match: allow pats to be None...
match: allow pats to be None
match.match already interprets "!bool(patterns)" as matching
everything (but includes and excludes still apply). We might as well
allow None, which lets us simplify some callers a bit.
I originally wrote this patch while trying to change
match.match(patterns=[]) to mean to match no patterns. This patch is
one step towards that goal. I'm not sure it'll be worth the effort to
go all the way there, but I think this patch still makes sense on its
own.
