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

        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.

ok, sounds reasonable to me; though I do not use this feature,
so my judgement is not as good.

Do we need a test for this behavior?

Thanks,
Stefan