Fix unicode in object accesses, eg c["\u00FC"]=42 (fix #2429)

ChangeLog

@@ -25,6 +25,7 @@
             Graphics: wrapString will now wrap lines on comma, dot, dash, and between images
             Graphics: Improve PBF font loading to handle v3, plus Espruino extension to handle >10k glyphs in one file
             Graphics: Graphics.stringMetrics now returns 'unknownChars' to indicate if a font can't render a character in the String
+            Fix unicode in object accesses, eg c["\u00FC"]=42 (fix #2429)
 
      2v19 : Fix Object.values/entries for numeric keys after 2v18 regression (fix #2375)
             nRF52: for SD>5 use static buffers for advertising and scan response data (#2367)

src/jsvar.c

@@ -1287,7 +1287,7 @@ JsVar *jsvMakeIntoVariableName(JsVar *var, JsVar *valueOrZero) {
         JsVar* ext = jsvNewWithFlags(JSV_STRING_EXT_0);
         if (ext) {
           jsvSetCharactersInVar(ext, (size_t)index);
-          jsvSetLastChild(last, jsvGetRef(ext));
+          jsvSetLastChild(last, jsvGetRef(ext));  // no ref for stringext
           jsvUnLock(ext);
         } // TODO else?
       }
@@ -2783,10 +2783,10 @@ JsVar *jsvCopy(JsVar *src, bool copyChildren) {
       } else {
         JsVar *childCopy = jsvCopy(child, true);
         if (childCopy) {// could be out of memory
-          jsvSetLastChild(dstChild, jsvGetRef(childCopy)); // no ref for stringext
+          jsvSetLastChild(dstChild, jsvGetRef(jsvRef(childCopy)));
           jsvUnLock(childCopy);
         }
-        jsvUnLock2(src, dstChild);
+        jsvUnLock3(src, dstChild, child);
         return dst;
       }
     }

tests/test_UTF8_fieldname.js

@@ -0,0 +1,17 @@
+// https://github.com/espruino/Espruino/issues/2429
+// there were already some changes in https://github.com/espruino/Espruino/commit/dde4d3a5ca52782fbe7cefacb18d52d9655b485a
+
+const s = "\u00FC";
+const o = {};
+const o2 = {"\u00FC":42}; // this one was ok after above changes
+
+// 
+print("==================== O2");
+trace(o2); // ok
+print("==================== O");
+o[s] = 42;
+trace(o); // not ok
+
+// o an o2 were different before
+
+result = o["\u00FC"]==42;