Fix dynamic options changing bug.

ChangeLog

@@ -141,6 +141,13 @@ Now, when Unicode support is compiled, PCRE2_EXTENDED also discards U+0085,
 U+200E, U+200F, U+2028, and U+2029, which are additional characters defined by
 Unicode as "Pattern White Space". This makes PCRE2 compatible with Perl.
 
+32. In certain circumstances, option settings within patterns were not being 
+correctly processed. For example, the pattern /((?i)A)(?m)B/ incorrectly 
+matched "ab". (The (?m) setting lost the fact that (?i) should be reset at the 
+end of its group during the parse process, but without another setting such as 
+(?m) the compile phase got it right.) This bug was introduced by the
+refactoring in release 10.23.
+      
 
 Version 10.31 12-February-2018
 ------------------------------

src/pcre2_compile.c

@@ -2284,11 +2284,14 @@ typedef struct nest_save {
 #define NSF_RESET          0x0001u
 #define NSF_CONDASSERT     0x0002u
 
-/* Of the options that are changeable within the pattern, these are tracked
-during parsing. The rest are used from META_OPTIONS items when compiling. */
+/* Options that are changeable within the pattern must be tracked during
+parsing. Some (e.g. PCRE2_EXTENDED) are implemented entirely during parsing,
+but all must be tracked so that META_OPTIONS items set the correct values for
+the main compiling phase. */
 
-#define PARSE_TRACKED_OPTIONS \
-  (PCRE2_DUPNAMES|PCRE2_EXTENDED|PCRE2_EXTENDED_MORE|PCRE2_NO_AUTO_CAPTURE)
+#define PARSE_TRACKED_OPTIONS (PCRE2_CASELESS|PCRE2_DOTALL|PCRE2_DUPNAMES| \
+  PCRE2_EXTENDED|PCRE2_EXTENDED_MORE|PCRE2_MULTILINE|PCRE2_NO_AUTO_CAPTURE| \
+  PCRE2_UNGREEDY)
 
 /* States used for analyzing ranges in character classes. The two OK values
 must be last. */
@@ -3590,6 +3593,8 @@ while (ptr < ptrend)
       else
         {
         BOOL hyphenok = TRUE;
+        uint32_t oldoptions = options; 
+         
         top_nest->reset_group = 0;
         top_nest->max_group = 0;
         set = unset = 0;
@@ -3677,10 +3682,9 @@ while (ptr < ptrend)
           }
         else *parsed_pattern++ = META_NOCAPTURE;
 
-        /* If nothing changed, no need to record. The check of hyphenok catches 
-        the (?^) case. */
+        /* If nothing changed, no need to record. */
 
-        if (set != 0 || unset != 0 || !hyphenok)
+        if (options != oldoptions)
           {
           *parsed_pattern++ = META_OPTIONS;
           *parsed_pattern++ = options;

testdata/testinput1

@@ -2184,6 +2184,11 @@
     Blah blah      
     blaH blah 
 
+/((?i)blah)\s+(?m)A(?i:\1)/
+    blah ABLAH
+\= Expect no match
+    blah aBLAH
+
 /(?>a*)*/
     a
     aa

testdata/testoutput1

@@ -3346,6 +3346,14 @@ No match
  0: blaH blah
  1: blaH
 
+/((?i)blah)\s+(?m)A(?i:\1)/
+    blah ABLAH
+ 0: blah ABLAH
+ 1: blah
+\= Expect no match
+    blah aBLAH
+No match
+
 /(?>a*)*/
     a
  0: a