Re: [PATCH 1/2] clone: respect the settings in $HOME/.gitconfig and /etc/gitconfig

From: Daniel Barkalow <barkalow@iabervon.org>
Date: Jun 30, 2008, 03:47 UTC
Message-ID: <alpine.LNX.1.00.0806292320300.19665@iabervon.org>
In-Reply-To: <7vabh390sc.fsf@gitster.siamese.dyndns.org>

On Sun, 29 Jun 2008, Junio C Hamano wrote:

Show 46 quoted lines

> Daniel Barkalow <barkalow@iabervon.org> writes:
> 
> > ... In any case, I don't think "git clone" is at 
> > all special with respect to GIT_CONFIG.
> 
> I think "git init" and "git clone" are very special with respect to
> GIT_CONFIG.
> 
>  * When "init" is run to create a new repository and initialize it, the
>    user would want the initial set of configuration populated in the
>    configuration file _for that repository_.  There however may be some
>    customization that affects the way how "init" operates, which might be
>    taken from $HOME/.gitconfig.  The meaning of GIT_CONFIG can get fuzzy
>    here.  Possibilities:
> 
>    (1) Instead of $HOME/.gitconfig (or /etc/gitconfig), the user might
>        want such customizations to be read from the file specified by
>        GIT_CONFIG.  But the user wants to make the resulting new
>        repository usable without any custom GIT_CONFIG set (i.e. its
>        $GIT_DIR/config will be the place the configuration is written).
> 
>    (2) The user may want to create a new repository that cannot be used
>        with GIT_CONFIG (for some strange reason), i.e. no $GIT_DIR/config
>        for the repository, and GIT_CONFIG is used to specify where that
>        separate configuration file for the new repository is.  The way
>        "init" operates does not come from that configuration file that is
>        to be created but from elsewhere.
> 
>  * When "clone" is run, the same confusion as initializing "init" applies.
>    In addition, custom GIT_CONFIG to read customizations for behaviour of
>    "init" and "fetch" that is done internally by "clone" would play larger
>    role.
> 
>  * When "init" is run to reinitialize an existing repository, it is not
>    special in any way with respect to GIT_CONFIG, compared to other
>    commands.  The GIT_CONFIG names the configuration for that existing
>    repository, so we read from it and write to it.
> 
> I personally think the case (2) is a very narrow special case that I do
> not think of any sane reason to even wanting to do so.  IOW, "you _could_
> interpret the presense of GIT_CONFIG that the user may want to do so, but
> why?"  (1) is also probably not very sensible but it makes more sense.
> 
> I think Dscho's original patch would support the semantics (1) and it is
> probably much saner than (2) which is your version does (if I am reading
> the two patches correctly).

A bit more information on this. There are 3 possible states for GIT_CONFIG:

 (1) Not set; things work normally

 (2) Set to ".git/config"; things work normally except that no global or 
     system config is used

 (3) Set to something else; anything expecting to read or write 
     configuration related to the repo will misbehave

Historically, clone worked entirely in state (2) regardless of what the user asked for. Everything else left it how the user had it. Dscho's patch changes it to initialize the repo in state (2) and fetch in state (1), still ignoring what the user set. My patch changes it to leave it how the user has it.

Now, clone writes to the config file before reading any configuration, so, if it's going to write to ".git/config" instead of $GIT_CONFIG, it can't read from $GIT_CONFIG either. So there's no way (outside of redesigning config.c) to make GIT_CONFIG useful for "clone" in particular. Other commands don't clear it, so they just misbehave if it's set. We can be pretty sure, therefore, that users will put it either in (1) or (if they want GIT_CONFIG_NO_GLOBAL and don't know about it and aren't worried about "clone") in (2). So the practical difference between my patch and Dscho's is that, with mine, ~/.gitconfig would affect the initialization step if it actually used any config settings.

If you want anything more clever to happen, that requires config.c changes of some sort to provide a state where it reads some additional file but writes the repo's usual one, and probably *also* *my* patch, so that clone doesn't blow away the user's setting before config.c gets it.

	-Daniel
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