From: "SZEDER Gábor" <szeder.dev@gmail.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
Jeff King <peff@peff.net>,
Derrick Stolee <derrickstolee@github.com>,
Taylor Blau <me@ttaylorr.com>
Subject: Re: [PATCH v4 0/3] test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFD
Date: Mon, 21 Feb 2022 22:03:19 +0100 [thread overview]
Message-ID: <20220221210319.GA1658@szeder.dev> (raw)
In-Reply-To: <220221.86v8x89ebo.gmgdl@evledraar.gmail.com>
On Mon, Feb 21, 2022 at 08:52:18PM +0100, Ævar Arnfjörð Bjarmason wrote:
>
> [Junio: If you'd like to pick up this series it still cleanly applies,
> and merges cleanly with "seen"]
>
> On Mon, Dec 13 2021, SZEDER Gábor wrote:
>
> Sorry about the late reply, things getting lost around the holidays
> etc.
>
> > On Mon, Dec 13, 2021 at 02:38:33AM +0100, Ævar Arnfjörð Bjarmason wrote:
> >> A re-arrangement-only change to v3[1]. The previous 2/2 is now split
> >> into two commits, as requested by SZEDER[2] in the removal of
> >> BASH_XTRACEFD is now its own commit & the rationale for doing so is
> >> outlined in detail.
> >
> > I'm afraid I wasn't clear. What I meant was that if we were to remove
> > BASH_XTRACEFD, then it should be done its own commit.
>
> Aside from whether you think removing it is a good idea, isn't that what
> this v4 does?
Well, yes, but I now realize that I wasn't sufficiently clear the
second time around, either, and emphasis doesn't travel well over
email. What I meant was that: _if_ at all we were to remove it, then
it should be a separate patch, but since we should most definitely
keep it, those hunks should be simply dropped.
> In 1/3 I fix -x under non-BASH_XTRACEFD, 2/3 removes test_untraceable,
> and 3/3 the use of BASH_XTRACEFD.
>
> > But again: BASH_XTRACEFD is the only simple yet reliable and robust
> > way to get -x trace from our tests, so do not remove it.
>
> Just to tie off this loose end, I re-read the thread ending in [1] (sent
> after this reply of yours) and I think my [1] addresses this.
It doesn't at all; "if CI passes without it, then we can remove it" is
not a convincing argument.
> Maybe you still disagree, but I don't see how that squares with
> "reliable and robust" here.
>
> I.e. unless we're talking about carrying bash-specific code in the test
> suite we can't make any real use of the feature, as our tests will need
> to be compatible with other POSIX shells.
>
> I mean, the code changed in 1/3 *was* that bash-specific code, but as
> that change shows it was rather easily made non-bash-specific. And
> unless we think we'll add other bash-specific tests (I don't see why,
> the cross-shell -x support is rather easy to do) ....
>
> 1. https://lore.kernel.org/git/211216.864k78bsjs.gmgdl@evledraar.gmail.com/
>
> >> 1. https://lore.kernel.org/git/cover-v3-0.2-00000000000-20211210T100512Z-avarab@gmail.com/
> >> 2. https://lore.kernel.org/git/20211212201441.GB3400@szeder.dev/
> >>
> >> Ævar Arnfjörð Bjarmason (3):
> >> t1510: remove need for "test_untraceable", retain coverage
> >> test-lib.sh: remove the now-unused "test_untraceable" facility
> >> test-lib.sh: remove "BASH_XTRACEFD"
> >>
> >> t/README | 3 --
> >> t/t1510-repo-setup.sh | 85 +++++++++++++++++++++----------------------
> >> t/test-lib.sh | 66 ++++-----------------------------
> >> 3 files changed, 49 insertions(+), 105 deletions(-)
> >>
> >> Range-diff against v3:
> >> 1: 7876202c5b0 = 1: 9e7b089dc50 t1510: remove need for "test_untraceable", retain coverage
> >> -: ----------- > 2: 60883fd95cb test-lib.sh: remove the now-unused "test_untraceable" facility
> >> 2: a7fc794e20d ! 3: 8b5ae33376e test-lib.sh: remove the now-unused "test_untraceable" facility
> >> @@ Metadata
> >> Author: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> >>
> >> ## Commit message ##
> >> - test-lib.sh: remove the now-unused "test_untraceable" facility
> >> + test-lib.sh: remove "BASH_XTRACEFD"
> >>
> >> - In the preceding commit the use of "test_untraceable=UnfortunatelyYes"
> >> - was removed from "t1510-repo-setup.sh" in favor of more narrow
> >> - redirections of the output of specific commands (and not entire
> >> - sub-shells or functions).
> >> + Stop setting "BASH_XTRACEFD=4" to direct "-x" output to file
> >> + descriptor 4 under bash.
