Re: Is t7006-pager.sh racy?

On Sun, Nov 21 2021, Jeff King wrote:

On Sun, Oct 24, 2021 at 07:03:49PM +0200, SZEDER Gábor wrote:

quoted

quoted

What makes us expect that the "git log" invocation should trigger a
SIGPIPE in the first place?

A misunderstanding, perhaps, because those 'git log' commands with
their early-exiting pagers rarely trigger SIGPIPE.

I happened to be looking in this area today[1], and I think it turns out
not to be "rarely", but rather "never" for some of the tests.

The test in question sets the pager to "does-not-exist". But in that
case we will realize immediately via run-command.c that we could not run
the pager, and will not even redirect our stdout to it.

For example, doing this:

  GIT_PAGER=does-not-exist git -c alias.foo='!yes' -p foo

will never get SIGPIPE; it will just write infinitely to the original
stdout, and return success.

Whereas this:

  GIT_PAGER=false git -c alias.foo='!yes' -p foo

will reliably get SIGPIPE. But even if we used it (with a while loop to
instead of "yes" address the portability concern), the tests in t7006
would still be wrong, because they are sending test-terminal's output to
a closed pipe (so we'd still see SIGPIPE regardless of Git's behavior).
They should be sending test_terminal's output to a file or /dev/null.

It seems like this thread stalled. Ævar, were you planning to fix these
tests?

Not at this point I'm not! :)

Anyway, a belated thanks for tackling this issue & sorry about the
mess. I see jk/t7006-sigpipe-tests-fix is marked already & those fixes
LGTM. This fell through the cracks for me among other E-Mail traffic.

[...]