guard against broken SVG costumes when loading a project

HISTORY.md

@@ -5,6 +5,7 @@
     * export / import sprite-local custom block definitions, under construction
 * **Notable Changes:**
 * **Notable Fixes:**
+    * guard against broken SVG costumes when loading a project
 * **Documentation Updates:**
 * **Translation Updates:**
 
@@ -13,6 +14,7 @@
 * byob, store, gui: export / import sprite-local custom block definitions, under construction
 * byob, gui: adapted library import dialog to the new format
 * byob: added collecting dependencies for sprite-local custom blocks
+* objects: guard against broken SVG costumes when loading a project
 
 ## 7.3.0:
 * **New Features:**

snap.html

@@ -18,7 +18,7 @@
         <script src="src/widgets.js?version=2021-17-09"></script>
         <script src="src/blocks.js?version=2022-03-07"></script>
         <script src="src/threads.js?version=2022-03-03"></script>
-        <script src="src/objects.js?version=2022-03-01"></script>
+        <script src="src/objects.js?version=2022-03-09"></script>
         <script src="src/scenes.js?version=2022-03-03"></script>
         <script src="src/gui.js?version=2022-03-09"></script>
         <script src="src/paint.js?version=2021-07-05"></script>

src/objects.js

@@ -87,7 +87,7 @@ BlockVisibilityDialogMorph, CostumeIconMorph, SoundIconMorph*/
 
 /*jshint esversion: 6*/
 
-modules.objects = '2022-March-04';
+modules.objects = '2022-March-09';
 
 var SpriteMorph;
 var StageMorph;
@@ -10352,11 +10352,11 @@ Costume.prototype.center = function () {
 };
 
 Costume.prototype.width = function () {
-    return this.contents.width;
+    return this.contents ? this.contents.width : 0;
 };
 
 Costume.prototype.height = function () {
-    return this.contents.height;
+    return this.contents ? this.contents.height : 0;
 };
 
 Costume.prototype.bounds = function () {