Re: [PATCH v3 2/5] setup: allow for prefix to be passed to git commands

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 17, 2017, 19:17 UTC
Message-ID: <xmqq60j77lx3.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <CAGZ79kZAZeb5rsL80dty_tRM5SDCAXVq_yATpDQREq_vV4Yj+Q@mail.gmail.com>

Stefan Beller <sbeller@google.com> writes:

Show 12 quoted lines

>>         prefix = setup_git_directory_gently_1(nongit_ok);
>> +       env_prefix = getenv(GIT_TOPLEVEL_PREFIX_ENVIRONMENT);
>> +
>> +       if (env_prefix)
>> +               prefix = env_prefix;
>> +
>>         if (prefix)
>>                 setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
>
> so we load that GIT_TOPLEVEL_PREFIX_ENVIRONMENT prefix
> first, such that we essentially copy it into GIT_PREFIX_ENVIRONMENT,
> such that e.g. aliased commands will know about the superprefix, too.

If the aliased commands or anything else spawned from this process is happy with GIT_PREFIX set to the outside of the current repository, doing this setenv() is OK. If you are in ~/dir1, and your repository is in ~/repos/repo1, and if you somehow had a way to run your "git" inside ~/repos/repo1 without doing any chdir(2), then you are essentially setting ../../dir1/ as GIT_PREFIX for that "git" invocation (this has nothing to do with submodules).

But if your "git" is fine with GIT_PREFIX pointing outside the root level of the working tree of the current repository like that, do we even need a separate toplevel prefix environment, I have to wonder?

That is, if this "if TOPLEVEL_PREFIX environment is there, set it to local variable prefix and export it as GIT_PREFIX" is expected to work correctly for anything that would inherit that GIT_PREFIX, then we should be able to invoke the "git" that got TOPLEVEL_PREFIX without setting that environment, but instead setting the same value to GIT_PREFIX and we should get the same behaviour, no?