util._matcher: speed up regexp matching.
In 4babaa52badf, Benoit made a change that substantially slows matching
when a big .hgignore file is in play, because it calls into the regexp
matching engine potentially hundreds of times per file to be matched.
I've partly rolled back his change, so that we only call into the matcher
once per file, but preserved the ability to report a meaningful error
message if there's a syntax error in the regexp.
#!/bin/sh
hg init
echo foo > foo
hg add foo
hg commit -m1 -d"0 0"
echo "# should show copy"
hg copy foo bar
hg debugstate|grep '^copy'
echo "# shouldn't show copy"
hg commit -m2 -d"0 0"
hg debugstate|grep '^copy'
echo "# should match"
hg debugindex .hg/store/data/foo.i
hg debugrename bar
echo bleah > foo
echo quux > bar
hg commit -m3 -d"0 0"
echo "# should not be renamed"
hg debugrename bar
hg copy -f foo bar
echo "# should show copy"
hg debugstate|grep '^copy'
hg commit -m3 -d"0 0"
echo "# should show no parents for tip"
hg debugindex .hg/store/data/bar.i
echo "# should match"
hg debugindex .hg/store/data/foo.i
hg debugrename bar
echo "# should show no copies"
hg debugstate|grep '^copy'
exit 0