user32: Return empty string from LoadStringW() if resource is not found.

dlls/user32/resource.c

@@ -161,12 +161,13 @@ INT WINAPI DECLSPEC_HOTPATCH LoadStringW( HINSTANCE instance, UINT resource_id,
     if(buffer == NULL)
         return 0;
 
-    /* Use loword (incremented by 1) as resourceid */
-    hrsrc = FindResourceW( instance, MAKEINTRESOURCEW((LOWORD(resource_id) >> 4) + 1),
-                           (LPWSTR)RT_STRING );
-    if (!hrsrc) return 0;
-    hmem = LoadResource( instance, hrsrc );
-    if (!hmem) return 0;
+    if (!(hrsrc = FindResourceW( instance, MAKEINTRESOURCEW((LOWORD(resource_id) >> 4) + 1), (LPWSTR)RT_STRING )) ||
+        !(hmem = LoadResource( instance, hrsrc )))
+    {
+        TRACE( "Failed to load string.\n" );
+        if (buflen > 0) buffer[0] = 0;
+        return 0;
+    }
 
     p = LockResource(hmem);
     string_num = resource_id & 0x000f;

dlls/user32/tests/resource.c

@@ -120,6 +120,33 @@ static void test_LoadStringW(void)
             winetest_pop_context();
         }
     }
+
+    /* Test missing resource. */
+    SetLastError(0xdeadbeef);
+    memset(returnedstringw, 0xcc, sizeof(returnedstringw));
+    length1 = LoadStringW(hInst, 0xdeadbeef, returnedstringw, ARRAY_SIZE(returnedstringw));
+    ok(!length1, "got %d.\n", length1);
+    ok(GetLastError() == ERROR_RESOURCE_NAME_NOT_FOUND || broken(GetLastError() == ERROR_MUI_FILE_NOT_FOUND) /* Win7 */,
+            "got %lu.\n", GetLastError());
+    ok(!returnedstringw[0], "got %#x.\n", returnedstringw[0]);
+    ok(returnedstringw[1] == 0xcccc, "got %#x.\n", returnedstringw[1]);
+
+    SetLastError(0xdeadbeef);
+    memset(returnedstringw, 0xcc, sizeof(returnedstringw));
+    length1 = LoadStringW(hInst, 0xdeadbeef, returnedstringw, 0);
+    ok(!length1, "got %d.\n", length1);
+    ok(GetLastError() == ERROR_RESOURCE_NAME_NOT_FOUND || broken(GetLastError() == ERROR_MUI_FILE_NOT_LOADED) /* Win7 */,
+            "got %lu.\n", GetLastError());
+    ok(returnedstringw[0] == 0xcccc, "got %#x.\n", returnedstringw[1]);
+
+    SetLastError(0xdeadbeef);
+    memset(returnedstringw, 0xcc, sizeof(returnedstringw));
+    length1 = LoadStringW(hInst, 0xdeadbeef, returnedstringw, 1);
+    ok(!length1, "got %d.\n", length1);
+    ok(GetLastError() == ERROR_RESOURCE_NAME_NOT_FOUND || broken(GetLastError() == ERROR_MUI_FILE_NOT_LOADED) /* Win7 */,
+            "got %lu.\n", GetLastError());
+    ok(!returnedstringw[0], "got %#x.\n", returnedstringw[0]);
+    ok(returnedstringw[1] == 0xcccc, "got %#x.\n", returnedstringw[1]);
 }
 
 static void test_LoadStringA (void)