bug#22945: Surprising behaviour (bug?) of zgrep in combination with the -f option and process substitutions

[Paul Eggert]

On 03/15/2016 07:34 PM, Jim Meyering wrote:
> Thank you for the report.
> To summarize, with zgrep-1.6, this erroneously prints matches only
> from the first file:
>
>    $ zgrep -f <(echo .) <(echo a) <(echo b)
>    /dev/fd/12:a
>
> However, with the latest from git (and soon to be gzip-1.7), this now
> works as desired:
>
>    $ zgrep -f <(echo .) <(echo a) <(echo b)
>    /dev/fd/12:a
>    /dev/fd/13:b
>
> I see there is no NEWS entry for this fix and haven't yet identified
> the origin of the bug or the commit that fixed it, but will do so.

Draft gzip 1.7 doesn't work for me (Fedora 23 x86-64). I have worked on 
a patch but don't have a reliable fix yet, or even a portable test case 
to illustrate the bug. Perhaps we should just think of it as a known bug 
for now.