feature: warn if called in void context

[dolmen]

pushd is so magic that it is easy to forget to call it in scalar context (as the variable is normally not used in the rest of the scope).
It would be a helpful addition to check if pushd/tempd/preserve are called in void context (!defined wantarray) and warn.

[xdg]

Great idea. Want to send a patch? :-)

[dolmen]

Want to send a patch? :-)

Yep.
Ideally the warn would happen only if warnings are enabled in the caller scope. Any idea on how to check that?

[xdg]

Probably with warnings::warn_if() but you'll need to choose a suitable category. From perldiag, the "useless" warnings appear to be in category "misc".

[dolmen]

"Useless use of %s in void context" is in the void category. That's what I'll use.

[dolmen]

Do you have any preference for a module to capture warnings in the testsuite? I can also directly hook $SIG{__WARN__} if you prefer...

[xdg]

Hook $SIG{__WARN__} please.

[xdg]

Fixed by #9