fix #448: Do not load monitor dimensions if they're not present

Author: adazem009

src/internal/scratch3reader.cpp

@@ -404,12 +404,16 @@ bool Scratch3Reader::load()
             }
 
             // width
-            READER_STEP(step, "monitor -> width");
-            monitor->setWidth(jsonMonitor["width"]);
+            if (jsonMonitor.contains("width")) {
+                READER_STEP(step, "monitor -> width");
+                monitor->setWidth(jsonMonitor["width"]);
+            }
 
             // height
-            READER_STEP(step, "monitor -> height");
-            monitor->setHeight(jsonMonitor["height"]);
+            if (jsonMonitor.contains("height")) {
+                READER_STEP(step, "monitor -> height");
+                monitor->setHeight(jsonMonitor["height"]);
+            }
 
             // x
             READER_STEP(step, "monitor -> x");

test/load_project/load_project_test.cpp

@@ -701,3 +701,11 @@ TEST(LoadProjectTest, ProjectInvalidTest)
     ASSERT_EQ(p.scratchVersion(), ScratchVersion::Invalid);
     ASSERT_FALSE(p.load());
 }
+
+TEST(LoadProjectTest, LoadNullDimensionMonitor)
+{
+    // Regtest for #448
+    std::string name = "regtest_projects/448_null_monitor_dimension.sb3";
+    Project p(name);
+    ASSERT_TRUE(p.load());
+}