Fix bad compilation of a possessively repeated conditional that could match an

empty string.

ChangeLog

@@ -40,6 +40,9 @@ has been tightened up.
 10. The quantifier {1} can be ignored, whether greedy, non-greedy, or 
 possessive. This is a very minor optimization.
 
+11. A possessively repeated conditional group that could match an empty string,
+for example, /(?(R))*+/, was incorrectly compiled.
+
 
 Version 10.20 30-June-2015
 --------------------------

src/pcre2_compile.c

@@ -5269,7 +5269,7 @@ for (;; ptr++)
       conditional, we convert the BRA code to the POS form, and the KET code to
       KETRPOS. (It turns out to be convenient at runtime to detect this kind of
       subpattern at both the start and at the end.) The use of special opcodes
-      makes it possible to reduce greatly the stack usage in pcre_exec(). If
+      makes it possible to reduce greatly the stack usage in pcre2_match(). If
       the group is preceded by OP_BRAZERO, convert this to OP_BRAPOSZERO.
 
       Then, if the minimum number of matches is 1 or 0, cancel the possessive
@@ -5333,7 +5333,7 @@ for (;; ptr++)
               memmove(bracode + 1 + LINK_SIZE, bracode, CU2BYTES(nlen));
               code += 1 + LINK_SIZE;
               nlen += 1 + LINK_SIZE;
-              *bracode = OP_BRAPOS;
+              *bracode = (*bracode == OP_COND)? OP_BRAPOS : OP_SBRAPOS;
               *code++ = OP_KETRPOS;
               PUTINC(code, 0, nlen);
               PUT(bracode, 1, nlen);

testdata/testinput2

@@ -4339,4 +4339,6 @@ a random value. /Ix
 
 /(?C$)$)(?<]/
 
+/(?(R))*+/B
+
 # End of testinput2 

testdata/testoutput2

@@ -14499,4 +14499,17 @@ Failed: error 124 at offset 10: unrecognized character after (?<
 /(?C$)$)(?<]/
 Failed: error 124 at offset 10: unrecognized character after (?<
 
+/(?(R))*+/B
+------------------------------------------------------------------
+        Bra
+        Braposzero
+        SBraPos
+        SCond
+        Cond recurse any
+        Ket
+        KetRpos
+        Ket
+        End
+------------------------------------------------------------------
+
 # End of testinput2