Revision: 1739
http://vcs.pcre.org/viewvc?view=rev&revision=1739
Author: ph10
Date: 2018-09-02 18:05:38 +0100 (Sun, 02 Sep 2018)
Log Message:
-----------
Fix anchoring bug in conditional subexpression.
Modified Paths:
--------------
code/trunk/ChangeLog
code/trunk/pcre_compile.c
code/trunk/testdata/testinput2
code/trunk/testdata/testoutput2
Modified: code/trunk/ChangeLog
===================================================================
--- code/trunk/ChangeLog 2018-08-17 14:50:21 UTC (rev 1738)
+++ code/trunk/ChangeLog 2018-09-02 17:05:38 UTC (rev 1739)
@@ -32,7 +32,12 @@
with only characters less than 0x100, the first class was incorrectly being
auto-possessified, causing incorrect match failures.
+6. If the only branch in a conditional subpattern was anchored, the whole
+subpattern was treated as anchored, when it should not have been, since the
+assumed empty second branch cannot be anchored. Demonstrated by test patterns
+such as /(?(1)^())b/ or /(?(?=^))b/.
+
Version 8.42 20-March-2018
--------------------------
Modified: code/trunk/pcre_compile.c
===================================================================
--- code/trunk/pcre_compile.c 2018-08-17 14:50:21 UTC (rev 1738)
+++ code/trunk/pcre_compile.c 2018-09-02 17:05:38 UTC (rev 1739)
@@ -8682,13 +8682,21 @@
if (!is_anchored(scode, new_map, cd, atomcount)) return FALSE;
}
- /* Positive forward assertions and conditions */
+ /* Positive forward assertion */
- else if (op == OP_ASSERT || op == OP_COND)
+ else if (op == OP_ASSERT)
{
if (!is_anchored(scode, bracket_map, cd, atomcount)) return FALSE;
}
+ /* Condition; not anchored if no second branch */
+
+ else if (op == OP_COND)
+ {
+ if (scode[GET(scode,1)] != OP_ALT) return FALSE;
+ if (!is_anchored(scode, bracket_map, cd, atomcount)) return FALSE;
+ }
+
/* Atomic groups */
else if (op == OP_ONCE || op == OP_ONCE_NC)
Modified: code/trunk/testdata/testinput2
===================================================================
--- code/trunk/testdata/testinput2 2018-08-17 14:50:21 UTC (rev 1738)
+++ code/trunk/testdata/testinput2 2018-09-02 17:05:38 UTC (rev 1739)
@@ -4257,4 +4257,7 @@
ab
aaab
+/(?(?=^))b/
+ abc
+
/-- End of testinput2 --/
Modified: code/trunk/testdata/testoutput2
===================================================================
--- code/trunk/testdata/testoutput2 2018-08-17 14:50:21 UTC (rev 1738)
+++ code/trunk/testdata/testoutput2 2018-09-02 17:05:38 UTC (rev 1739)
@@ -14721,4 +14721,8 @@
0: ab
1: a
+/(?(?=^))b/
+ abc
+ 0: b
+
/-- End of testinput2 --/