> >>
> >> - This is in line with the fixes in the series that introduced the
> >> - "test_untraceable" facility. See 571e472dc43 (Merge branch
> >> - 'sg/test-x', 2018-03-14) for the series as a whole, and
> >> - e.g. 91538d0cde9 (t5570-git-daemon: don't check the stderr of a
> >> - subshell, 2018-02-24) for a commit that's in line with the changes in
> >> - the preceding commit.
> >> + When it was added in d88785e424a (test-lib: set BASH_XTRACEFD
> >> + automatically, 2016-05-11) it was needed as a workaround for various
> >> + tests that didn't pass cleanly under "-x".
> >>
> >> - We've thus solved the TODO item noted when "test_untraceable" was
> >> - added to "t1510-repo-setup.sh" in 58275069288 (t1510-repo-setup: mark
> >> - as untraceable with '-x', 2018-02-24).
> >> + Most of those were later fixed in 71e472dc43 (Merge branch
> >> + 'sg/test-x', 2018-03-14), and in the preceding commits we've fixed the
> >> + final remaining and removed the "test_untraceable" facility.
> >>
> >> - So let's remove the feature entirely. Not only is it currently unused,
> >> - but it actively encourages an anti-pattern in our tests. We should be
> >> - testing the output of specific commands, not entire subshells or
> >> - functions.
> >> + The reason we don't need this anymore is becomes clear from reading
> >> + the rationale in d88785e424a and applying those arguments to the
> >> + current state of the codebase. In particular it said (with "this" and
> >> + "it" referring to the problem of tests failing under "-x"):
> >>
> >> - That the "-x" output had to be disabled as a result is only one
> >> - symptom, but even under bash those tests will be harder to debug as
> >> - the subsequent check of the redirected file will be far removed from
> >> - the command that emitted the output.
> >> + "there here isn't a portable or scalable solution to this [...] we
> >> + can work around it by pointing the "set -x" output to our
> >> + descriptor 4"
> >>
> >> - Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> >> + And finally that:
> >>
> >> - ## t/README ##
> >> -@@ t/README: appropriately before running "make". Short options can be bundled, i.e.
> >> - -x::
> >> - Turn on shell tracing (i.e., `set -x`) during the tests
> >> - themselves. Implies `--verbose`.
> >> -- Ignored in test scripts that set the variable 'test_untraceable'
> >> -- to a non-empty value, unless it's run with a Bash version
> >> -- supporting BASH_XTRACEFD, i.e. v4.1 or later.
> >> -
> >> - -d::
> >> - --debug::
> >> + "Automatic tests for our "-x" option may be a bit too meta"
> >> +
> >> + Those tests are exactly what we've had since aedffe95250 (travis-ci:
> >> + run tests with '-x' tracing, 2018-02-24), so punting on fixing issues
> >> + with "-x" by using "BASH_XTRACEFD=4" isn't needed anymore, we're now
> >> + committing to maintaining the test suite in a way that won't break
> >> + under "-x".
> >> +
> >> + We could retain "BASH_XTRACEFD=4" anyway, but doing so is bad because:
> >> +
> >> + 1) Since we're caring about "-x" passing in CI under "dash" on Ubuntu
> >> + using "BASH_XTRACEFD=4" will amount to hiding an error we'll run
> >> + into eventually. Tests will pass locally with "bash", but fail in
> >> + CI with "dash" (or under other non-"bash" shells).
> >> +
> >> + 2) As the amended code in "test_eval_" shows (an amended revert to
> >> + the pre-image of d88785e424a) it's simpler to not have to take
> >> + this "bash" special-case into account.
> >> +
> >> + Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> >>
> >> ## t/test-lib.sh ##
> >> -@@ t/test-lib.sh: then
> >> - exit
> >> - fi
> >> -
> >> --if test -n "$trace" && test -n "$test_untraceable"
> >> --then
> >> -- # '-x' tracing requested, but this test script can't be reliably
> >> -- # traced, unless it is run with a Bash version supporting
> >> -- # BASH_XTRACEFD (introduced in Bash v4.1).
> >> -- #
> >> -- # Perform this version check _after_ the test script was
> >> -- # potentially re-executed with $TEST_SHELL_PATH for '--tee' or
> >> -- # '--verbose-log', so the right shell is checked and the
> >> -- # warning is issued only once.
> >> -- if test -n "$BASH_VERSION" && eval '
> >> -- test ${BASH_VERSINFO[0]} -gt 4 || {
> >> -- test ${BASH_VERSINFO[0]} -eq 4 &&
> >> -- test ${BASH_VERSINFO[1]} -ge 1
> >> -- }
> >> -- '
> >> -- then
> >> -- : Executed by a Bash version supporting BASH_XTRACEFD. Good.
