From: Gurusamy Sarathy <gsar@cpan.org>
Date: Sat, 19 Feb 2000 17:33:59 +0000 (+0000)
Subject: fix bug in backtracking optimizer (from Makoto Ishisone
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=1aeab75ab913b2442f1de7300d375422255ad122;p=p5sagit%2Fp5-mst-13.2.git

fix bug in backtracking optimizer (from Makoto Ishisone
<ishisone@sra.co.jp>)

p4raw-id: //depot/perl@5151
---

diff --git a/regexec.c b/regexec.c
index e63fa6f..f9f2cc0 100644
--- a/regexec.c
+++ b/regexec.c
@@ -3045,8 +3045,14 @@ S_regmatch(pTHX_ regnode *prog)
 		n = regrepeat(scan, n);
 		locinput = PL_reginput;
 		if (ln < n && PL_regkind[(U8)OP(next)] == EOL &&
-		    (!PL_multiline  || OP(next) == SEOL))
+		    (!PL_multiline  || OP(next) == SEOL || OP(next) == EOS)) {
 		    ln = n;			/* why back off? */
+		    /* ...because $ and \Z can match before *and* after
+		       newline at the end.  Consider "\n\n" =~ /\n+\Z\n/.
+		       We should back off by one in this case. */
+		    if (UCHARAT(PL_reginput - 1) == '\n' && OP(next) != EOS)
+			ln--;
+		}
 		REGCP_SET;
 		if (paren) {
 		    while (n >= ln) {
diff --git a/t/op/pat.t b/t/op/pat.t
index 439796d..142b82e 100755
--- a/t/op/pat.t
+++ b/t/op/pat.t
@@ -4,7 +4,7 @@
 # the format supported by op/regexp.t.  If you want to add a test
 # that does fit that format, add it to op/re_tests, not here.
 
-print "1..207\n";
+print "1..210\n";
 
 BEGIN {
     chdir 't' if -d 't';
@@ -978,3 +978,16 @@ $test++;
 print "not " if "@b" ne "@c";
 print "ok $test\n";
 $test++;
+
+# see if backtracking optimization works correctly
+"\n\n" =~ /\n  $ \n/x or print "not ";
+print "ok $test\n";
+$test++;
+
+"\n\n" =~ /\n* $ \n/x or print "not ";
+print "ok $test\n";
+$test++;
+
+"\n\n" =~ /\n+ $ \n/x or print "not ";
+print "ok $test\n";
+$test++;