Re: [PATCH v4] git-rebase--interactive.sh: add config option for custom instruction format

[Mike Rappazzo <rappazzo@gmail.com>]

On Fri, Jun 12, 2015 at 6:05 PM, Junio C Hamano <gitster@pobox.com> wrote:
> But because you overwrite the $message variable you read from the
> original insn sheet (which uses the custom format) and compute $rest
> based on the default "%s" and store that in "$1.sq", lines in
> "$1.sq" do not know anything about the custom format, do they?
>
> And then they are injected to appropriate places in "$1.rearranged".
> Moved lines in the the rearranged result would end up written in the
> default "%s" format, no?
>
> That was the part that made me uneasy.
>
> I do not think that is a bug worth fixing, but I view it as a sign
> that fundamentally the autosquash and the idea of configurable
> format do not mesh well with each other.

My understanding of the rearrange_squash function is this:
There are two loops.  The first loop collects the commits which should
be moved (squashed).  The second loop re-constructs the instruction
list using the info from the first loop.

In the second loop, I changed it to recalculate the presented message
when the re-ordered commit is added:

+       if test -n "${format}"
+       then
+            msg_content=$(git log -n 1 --format="${format}" ${squash})


That is the "$rest".

I have patched my locally installed `git-rebase--interactive` with
these changes, and I did see the proper rearrangement of commits with
the custom formatted message.