Optimize return value of util._matcher for common command line case
This will trigger every time somebody runs something like "hg diff"
or "hg status" without any arguments.
The important part here is returning util.always as the match function,
which is a much simpler (and faster) function than the usual return
value, and allows other code to just skip the filtering if it knows
all files will match.
#!/bin/sh
echo "[extensions]" >> $HGRCPATH
echo "extdiff=" >> $HGRCPATH
hg init a
cd a
echo a > a
hg add
hg extdiff -o -r $opt
echo "[extdiff]" >> $HGRCPATH
echo "cmd.falabala=echo" >> $HGRCPATH
echo "opts.falabala=diffing" >> $HGRCPATH
hg falabala
hg help falabala
hg ci -d '0 0' -mtest1
echo b >> a
hg ci -d '1 0' -mtest2
hg falabala -r 0:1
# test diff during merge
hg update 0
echo b >> b
hg add b
hg ci -m "new branch" -d '1 0'
hg update -C 1
hg merge tip
hg falabala || echo "diff-like tools yield a non-zero exit code"