Re: git fails with a broken pipe when one quits the pager

On 2021-01-31 02:47:59 +0100, Ævar Arnfjörð Bjarmason wrote:

On Fri, Jan 15 2021, Vincent Lefevre wrote:

quoted

I had reported the following bug at
  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914896

It still occurs with Git 2.30.0.

Some git commands with a lot of output fail with a broken pipe when
one quits the pager (without going to the end of the output).

For instance, in zsh:

cventin% setopt PRINT_EXIT_VALUE
cventin% git log
zsh: broken pipe  git log
cventin% echo $?
141
cventin% 

This is annoying[...]

Yes it's annoying, but the annoying output is from zsh, not
git. Consider a smarter implementation like:

    case $__exit_status in
        0) __exit_emoji=😀;;
        1) __exit_emoji=☹️ ;;
        141) __exit_emoji=🤕 ;;
        [...]

Then put the $__exit_emoji in your $PS1 prompt, now when you 'q' in a
pager you know the difference between having quit at the full output
being emitted or not.

FYI, I already have the exit status already in my prompt (the above
commands were just for the example). Still, the git behavior is
disturbing.

Moreover, this doesn't solve the issue when doing something like

  git log && some_other_command

quoted

And of course, I don't want to hide error messages by default, because
this would hide *real* errors.

Isn't the solution to this that your shell stops reporting failures due
to SIGPIPE in such a prominent way then?

No! I want to be warned about real SIGPIPEs.

quoted

The broken pipe is internally expected, thus should not be reported
by git.

Just to be clear: this broken pipe should be discarded only when git
uses its builtin pager feature, not with a general pipe, where the
error may be important.

For instance,

$ { git log ; echo "Exit status: $?" >&2 ; } | true

should still output

Exit status: 141

I don't get it, how is it less meaningful when git itself invokes the
pager?

I don't understand your question. If I invoke the pager myself,
I don't get a SIGPIPE:

cventin:~/software/gcc-trunk> git log
cventin:~/software/gcc-trunk[PIPE]> git log|m
cventin:~/software/gcc-trunk>

-- 
Vincent Lefèvre [off-list ref] - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)