avm1: `button.enabled = undefined` doesn't disable the button

core/src/avm1/globals/button.rs

@@ -67,6 +67,7 @@ fn enabled<'gc>(
     this: Avm1Button<'gc>,
     _activation: &mut Activation<'_, 'gc>,
 ) -> Result<Value<'gc>, Error<'gc>> {
+    // TODO: This property should return the value set by the user.
     Ok(this.enabled().into())
 }
 
@@ -75,7 +76,11 @@ fn set_enabled<'gc>(
     activation: &mut Activation<'_, 'gc>,
     value: Value<'gc>,
 ) -> Result<(), Error<'gc>> {
-    let enabled = value.as_bool(activation.swf_version());
+    let enabled = if matches!(value, Value::Undefined) {
+        true
+    } else {
+        value.as_bool(activation.swf_version())
+    };
     this.set_enabled(&mut activation.context, enabled);
     Ok(())
 }

core/src/avm1/globals/movie_clip.rs

@@ -1413,6 +1413,7 @@ fn enabled<'gc>(
     this: MovieClip<'gc>,
     _activation: &mut Activation<'_, 'gc>,
 ) -> Result<Value<'gc>, Error<'gc>> {
+    // TODO: This property should return the value set by the user.
     Ok(this.enabled().into())
 }
 
@@ -1421,7 +1422,11 @@ fn set_enabled<'gc>(
     activation: &mut Activation<'_, 'gc>,
     value: Value<'gc>,
 ) -> Result<(), Error<'gc>> {
-    let enabled = value.as_bool(activation.swf_version());
+    let enabled = if matches!(value, Value::Undefined) {
+        true
+    } else {
+        value.as_bool(activation.swf_version())
+    };
     this.set_enabled(&mut activation.context, enabled);
     Ok(())
 }

tests/tests/swfs/avm1/button_enabled_special_cases/input.json

@@ -0,0 +1,45 @@
+[
+    {
+        "type": "MouseMove",
+        "pos": [100.0, 100.0]
+    },
+    {
+        "type": "Wait"
+    },
+    {
+        "type": "Wait"
+    },
+    {
+        "type": "MouseDown",
+        "pos": [100.0, 100.0],
+        "btn": "Left"
+    },
+    {
+        "type": "Wait"
+    },
+    {
+        "type": "Wait"
+    },
+    {
+        "type": "MouseUp",
+        "pos": [100.0, 100.0],
+        "btn": "Left"
+    },
+    {
+        "type": "Wait"
+    },
+    {
+        "type": "Wait"
+    },
+    {
+        "type": "MouseDown",
+        "pos": [100.0, 100.0],
+        "btn": "Left"
+    },
+    {
+        "type": "Wait"
+    },
+    {
+        "type": "Wait"
+    }
+]

tests/tests/swfs/avm1/button_enabled_special_cases/output.txt

@@ -0,0 +1,21 @@
+Step 1: rollOver
+MovieClip.prototype.hasOwnProperty('enabled'): true
+'enabled' in button: true
+button.enabled: true
+// button.enabled = undefined
+'enabled' in button: true
+`button.enabled` is now a falsy value.
+`button.enabled` is undefined.
+
+Step 2: press
+'enabled' in button: true
+`button.enabled` is still a falsy value.
+`button.enabled` is still undefined.
+
+Step 3: release
+// delete button.enabled
+'enabled' in button: true
+`button.enabled` is now true.
+
+Step 4: press
+

tests/tests/swfs/avm1/button_enabled_special_cases/source.txt

@@ -0,0 +1,61 @@
+// Source code for the `rollOver` event.
+// Other events just do `buttonAction("event_name");`.
+
+if(_root.step === undefined) {
+	_root.step = 1;
+	_root.enabledInButton = function() {
+		for(var i in _root.doin) {
+			if(i === "enabled") { return true; }
+		}
+		return false;
+	};
+	_root.buttonAction = function(event) {
+		trace("Step " + step + ": " + event);
+		var button = _root.doin;
+		switch(step) {
+			case 1:
+				// The mouse moved inside of the button area, this triggers the rollOver event.
+				trace("MovieClip.prototype.hasOwnProperty('enabled'): " + MovieClip.prototype.hasOwnProperty("enabled"));
+				trace("'enabled' in button: " + enabledInButton());
+				trace("button.enabled: " + button.enabled);
+				button.enabled = false;
+				button.enabled = undefined;
+				trace("// button.enabled = undefined");
+				trace("'enabled' in button: " + enabledInButton());
+				if(!button.enabled) {
+					trace("`button.enabled` is now a falsy value.");
+					if(button.enabled === undefined) {
+						trace("`button.enabled` is undefined.");
+					}
+				}
+				break;
+			case 2:
+				// The mouse left button was pressed, this triggers the press event.
+				trace("'enabled' in button: " + enabledInButton());
+				if(!button.enabled) {
+					trace("`button.enabled` is still a falsy value.");
+					if(button.enabled === undefined) {
+						trace("`button.enabled` is still undefined.");
+					}
+				}
+				break;
+			case 3:
+				// The mouse left button was released, this triggers the release event.
+				button.enabled = false;
+				delete button.enabled;
+				trace("// delete button.enabled");
+				trace("'enabled' in button: " + enabledInButton());
+				if(button.enabled === true) {
+					trace("`button.enabled` is now true.");
+				}
+				break;
+			case 4:
+				// The mouse left button was pressed, this triggers the press event.
+				break;
+		}
+		trace("");
+		step++;
+	};
+}
+
+buttonAction("rollOver");

tests/tests/swfs/avm1/button_enabled_special_cases/test.toml

@@ -0,0 +1,2 @@
+num_frames = 20
+ignore = true