Bug 854124 - Update RegExpStatics on empty match in str_replace_regexp_remove(). r=dvander

js/src/jit-test/tests/basic/bug854124.js

@@ -0,0 +1,8 @@
+// Don't assert.
+"p".match(/(p)/);
+assertEq(RegExp.$1, "p");
+assertEq(RegExp.$2, "");
+
+"x\ny\n".replace(/(^\n*)/, "");
+assertEq(RegExp.$1, "");
+assertEq(RegExp.$2, "");

js/src/jsstr.cpp

@@ -2465,16 +2465,18 @@ str_replace_regexp_remove(JSContext *cx, CallArgs args, HandleString str, RegExp
         lazyIndex = lastIndex;
         lastIndex = startIndex;
 
+        if (match.isEmpty())
+            startIndex++;
+
         /* Non-global removal executes at most once. */
         if (!re.global())
             break;
-
-        if (match.isEmpty())
-            startIndex++;
     }
 
     /* If unmatched, return the input string. */
     if (!lastIndex) {
+        if (startIndex > 0)
+            cx->regExpStatics()->updateLazily(cx, stableStr, &re, lazyIndex);
         args.rval().setString(str);
         return true;
     }