recently implemented a 'tbdiff' replacement as a Git builtin named
>> git-branch-diff[1] which computes differences between two versions of a
>> patch series. Such a diff can be a useful aid for reviewers when
>> inserted into a cover letter. However, doing so requires manual
>> generation (invoking git-branch-diff) and copy/pasting the result into
>> the cover letter.
>
> Another option which I wanted to go is delegate part of cover letter
> generation to a hook (or just a config key that contains a shell
> command). This way it's easier to customize cover letters. We could
> still have a good fallback that does shortlog, diffstat and tbdiff.

It is common on this mailing list to turn down requests for new hooks
when the requested functionality could just as easily be implemented
via a wrapper script. So, my knee-jerk reaction is that a hook to
customize the cover letter may be overkill when the same functionality
could likely be implemented relatively easily by a shell script which
invokes git-format-patch and customizes the cover letter
after-the-fact. Same argument regarding a config key holding a shell
command. But, perhaps there are cases which don't occur to me which
could be helped by a config variable or such.

Of course, by the same reasoning, the --range-diff functionality
implemented by this patch series, which is just a convenience, could
be handled by a wrapper script, thus is not strictly needed. On the
other hand, given that interdiffs and range-diffs are so regularly
used in re-rolls on this list (and perhaps other mailing list-based
projects) may be argument enough in favor of having such an option
built into git-format-patch.