[PATCH 2/2] test-lib: disable trace when test is not verbose

The "-x" test-script option turns on the shell's "-x" tracing, which can help show why a particular test is failing. Unfortunately, this can create false negatives in some tests if they invoke a shell function with its stderr redirected. t5512.10 is such a test, as it does:

    test_must_fail git ls-remote refs*master >actual 2>&1 &&
    test_cmp exp actual

The "actual" file gets the "-x" trace for the test_must_fail function, which prevents it from matching the expected output.

There's no way to avoid this without managing the trace flag inside each sub-function, which isn't really a workable solution. But unless you specifically care about t5512.10, we can work around it by enabling tracing only for the specific tests we want.

You can already do:

    ./t5512-ls-remote.sh -x --verbose-only=16

to see the trace only for a specific test. But that doesn't _disable_ the tracing in the other tests; it just sends it to /dev/null. However, there's no point in generating a trace that the user won't see, so we can simply disable tracing whenever it doesn't have a matching verbose flag.

The normal case of just "./t5512-ls-remote.sh -x" stays the same, as "-x" already implies "--verbose" (and "--verbose-only" overrides "--verbose", which is why this works at all). And for our test, we need only check $verbose, as maybe_setup_verbose will have already set that flag based on the $verbose_only list).

Signed-off-by: Jeff King <peff@peff.net>
---
 t/test-lib.sh | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)