On Wed, Aug 04 2021, SZEDER Gábor wrote: > On Wed, Aug 04, 2021 at 09:53:02PM +0200, Ævar Arnfjörð Bjarmason wrote: >> >> On Wed, Aug 04 2021, Junio C Hamano wrote: >> >> > Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> writes: >> > >> >>> * ab/test-columns (2021-08-02) 3 commits >> >>> - test-lib.sh: use GIT_TEST_COLUMNS over COLUMNS >> >>> - test-lib-functions.sh: add a test_with_columns function >> >>> - test-lib-functions.sh: rename test_must_fail_acceptable() >> >> >> >> We're going to need this or another solution to the v2.33.0-rc0 >> >> regression in c49a177beca (test-lib.sh: set COLUMNS=80 for --verbose >> >> repeatability, 2021-06-29) before the final v2.33.0. >> > >> > Just a question. Is that true? Wouldn't a system that needs these >> > on top of c49a177beca already break the tests without c49a177beca? >> > >> > IOW, is c49a177beca truly a "regression", or is it merely "a half >> > solution that solves for most but not all platforms"? >> >> Yes, because with c49a177beca your tests only break if you use the >> --verbose option, i.e. if your stderr is connected to a terminal. I.e.: >> >> ./t0500-progress-display.sh --verbose >> >> So in practice it mostly affects git developers who run with --verbose, >> but probably nobody doing a build in the wild. >> >> With c49a177beca they break on e.g.: >> >> /bin/bash ./t0500-progress-display.sh >> >> If your bash is recent enough, so "make test" if you're on a system with >> a recent bash whose /bin/sh is /bin/bash. >> >> This is because post-c49a177beca we don't "unset" COLUMNS anymore, which >> bash takes as license to update it. >> >> So we really do need that series in before the release to avoid that >> common annoyance, a revert of c49a177beca is also possible, i.e. it >> would still leave things broken under --verbose, but that breakage is >> rare and existed before v2.33. >> >> I think given the triviality of the fixes and that the cause is >> well-understood it makes sense to go forward in this case. > > On one hand, there is feedback to be addressed: > > https://public-inbox.org/git/20210802171429.GC23408@xxxxxxxxxx/ I read that a couple of days ago, but managed to forget about it. Sorry, re-rolled with it addressed: https://lore.kernel.org/git/cover-v3-0.3-00000000000-20210804T230335Z-avarab@xxxxxxxxx/ > OTOH, setting the checkwinsize is the truly trivial, minimal, reliable > and uncontroversial fix for this issue, and IMO that should go into > the next release. Addressed below. > This fix in this patch series is not trivial: it introduces yet > another GIT_TEST variable and a helper function that developers will > have to remember to use in the future. Worse, this means that despite > aiming for future proofing I can't consider this approach future > proof, because it's easy to forget about such a rarely used test > helper function, and if anyone introduces yet another test setting > COLUMNS, then that will be prone to similar failures when run with > Bash. How would it be forgotten? If you introduce tests like the ones changed in 1/3 of the series and expect git to pay attention to COLUMNS you'll find that they won't work, because if you set COLUMNS=123 we won't take it over the GIT_TEST_COLUMNS=80 set in test-lib.sh. So it seems like a fairly easy-to-discover thing. You'll grep for that setting and find test_with_columns(). Most tests (such as t0500-progress-display.sh) won't need to concern themselves with the new helper, it's only for those tests that want to check how git itself behaves with a custom COLUMNS value, as opposed to just wanting consistent repeatable results. In any case, I didn't think a helper was needed in this case, it's something Junio requested: https://lore.kernel.org/git/xmqqzgu7b6of.fsf@gitster.g/ ... > I don't think that in this case we should aim for future proofing when > the cost is the additional cognitive load of yet another helper > function. I would instead prefer to go with the really trivial fix > for now and wait whether this issue pops up again with other shell or > terminal, hoping that this issue is a "one-hit-wonder" [1] and it > won't happen ever again. ...I'd be happy to remove the helper if Junio would take that version of the patch; :) But in the topic of the overall approach, I think it's worth future-proofing here mainly because it's useful to be able to reliably run "make test" on old commits for bisecting, which is a property we mostly manage to uphold. By narrowly targeting a fix at one specific shell's cleverness around COLUMNS we'll leave open a window where we'll fail on other shells if they introduce similar cleverness. It hardly seems like a stretch that once bash starts doing that sort of thing other shells might think to follow suit, and all have their own non-standard way to turn it off. You also didn't address the other rationale for it, namely that it's also future-proofing us for submarine breakages in non-git programs which'll understand the new COLUMNS=10, but not GIT_TEST_COLUMNS=80. I.e. should our tests rely on their output, and those programs themselves change how they treat e.g. COLUMNS v.s. TIOCGWINSZ any tests relying on their output will change their behavior.
