Re: [PATCH] Don't try to reclose in command_close_bidi_pipe

[Yuval Kogman <nothingmuch@woobling.org>]

Resending, forgot to CC

2009/1/30 Tay Ray Chuan <rctay89@gmail.com>
> From this message, you seem to intend this as a fix. Can you tell us
> how one might go about to reproduce this issue?

Here is an example:
http://github.com/yanick/git-cpan-patch/blob/ed67d3f86f371764935fd0da3e7f08536c95b606/git-cpan-import#L190

Since git-commit-tree requires the message to be written before it can
write the sha1 of the new commit object, the handle has to be closed
already, which makes command_close_bidi_pipe die with an error.
The workaround in the linked code reopens a fake handle so that
close() will not error.
For what it's worth, I've been poking at t/t9700/test.pl but since
it's pretty sparse I figured I should contribute this fix
independently.

> Is "unless defined(fileno($fh))" a reliable way to check if the handle
> is closed?

Yes, since the handle is expected to be the result of a pipe open. The
documentation refers to this case:

    open my $fh, "<", \$buffer;

in which case the filehandle $fh has no associated file descriptor.

fileno() is not a universal check, but it is applicable in this situation.