Subject: Re: [PATCH 2/2] config: allow specifying config entries via envvar pairs

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Wed, 18 Nov 2020 14:49:39 +0100

On Tue, Nov 17 2020, Junio C Hamano wrote:

> Patrick Steinhardt <[email-masked]> writes:
>
>>> I especially do not think we want to read from unbounded number of
>>> GIT_CONFIG_KEY_<N> variables like this patch does.  How would a
>>> script cleanse its environment to protect itself from stray such
>>> environment variable pair?  Count up from 1 to forever?  Run "env"
>>> and grep for "GIT_CONFIG_KEY_[0-9]*=" (the answer is No.  What if
>>> some environment variables have newline in its values?)
>>
>> You only have to unset `GIT_CONFIG_KEY_1` as the parser will stop
>> iterating on the first missing key. More generally, if you set `n` keys,
>> it's sufficient to unset key `n+1`.
>
> Yes, but those who want to set N keys would likely to be content
> with setting 1..N and happily forget unsetting N+1, and that is
> where "how would one cleanse the environment to give a clean slate?"
> comes from.

Not as an argument from whataboutism, but just to note a bug/existing
prior art:

Nobody in this thread has mentioned GIT_PUSH_OPTION_* which works pretty
much like Patrick's suggestion, and it looks like --local-env-vars
misses those:

    $ GIT_PUSH_OPTION_0=foo GIT_PUSH_OPTION_COUNT=20 git rev-parse --local-env-vars | grep GIT_PUSH
    $

I haven't tested this, but I expect there's a bug where a push hook
itself does a local push to another repo and that repo has a hook, that
the push options are erroneously carried forward to the sub-process.

That might also be a feature, depending on your point of view.