Re: [PATCH] test-lib: whitelist GIT_TR2_* in the environment

> Add GIT_TR2_* to the whitelist of environment variables that we don't
> clear when running the test suite.
> 
> This allows us to use the test suite to produce trace2 test data,
> which is handy to e.g. write consumers that collate the trace data
> itself.
> 
> One caveat here is that we produce trace output for not *just* the
> tests, but also e.g. from this line in test-lib.sh:
> 
>      # It appears that people try to run tests without building...
>      "${GIT_TEST_INSTALLED:-$GIT_BUILD_DIR}/git$X" >/dev/null
>      [...]
> 
> I consider this not just OK but a feature. Let's log *all* the git
> commands we're going to execute, not just those within
> test_expect_*().
> 
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>   t/test-lib.sh | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/t/test-lib.sh b/t/test-lib.sh
> index 562c57e685..f6318c54c9 100644
> --- a/t/test-lib.sh
> +++ b/t/test-lib.sh
> @@ -379,6 +379,7 @@ unset VISUAL EMAIL LANGUAGE COLUMNS $("$PERL_PATH" -e '
>   	my @env = keys %ENV;
>   	my $ok = join("|", qw(
>   		TRACE
> +		TR2_
>   		DEBUG
>   		TEST
>   		.*_TEST
>