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From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Jeff King <peff@peff.net>
Cc: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2 3/5] tests: turn GPG, GPGSM and RFC1991 into lazy prereqs
Date: Mon, 30 Mar 2020 20:39:08 +0200 (CEST)	[thread overview]
Message-ID: <nycvar.QRO.7.76.6.2003302027240.46@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <20200327091004.GA610157@coredump.intra.peff.net>

Hi Peff,

On Fri, 27 Mar 2020, Jeff King wrote:

> On Thu, Mar 26, 2020 at 03:27:19PM +0100, Johannes Schindelin wrote:
>
> > > OK. This looks good, even if I cannot help feel that my earlier patch
> > > was perfectly sufficient. ;)
> >
> > The mistake is all mine. I had totally missed that you turned GPG into a
> > lazy prereq. So I had my patch finalized already before you pointed my
> > nose at that fact.
> >
> > Sorry about that.
>
> No problem. And I hope my review didn't sound too passive-aggressive
> with the "well, in MY version we did this...".

FWIW I failed to interpret anything in your reply as passive-aggressive,
probably because I am just too used to receive competent, helpful and
friendly replies from you.

> I focused on the differences because those were the parts that were new
> (and therefore interesting) to me. But I don't think any of them are too
> important either way.

To me, it all sounded like a constructive discussion we had, and since you
already had a working patch that did something very similar to mine, it
made sense to look at their differences.

> > - Since this code is outside of a function, `return` felt like the wrong
> >   semantic concept to me. And indeed, I see this (rather scary) part in
> >   Bash's documentation of `return` (I did not even bother to look at the
> >   POSIX semantics, it scared me so much):
> >
> >       The return status is non-zero if `return` is supplied a non-numeric
> >       argument, or is used outside a function and not during execution of
> >       a script by `.` or `source`.
> >
> >   So: the `1` is totally ignored in this context. That alone is reason
> >   enough for me to completely avoid it, and use `exit` instead.
>
> I agree the portability rules there are scary, but none of that applies
> because we _are_ in a function: test_eval_inner_(). This behavior is
> intentional and due to a7c58f280a (test: cope better with use of return
> for errors, 2011-08-08). I thought we specifically advertised this
> feature in t/README, but I can't seem to find it.
>
> So my perspective was the opposite of yours: "return" is the officially
> sanctioned way to exit early from a test snippet, and "exit" only
> happens to work because of the undocumented fact that lazy prereqs
> happen in a subshell. But it turns out neither was documented. :)

Can a subshell inside a function cause a `return` from said function? I
don't think so, but let's put that to a test:

	function return_from_a_subshell () {
		echo before
		(echo subshell; return; echo unreachable)
		echo after $?
	}

Let's run that.

	$ return_from_a_subshell
	before
	subshell
	after 0

To me, the fact that that `return` does not return from the function, but
only exits the subshell, in my mind lends more credence to the idea that
`exit` is more appropriate in this context than `return`.

For shiggles, I also added that `$?` because I really, _really_ wanted to
know whether my reading of GNU Bash's documentation was correct, and it
appears I was mistaken: apparently `return` used outside a function does
_not_ cause a non-zero exit code.

> > > In mine I put the test_have_prereq outside the lazy prereq.
> >
> > That makes it essentially a non-lazy prereq.
> >
> > > I don't think it really matters either way (when we later ask if GPGSM
> > > is set, there is no difference between nobody having defined it, and
> > > having a lazy definition that said "no").
> >
> > The difference is when running a test with `--run=<n>` where `<n>` refers
> > to a test case that requires neither GPG nor GPGSM or RFC1991. My version
> > will not evaluate the GPG prereq, yours still will.
>
> Yes. Part of the reason I kept mine as it was is because it matched the
> original behavior better (and I was really only using a lazy prereq
> because we didn't have a non-lazy version). But there's really no reason
> _not_ to be lazy, so as long as it isn't breaking anything I think
> that's a better way forward. (And if it is breaking something, that
> something should be fixed).

I'm glad you agree!

