From 63cab0dba95b9a03e392dcd70017ca792f0c8d3a Mon Sep 17 00:00:00 2001
From: "Philip.Hazel" <Philip.Hazel@gmail.com>
Date: Sun, 29 Mar 2015 15:40:45 +0000
Subject: [PATCH] Fix non-diagnosis of syntax error for (?(?< when not followed
 by ! or =.

---
 ChangeLog            | 5 +++++
 src/pcre2_compile.c  | 4 +++-
 testdata/testinput2  | 4 ++++
 testdata/testoutput2 | 7 ++++++-
 4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7a4c838..619029f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -45,6 +45,11 @@ discovered by the LLVM fuzzer.
 between a subroutine call and its quantifier was incorrectly compiled, leading
 to buffer overflow or other errors. This bug was discovered by the LLVM fuzzer.
 
+12. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an 
+assertion after (?(. The code was failing to check the character after (?(?< 
+for the ! or = that would indicate a lookbehind assertion. This bug was
+discovered by the LLVM fuzzer.
+
 
 Version 10.10 06-March-2015
 ---------------------------
diff --git a/src/pcre2_compile.c b/src/pcre2_compile.c
index 92c204d..b349900 100644
--- a/src/pcre2_compile.c
+++ b/src/pcre2_compile.c
@@ -5272,7 +5272,9 @@ for (;; ptr++)
         if (tempptr[1] == CHAR_QUESTION_MARK &&
               (tempptr[2] == CHAR_EQUALS_SIGN ||
                tempptr[2] == CHAR_EXCLAMATION_MARK ||
-               tempptr[2] == CHAR_LESS_THAN_SIGN))
+                 (tempptr[2] == CHAR_LESS_THAN_SIGN &&
+                   (tempptr[3] == CHAR_EQUALS_SIGN ||
+                    tempptr[3] == CHAR_EXCLAMATION_MARK))))  
           {
           cb->iscondassert = TRUE;
           break;
diff --git a/testdata/testinput2 b/testdata/testinput2
index 2acfcca..5c26c1f 100644
--- a/testdata/testinput2
+++ b/testdata/testinput2
@@ -4241,4 +4241,8 @@ a random value. /Ix
 "(*NO_JIT)((?2)+)((?1)){"
     abcd{
 
+# Perl fails to diagnose the absence of an assertion
+
+"(?(?<E>.*!.*)?)"
+
 # End of testinput2 
diff --git a/testdata/testoutput2 b/testdata/testoutput2
index 65e7605..1c6829f 100644
--- a/testdata/testoutput2
+++ b/testdata/testoutput2
@@ -573,7 +573,7 @@ Failed: error 128 at offset 3: assertion expected after (?( or (?(?C)
 Failed: error 115 at offset 7: reference to non-existent subpattern
 
 /(?(?<ab))/
-Failed: error 142 at offset 7: syntax error in subpattern name (missing terminator)
+Failed: error 128 at offset 3: assertion expected after (?( or (?(?C)
 
 /((?s)blah)\s+\1/I
 Capturing subpattern count = 1
@@ -14204,4 +14204,9 @@ No match
     abcd{
 Failed: error -52: nested recursion at the same subject position
 
+# Perl fails to diagnose the absence of an assertion
+
+"(?(?<E>.*!.*)?)"
+Failed: error 128 at offset 3: assertion expected after (?( or (?(?C)
+
 # End of testinput2