> >> -- else
> >> -- echo >&2 "warning: ignoring -x; '$0' is untraceable without BASH_XTRACEFD"
> >> -- trace=
> >> -- fi
> >> --fi
> >> - if test -n "$trace" && test -z "$verbose_log"
> >> - then
> >> - verbose=t
> >> @@ t/test-lib.sh: else
> >> exec 4>/dev/null 3>/dev/null
> >> fi
> >> --
> >> 2.34.1.1024.g573f2f4b767
> >>
>
> o
next prev parent reply other threads:[~2022-02-21 21:04 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-29 13:47 [PATCH 0/2] Set GIT_TRACE2_EVENT_NESTING in test-lib.sh Derrick Stolee via GitGitGadget
2021-11-29 13:47 ` [PATCH 1/2] test-lib.sh: set GIT_TRACE2_EVENT_NESTING Derrick Stolee via GitGitGadget
2021-11-29 14:12 ` Ævar Arnfjörð Bjarmason
2021-11-29 18:28 ` Junio C Hamano
2021-11-29 18:32 ` Junio C Hamano
2021-11-29 13:47 ` [PATCH 2/2] t/t*: remove custom GIT_TRACE2_EVENT_NESTING Derrick Stolee via GitGitGadget
2021-11-29 18:40 ` [PATCH 0/2] Set GIT_TRACE2_EVENT_NESTING in test-lib.sh Jeff King
2021-11-29 18:44 ` Jeff King
2021-11-30 0:04 ` Taylor Blau
2021-11-30 15:34 ` Derrick Stolee
2021-11-30 22:43 ` Jeff Hostetler
2021-12-01 19:46 ` Jeff King
2021-11-29 20:13 ` [PATCH] test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFD Ævar Arnfjörð Bjarmason
2021-11-29 23:23 ` Eric Sunshine
2021-11-30 21:08 ` Jeff King
2021-11-30 21:50 ` Ævar Arnfjörð Bjarmason
2021-11-30 22:44 ` SZEDER Gábor
2021-12-01 14:06 ` Ævar Arnfjörð Bjarmason
2021-12-01 19:38 ` Jeff King
2021-12-01 18:38 ` Junio C Hamano
2021-12-01 20:11 ` [PATCH v2 0/2] " Ævar Arnfjörð Bjarmason
2021-12-01 20:11 ` [PATCH v2 1/2] t1510: remove need for "test_untraceable", retain coverage Ævar Arnfjörð Bjarmason
2021-12-02 19:16 ` SZEDER Gábor
2021-12-02 19:28 ` SZEDER Gábor
2021-12-10 9:47 ` Jeff King
2021-12-10 10:08 ` Ævar Arnfjörð Bjarmason
2022-02-06 21:40 ` SZEDER Gábor
2021-12-01 20:11 ` [PATCH v2 2/2] test-lib.sh: remove the now-unused "test_untraceable" facility Ævar Arnfjörð Bjarmason
2021-12-10 10:07 ` [PATCH v3 0/2] test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFD Ævar Arnfjörð Bjarmason
2021-12-10 10:07 ` [PATCH v3 1/2] t1510: remove need for "test_untraceable", retain coverage Ævar Arnfjörð Bjarmason
2021-12-10 10:07 ` [PATCH v3 2/2] test-lib.sh: remove the now-unused "test_untraceable" facility Ævar Arnfjörð Bjarmason
2021-12-12 16:32 ` SZEDER Gábor
2021-12-12 17:06 ` Ævar Arnfjörð Bjarmason
2021-12-12 20:14 ` SZEDER Gábor
2021-12-13 18:51 ` Junio C Hamano
2021-12-14 16:43 ` Jeff King
2021-12-15 17:05 ` Junio C Hamano
2021-12-15 17:17 ` Jeff King
2021-12-15 17:32 ` Junio C Hamano
2021-12-16 13:04 ` Ævar Arnfjörð Bjarmason
2021-12-13 1:38 ` [PATCH v4 0/3] test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFD Ævar Arnfjörð Bjarmason
2021-12-13 1:38 ` [PATCH v4 1/3] t1510: remove need for "test_untraceable", retain coverage Ævar Arnfjörð Bjarmason
2021-12-13 1:38 ` [PATCH v4 2/3] test-lib.sh: remove the now-unused "test_untraceable" facility Ævar Arnfjörð Bjarmason
2021-12-13 1:38 ` [PATCH v4 3/3] test-lib.sh: remove "BASH_XTRACEFD" Ævar Arnfjörð Bjarmason
2022-02-21 23:11 ` SZEDER Gábor
2022-02-22 15:14 ` Ævar Arnfjörð Bjarmason
2021-12-13 5:43 ` [PATCH v4 0/3] test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFD SZEDER Gábor
2022-02-21 19:52 ` Ævar Arnfjörð Bjarmason
2022-02-21 21:03 ` SZEDER Gábor [this message]
2022-02-21 22:41 ` Ævar Arnfjörð Bjarmason
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