Fix repeated condition check by duplicated name bug.

ChangeLog

@@ -111,6 +111,10 @@ incorrect code to be compiled when recursive forward references were involved.
 For example, in this pattern: /(?1)()((((((\1++))\x85)+)|))/. This bug was
 discovered by the LLVM fuzzer.
 
+28. A repeated conditional group whose condition was a reference by name caused
+a buffer overflow if there was more than one group with the given name. This
+bug was discovered by the LLVM fuzzer.
+
 
 Version 10.10 06-March-2015
 ---------------------------

src/pcre2_compile.c

@@ -5425,7 +5425,8 @@ for (;; ptr++)
         the referenced name is one of a number of duplicates, a different
         opcode is used and it needs more memory. Unfortunately we cannot tell
         whether this is the case in the first pass, so we have to allow for
-        more memory always. */
+        more memory always. In the second pass, the additional to skipunits
+        happens later. */
 
         else
           {
@@ -5445,7 +5446,7 @@ for (;; ptr++)
             ptr++;
             }
           namelen = (int)(ptr - name);
-          if (lengthptr != NULL) *lengthptr += IMM2_SIZE;
+          if (lengthptr != NULL) skipunits += IMM2_SIZE;
           }
 
         /* Check the terminator */
@@ -8010,8 +8011,6 @@ if (cb.names_found > 0)
 error, errorcode will be set non-zero, so we don't need to look at the result
 of the function here. */
 
-/* fprintf(stderr, "+++\n\nPASS TWO\n"); */
-
 ptr = pattern + skipatstart;
 code = (PCRE2_UCHAR *)codestart;
 *code = OP_BRA;
@@ -8068,9 +8067,6 @@ if (cb.hwm > cb.start_workspace)
     cb.hwm -= LINK_SIZE;
     offset = GET(cb.hwm, 0);
     recno = GET(codestart, offset);
-
-/* fprintf(stderr, "+++offset=%d recno=%d\n", offset, recno); */
-
     if (recno != prev_recno)
       {
       groupptr = PRIV(find_bracket)(codestart, utf, recno);

testdata/testinput2

@@ -4298,4 +4298,12 @@ a random value. /Ix
 
 /\V\x85\9*+((?2)\3++()2)*:2/
 
+/(((?(R)){0,2}) (?''((?'R')((?'R')))))/dupnames
+
+/(((?(X)){0,2}) (?''((?'X')((?'X')))))/dupnames
+
+/(((?(R)){0,2}) (?''((?'X')((?'R')))))/
+
+/$(&.+[\p{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(?(R)){0,6}?|){12\x8a\X*?\x8a\x0b\xd1^9\3*+(\xc1,\k'P'\xb4)\xcc(z\z(?JJ)(?''8};(\x0b\xd1^9\?'3*+(\xc1.]k+\x0b'Pm'\xb4\xcc4'\xd1'(?''))?-%--\x95$9*\4'|\xd1(''%\x95*$9)#(?'R')3\x07?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+!~:(?)''(d'E:yD!\s(?'R'\x1e;\x10:U))|')g!\xb0*){29+))#(?'P'})*?/
+
 # End of testinput2 

testdata/testoutput2

@@ -14397,4 +14397,12 @@ Failed: error 115 at offset 22: reference to non-existent subpattern
 /\V\x85\9*+((?2)\3++()2)*:2/
 Failed: error 115 at offset 26: reference to non-existent subpattern
 
+/(((?(R)){0,2}) (?''((?'R')((?'R')))))/dupnames
+
+/(((?(X)){0,2}) (?''((?'X')((?'X')))))/dupnames
+
+/(((?(R)){0,2}) (?''((?'X')((?'R')))))/
+
+/$(&.+[\p{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(?(R)){0,6}?|){12\x8a\X*?\x8a\x0b\xd1^9\3*+(\xc1,\k'P'\xb4)\xcc(z\z(?JJ)(?''8};(\x0b\xd1^9\?'3*+(\xc1.]k+\x0b'Pm'\xb4\xcc4'\xd1'(?''))?-%--\x95$9*\4'|\xd1(''%\x95*$9)#(?'R')3\x07?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+!~:(?)''(d'E:yD!\s(?'R'\x1e;\x10:U))|')g!\xb0*){29+))#(?'P'})*?/
+
 # End of testinput2