Re: [PATCH] format-patch: escape "From " lines recognized by mailsplit

[Eric Wong <e@80x24.org>]

Junio C Hamano <gitster@pobox.com> wrote:
> Junio C Hamano <gitster@pobox.com> writes:
> > Eric Wong <e@80x24.org> writes:
> >
> >> Users have mistakenly copied "From " lines into commit messages
> >> in the past, and will certainly make the same mistakes in the
> >> future.  Since not everyone uses mboxrd, yet, we should at least
> >> prevent miss-split mails by always escaping "From " lines based
> >> on the check used by mailsplit.
> >>
> >> mailsplit will not perform unescaping by default, yet, as it
> >> could cause further invocations of format-patch from old
> >> versions of git to generate bad output.  Propagating the mboxo
> >> escaping is preferable to miss-split patches.  Unescaping may
> >> still be performed via "--mboxrd".
> >
> > As a tool to produce mbox file, quoting like this in format-patch
> > output may make sense, I would think, but shouldn't send-email undo
> > this when sending individual patches?
> 
> Also, doesn't it break "git rebase" (non-interactive), or anything
> that internally runs format-patch to individual files and then runs
> am on each of them, anything that knows that each output file from
> format-patch corresponds to a single change and there is no need to
> split, badly if we do this unconditionally?

Yes, rebase should probably unescape is_from_line matches.

Anything which spawns an editor should probably warn/reprompt
users on is_from_line() matches, too, to prevent user errors
from sneaking in.

> IOW, shouldn't this be an optional feature to format-patch that is
> triggered by passing a new command line option that currently nobody
> is passing?

I added --pretty=mboxrd as the optional feature for this reason.
It'll take a while for people to start using it (or perhaps make
it the default in git 3.0).
In the meantime, I would prefer extra ">" being injected rather
than breaking mailsplit completely.