Thanks,
Dscho

  parent reply	other threads:[~2020-03-30 18:39 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-23 13:09 [PATCH 0/2] Enable GPG in the Windows part of the CI/PR builds Johannes Schindelin via GitGitGadget
2020-03-23 13:09 ` [PATCH 1/2] tests(gpg): allow the gpg-agent to start on Windows Johannes Schindelin via GitGitGadget
2020-03-23 17:46   ` Junio C Hamano
2020-03-24 19:55     ` Johannes Schindelin
2020-03-24 20:59       ` Junio C Hamano
2020-03-24 22:26         ` Johannes Schindelin
2020-03-24 23:40           ` Junio C Hamano
2020-03-23 13:09 ` [PATCH 2/2] tests(gpg): increase verbosity to allow debugging Johannes Schindelin via GitGitGadget
2020-03-23 17:32   ` Jeff King
2020-03-23 18:04     ` Jeff King
2020-03-23 19:21       ` Junio C Hamano
2020-03-23 20:15         ` Jeff King
2020-03-23 21:28           ` Junio C Hamano
2020-03-23 21:31             ` Jeff King
2020-03-24 21:41               ` Johannes Schindelin
2020-03-24 22:05                 ` Jeff King
2020-03-24 22:25                   ` Johannes Schindelin
2020-03-24 22:33                     ` Jeff King
2020-03-25  5:41 ` [PATCH v2 0/5] Enable GPG in the Windows part of the CI/PR builds Johannes Schindelin via GitGitGadget
2020-03-25  5:41   ` [PATCH v2 1/5] tests(gpg): allow the gpg-agent to start on Windows Johannes Schindelin via GitGitGadget
2020-03-25  5:41   ` [PATCH v2 2/5] t/lib-gpg.sh: stop pretending to be a stand-alone script Johannes Schindelin via GitGitGadget
2020-03-26  8:21     ` Jeff King
2020-03-26 13:48       ` Johannes Schindelin
2020-03-26 19:31       ` Junio C Hamano
2020-03-25  5:41   ` [PATCH v2 3/5] tests: turn GPG, GPGSM and RFC1991 into lazy prereqs Johannes Schindelin via GitGitGadget
2020-03-25 17:25     ` Junio C Hamano
2020-03-26  8:35     ` Jeff King
2020-03-26 14:27       ` Johannes Schindelin
2020-03-27  9:10         ` Jeff King
2020-03-27 17:44           ` Junio C Hamano
2020-03-27 20:24             ` Eric Sunshine
2020-03-27 21:37               ` Junio C Hamano
2020-03-28 10:58                 ` Jeff King
2020-03-28 10:54             ` Jeff King
2020-03-28 23:49               ` [PATCH v2] t/README: suggest how to leave test early with failure Junio C Hamano
2020-03-29  7:23                 ` Eric Sunshine
2020-03-29 14:33                 ` Jeff King
2020-03-30 18:39           ` Johannes Schindelin [this message]
2020-03-31  9:34             ` [PATCH v2 3/5] tests: turn GPG, GPGSM and RFC1991 into lazy prereqs Jeff King
2020-03-25  5:41   ` [PATCH v2 4/5] tests: do not let lazy prereqs inside `test_expect_*` turn off tracing Johannes Schindelin via GitGitGadget
2020-03-25 17:23     ` Junio C Hamano
2020-03-26 13:45       ` Johannes Schindelin
2020-03-26  8:49     ` Jeff King
2020-03-26 14:34       ` Johannes Schindelin
2020-03-25  5:41   ` [PATCH v2 5/5] tests: increase the verbosity of the GPG-related prereqs Johannes Schindelin via GitGitGadget
2020-03-26  8:50     ` Jeff King
2020-03-26 14:36       ` Johannes Schindelin
2020-03-26 15:35   ` [PATCH v3 0/5] Enable GPG in the Windows part of the CI/PR builds Johannes Schindelin via GitGitGadget
2020-03-26 15:35     ` [PATCH v3 1/5] tests(gpg): allow the gpg-agent to start on Windows Johannes Schindelin via GitGitGadget
2020-03-26 15:35     ` [PATCH v3 2/5] t/lib-gpg.sh: stop pretending to be a stand-alone script Johannes Schindelin via GitGitGadget
2020-03-26 15:35     ` [PATCH v3 3/5] tests: do not let lazy prereqs inside `test_expect_*` turn off tracing Johannes Schindelin via GitGitGadget
2020-03-26 15:35     ` [PATCH v3 4/5] tests: turn GPG, GPGSM and RFC1991 into lazy prereqs Johannes Schindelin via GitGitGadget
2020-03-26 15:35     ` [PATCH v3 5/5] tests: increase the verbosity of the GPG-related prereqs Johannes Schindelin via GitGitGadget
2020-03-27  9:12     ` [PATCH v3 0/5] Enable GPG in the Windows part of the CI/PR builds Jeff King
2020-03-27 17:45       ` Junio C Hamano

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