Re: [RFC/PATCH] git: expand user path in --git-dir

[Michael J Gruber <git@drmicha.warpmail.net>]

Jeff King venit, vidit, dixit 24.09.2012 16:52:
> On Mon, Sep 24, 2012 at 02:57:20PM +0200, Michael J Gruber wrote:
> 
>> Currently, all paths in the config file are subject to tilde expansion
>> for user paths while the argument to --git-dir is not expanded, and
>> neither are paths in the environment such as GIT_DIR. From the user
>> perspective, though, the two commands
>>
>> GIT_DIR=~user/foo git command
>> git --git-dir=~user/foo command
>>
>> currently behave differently because in the first case the shell would
>> perform tilde expansion, but not in the second. Also, one may argue that
>> specifying '--git-dir=' is like specifying a config variable (which
>> cannot exist for this purpose).
>>
>> Thus, make arguments to '--git-dir' undergo tilde expansion.
>> ---
>> So, here's a simple patch implementing tilde expansion for --git-dir. It passes
>> all tests. It's done doing the expansion on the setting side.
>>
>> Alternatively, one might do it on the getting side, i.e. when reading GIT_DIR,
>> so that paths passed directly through the environment undergo tilde expansion
>> as well. We don't do this for any environment variable yet, so I didn't go
>> that far.
> 
> Keep in mind that every layer of expansion you add is a layer of quoting
> somebody else must do in order to pass through certain paths.  I will
> admit that putting a "~" into a path is relatively uncommon, but this
> patch is a regression for anybody who does so with --git-dir (they will
> now need to quote the "~" against not just their shell, but against
> git). Expanding environment variables like GIT_DIR means that we would
> also need to quote things we put into GIT_DIR.

...as far as "~" is concerned, yes. We don't do a full expansion like
the shell does (or doesn't).

Probably "--git-dir" is hidden well enough to be for the initiated only.
As for the other path options, we can always blame bash. It's got its
name for a reason ;)

Michael