bug#32093: 27.0.50; M-x grep appends /dev/null to command line

[Noam Postavsky]

On 10 July 2018 at 11:55, Eli Zaretskii <eliz@gnu.org> wrote:

> But that was just a suggestion.  I see Paul decided to continue using
> etc/HELLO, just with a different search patterns.  If we are OK with
> that, we can put that issue to rest.

Yeah, I don't think it really matters whether we search etc/HELLO or README.

> We could even take one more step back and ask ourselves why do we need
> this particular test.  I believe it's because we want to support file
> names with embedded newlines, in which case perhaps such niche use
> cases could be supported by a special command or a special user
> option?

I don't think it's about newlines in filenames (in fact,
grep-regexp-alist doesn't support that regardless).  As far as I can
tell, the HELLO test is checking whether we can pass -H to get the
filename together with the matches, or if we need to pass multiple files
to do that.

To do without -H, we would need to handle matches in both formats which
would make the matching regexp more complicated, and we would need to be
able to extract the filename from the shell command that the user types
in.  That would be quite difficult to do correctly in general.