Re: [PATCH] sequencer.c: terminate the last line of author-script properly

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Phillip,

On Thu, 19 Jul 2018, Phillip Wood wrote:

> On 18/07/18 18:17, Junio C Hamano wrote:
> > Phillip Wood <phillip.wood@talktalk.net> writes:
> > 
> >>> (I think we had code to do so in "git am"
> >>> that was rewritten in C first).
> >>
> >> The code in builtin/am.c doesn't try to write valid posix shell (if
> >> one assumes it is the only consumer of the author script then it
> >> doesn't need to) which results in simpler code, but external scripts
> >> cannot safely eval it anymore.
> > 
> > Are you sure about that? If so we probably should see if we can fix> the writer, and better yet, if we can share code with the writer
> > discussed here, as presumably we are fixing it in this thread.
> > 
> > But I do not see how builtin/am.c::write_author_script() would
> > produce something that would not eval correctly.  sq_quote_buf() was
> > introduced specifically to write correct string for shell's
> > consumption.
> 
> You're right, I'm not sure how I missed the calls to sq_quote_buf()
> yesterday, sharing the am code with the sequencer would clean things up
> nicely.

No, actually Phillip was right. The `author-script` file written by
`git-am` was always an implementation detail, and as there was no
(intended) way to call shell scripts while running `git-am`, the only
shell script to intentionally use `author-script` was `git-am` itself.

Ever since `git-am` is a builtin, the `author-script` file format could be
changed, because it is an implementation detail, no more nor less, and I
think it *should* be changed, too. We're spending useless cycles on
quoting and dequoting, when writing a NUL-separated list of var=value
pairs would be totally sufficient to our ends.

Ciao,
Dscho