From: Nicholas Clark <nick@ccl4.org>
Date: Sun, 10 Dec 2006 22:31:56 +0000 (+0000)
Subject: Downgrading a fixed or floating substring of a pattern whilst matching
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=0b3e77ec2e46a23afe97475f6b9bf7880fae85f1;p=p5sagit%2Fp5-mst-13.2.git

Downgrading a fixed or floating substring of a pattern whilst matching
a studied string seems to get to a "should not happen" [bug #41067]
It seems that Perl_regexec_flags() assumes that if the pre-downgraded
substring is FBM compiled, then the downgraded version will be too,
hence changing the downgrade and upgrade routines to FBM compile seems
to be a correct fix.

p4raw-id: //depot/perl@29502
---

diff --git a/regexec.c b/regexec.c
index 2da8bfd..7cd7d5f 100644
--- a/regexec.c
+++ b/regexec.c
@@ -5621,6 +5621,8 @@ S_to_utf8_substr(pTHX_ register regexp *prog)
 	SV* const sv = newSVsv(prog->float_substr);
 	prog->float_utf8 = sv;
 	sv_utf8_upgrade(sv);
+	if (SvVALID(prog->float_substr))
+	    fbm_compile(sv, 0);
 	if (SvTAIL(prog->float_substr))
 	    SvTAIL_on(sv);
 	if (prog->float_substr == prog->check_substr)
@@ -5630,6 +5632,8 @@ S_to_utf8_substr(pTHX_ register regexp *prog)
 	SV* const sv = newSVsv(prog->anchored_substr);
 	prog->anchored_utf8 = sv;
 	sv_utf8_upgrade(sv);
+	if (SvVALID(prog->anchored_substr))
+	    fbm_compile(sv, 0);
 	if (SvTAIL(prog->anchored_substr))
 	    SvTAIL_on(sv);
 	if (prog->anchored_substr == prog->check_substr)
@@ -5645,6 +5649,8 @@ S_to_byte_substr(pTHX_ register regexp *prog)
 	SV* sv = newSVsv(prog->float_utf8);
 	prog->float_substr = sv;
 	if (sv_utf8_downgrade(sv, TRUE)) {
+	    if (SvVALID(prog->float_utf8))
+		fbm_compile(sv, 0);
 	    if (SvTAIL(prog->float_utf8))
 		SvTAIL_on(sv);
 	} else {
@@ -5658,6 +5664,8 @@ S_to_byte_substr(pTHX_ register regexp *prog)
 	SV* sv = newSVsv(prog->anchored_utf8);
 	prog->anchored_substr = sv;
 	if (sv_utf8_downgrade(sv, TRUE)) {
+	    if (SvVALID(prog->anchored_utf8))
+		fbm_compile(sv, 0);
 	    if (SvTAIL(prog->anchored_utf8))
 		SvTAIL_on(sv);
 	} else {
diff --git a/t/op/re_tests b/t/op/re_tests
index d0f6ae3..48dbb79 100644
--- a/t/op/re_tests
+++ b/t/op/re_tests
@@ -1013,6 +1013,7 @@ X(?<=foo.)[YZ]	..XfooXY..	y	pos	8
 ^(??{q(.+)})\x{100}	\x{100}\x{100}	y	$&	\x{100}\x{100}
 ^(??{q(.)})\x{100}	\x{100}\x{100}	y	$&	\x{100}\x{100}
 ^(??{chr 0x100})\xbb	\x{100}\x{bb}	y	$&	\x{100}\x{bb}
+\x{100}?(??{""})xxx	xxx	y	$&	xxx
 ^(.)(??{"(.)(.)"})(.)$	abcd	y	$1-$2	a-d
 ^(.)(??{"(bz+|.)(.)"})(.)$	abcd	y	$1-$2	a-d
 ^(.)((??{"(.)(cz+)"})|.)	abcd	y	$1-$2	a-b