From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: Duy Nguyen <pclouds@gmail.com>, Johannes Sixt <j6t@kdbg.org>,
Git Mailing List <git@vger.kernel.org>,
Stefan Beller <sbeller@google.com>,
Anthony Sottile <asottile@umich.edu>
Subject: Re: [PATCH v2 0/3] nd/clear-gitenv-upon-use-of-alias
Date: Tue, 29 Dec 2015 13:34:41 -0800 [thread overview]
Message-ID: <xmqqlh8dgcr2.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20151229081222.GB9254@sigill.intra.peff.net> (Jeff King's message of "Tue, 29 Dec 2015 03:12:22 -0500")
Jeff King <peff@peff.net> writes:
> The outer git wrapper doesn't start the pager, so its stderr still gets
> seen by the user. But the _inner_ git-log does start the pager, and then
> dies of SIGPIPE.
>
> So yeah, I think we want something like this on top of
> nd/clear-gitenv-upon-use-of-alias.
That makes sense to me.
> -- >8 --
> Subject: [PATCH] run-command: don't warn on SIGPIPE deaths
>
> When git executes a sub-command, we print a warning if the
> command dies due to a signal, but make an exception for
> "uninteresting" cases like SIGINT and SIGQUIT (since the
> user presumably just hit ^C).
>
> We should make a similar exception for SIGPIPE, because it's
> an expected and uninteresting return in most cases; it
> generally means the user quit the pager before git had
> finished generating all output. This used to be very hard
> to trigger in practice, because:
>
> 1. We only complain if we see a real SIGPIPE death, not
> the shell-induced 141 exit code. This means that
> anything we run via the shell does not trigger the
> warning, which includes most non-trivial aliases.
>
> 2. The common case for SIGPIPE is the user quitting the
> pager before git has finished generating all output.
> But if the user triggers a pager with "-p", we redirect
> the git wrapper's stderr to that pager, too. Since the
> pager is dead, it means that the message goes nowhere.
>
> 3. You can see it if you run your own pager, like
> "git foo | head". But that only happens if "foo" is a
> non-builtin (so it doesn't work with "log", for
> example).
>
> However, it may become more common after 86d26f2, which
> teaches alias to re-exec builtins rather than running them
> in the same process. This case doesn't trigger (1), as we
> don't need a shell to run a git command. It doesn't trigger
> (2), because the pager is not started by the original git,
> but by the inner re-exec of git. And it doesn't trigger (3),
> because builtins are treated more like non-builtins in this
> case.
>
> Given how flaky this message already is (e.g., you cannot
> even know whether you will see it, as git optimizes out some
> shell invocations behind the scenes based on the contents of
> the command!), and that it is unlikely to ever provide
> useful information, let's suppress it for all cases of
> SIGPIPE.
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
> run-command.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/run-command.c b/run-command.c
> index 13fa452..694a6ff 100644
> --- a/run-command.c
> +++ b/run-command.c
> @@ -245,7 +245,7 @@ static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
> error("waitpid is confused (%s)", argv0);
> } else if (WIFSIGNALED(status)) {
> code = WTERMSIG(status);
> - if (code != SIGINT && code != SIGQUIT)
> + if (code != SIGINT && code != SIGQUIT && code != SIGPIPE)
> error("%s died of signal %d", argv0, code);
> /*
> * This return value is chosen so that code & 0xff
next prev parent reply other threads:[~2015-12-29 21:34 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CA+dzEB=2LJXiLSTqyLw8AeHNwdQicwvEiMg=hVEX0-_s1bySpA@mail.gmail.com>
2015-11-24 2:22 ` Fwd: Git clone fails during pre-commit hook due to GIT_WORK_TREE=. (regression 2.5 -> 2.6) Anthony Sottile
2015-11-24 17:57 ` Stefan Beller
2015-11-25 20:13 ` Duy Nguyen
2015-11-30 19:01 ` Duy Nguyen
2015-11-30 20:16 ` Junio C Hamano
2015-12-01 17:59 ` Duy Nguyen
2015-12-02 17:09 ` Junio C Hamano
2015-12-03 18:17 ` [PATCH 1/2] git.c: make it clear save_env() is for alias handling only Nguyễn Thái Ngọc Duy
2015-12-03 18:17 ` [PATCH 2/2] setup.c: re-fix d95138e (setup: set env $GIT_WORK_TREE when Nguyễn Thái Ngọc Duy
2015-12-04 20:35 ` Junio C Hamano
2015-12-05 5:48 ` Duy Nguyen
2015-12-05 15:32 ` [PATCH 3/2] git.c: make sure we do not leak GIT_* to alias scripts Nguyễn Thái Ngọc Duy
2015-12-07 18:54 ` Junio C Hamano
2015-12-08 16:55 ` Duy Nguyen
2015-12-08 17:20 ` Jeff King
2015-12-08 23:55 ` Junio C Hamano
2015-12-05 19:12 ` [PATCH 2/2] setup.c: re-fix d95138e (setup: set env $GIT_WORK_TREE when Duy Nguyen
2015-12-07 18:33 ` Junio C Hamano
2015-12-20 7:50 ` [PATCH v2 0/3] nd/clear-gitenv-upon-use-of-alias Nguyễn Thái Ngọc Duy
2015-12-20 7:50 ` [PATCH v2 1/3] git.c: make it clear save_env() is for alias handling only Nguyễn Thái Ngọc Duy
2015-12-20 7:50 ` [PATCH v2 2/3] setup.c: re-fix d95138e (setup: set env $GIT_WORK_TREE when Nguyễn Thái Ngọc Duy
2015-12-20 7:50 ` [PATCH v2 3/3] git.c: make sure we do not leak GIT_* to alias scripts Nguyễn Thái Ngọc Duy
2015-12-21 21:18 ` [PATCH v2 0/3] nd/clear-gitenv-upon-use-of-alias Junio C Hamano
2015-12-22 10:57 ` Duy Nguyen
2015-12-22 11:53 ` Duy Nguyen
2015-12-22 18:13 ` Junio C Hamano
2015-12-23 9:37 ` Jeff King
2015-12-23 10:20 ` Duy Nguyen
2015-12-23 16:17 ` Eric Sunshine
2015-12-23 20:37 ` Johannes Sixt
2015-12-23 21:31 ` Jeff King
2015-12-24 9:35 ` Duy Nguyen
2015-12-29 8:12 ` Jeff King
2015-12-29 21:34 ` Junio C Hamano [this message]
2015-12-21 10:22 ` [PATCH] Revert "setup: set env $GIT_WORK_TREE when work tree is set, like $GIT_DIR" Nguyễn Thái Ngọc Duy
2015-12-21 17:28 ` Junio C Hamano
2015-12-21 18:31 ` Junio C Hamano
2015-12-22 1:06 ` Duy Nguyen
2015-12-22 21:50 ` Junio C Hamano
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