Re: [PATCH] Add two grep config options

Junio C Hamano venit, vidit, dixit 26.03.2011 00:25:

Joe Ratterman [off-list ref] writes:

quoted

grep.extended-regexp: Enabling this boolean option has the same effect
as adding "-E" to all "git grep " instantiations.  This can be
disabled by specifying "--no-extended-regexp" on a particular call.

grep.line-numbers: Enabling this boolean option has the same effect as
adding "-n" to all "git grep " instantiations.

Signed-off-by: Joe Ratterman <redacted>

Thanks.

Things to consider:

 - Apply this patch on top of "master",run "git shortlog v1.7.4..HEAD",
   store the output somewhere, and imagine reading that 2 months from now.
   Does a single line in the output about this patch sufficiently tell you
   what it was about?

 - Configuration variables are spelled without hyphens between words (you
   can see "gui.commitmsgwidth" in the context of the patch you sent and
   notice that it is not "gui.commit-msg-width").

 - This will break scripts people have written, knowing that they can rely
   on "grep" they wrote without giving "-E" from their command line will
   use BRE, and force them to update the script with --no-extended-regexp
   for no good reason.  Worse yet, there isn't even --no-line-numbers
   supported to defeat grep.linenumbers configuration to protect such
   scripts.

   I understand that some people would feel that the convenience would
   outweigh the risk of script breakage in this particular case, and I am
   sympathetic to the cause, but I still have to point it out.  Is there
   anything we can do to mitigate the risk somehow?

This comes up again and again, and I feel that rather than adding config
options one by one, we should either allow aliases for standard commands
and/or setting default options depending on the mode (ui use vs.
scripting use), so to say a companion to "git -c n=v" which allows

git config ui.grep "-E -n"

I.e. just like "git -c n=v <cmd>" sets up pseudo config before running
cmd, our wrapper could augment argv from "ui.<cmd>".

We could safeguard scripts from this by

- checking istty and
- checking env for GIT_PLUMBING

and setting the latter in git-sh-setup.sh. After a long migration phase,
we could skip the first (fragile) check.

Michael