Crash on image/panel not found and add TryGet functions for searching

OpenRA.Game/Graphics/ChromeProvider.cs

@@ -144,6 +144,15 @@ static void LoadCollection(string name, MiniYaml yaml)
 		}
 
 		public static Sprite GetImage(string collectionName, string imageName)
+		{
+			var image = TryGetImage(collectionName, imageName);
+			if (image == null)
+				throw new ArgumentException($"Sprite `{collectionName}/{imageName}` was not found.");
+
+			return image;
+		}
+
+		public static Sprite TryGetImage(string collectionName, string imageName)
 		{
 			if (string.IsNullOrEmpty(collectionName))
 				return null;
@@ -153,10 +162,7 @@ public static Sprite GetImage(string collectionName, string imageName)
 				return sprite;
 
 			if (!collections.TryGetValue(collectionName, out var collection))
-			{
-				Log.Write("debug", "Could not find collection '{0}'", collectionName);
 				return null;
-			}
 
 			if (!collection.Regions.TryGetValue(imageName, out var mi))
 				return null;
@@ -176,6 +182,15 @@ public static Sprite GetImage(string collectionName, string imageName)
 		}
 
 		public static Sprite[] GetPanelImages(string collectionName)
+		{
+			var panel = TryGetPanelImages(collectionName);
+			if (panel == null)
+				throw new ArgumentException($"Panel `{collectionName}` was not found.");
+
+			return panel;
+		}
+
+		public static Sprite[] TryGetPanelImages(string collectionName)
 		{
 			if (string.IsNullOrEmpty(collectionName))
 				return null;
@@ -185,17 +200,14 @@ public static Sprite[] GetPanelImages(string collectionName)
 				return cachedSprites;
 
 			if (!collections.TryGetValue(collectionName, out var collection))
-			{
-				Log.Write("debug", "Could not find collection '{0}'", collectionName);
 				return null;
-			}
 
 			Sprite[] sprites;
 			if (collection.PanelRegion != null)
 			{
 				if (collection.PanelRegion.Length != 8)
 				{
-					Log.Write("debug", "Collection '{0}' does not define a valid PanelRegion", collectionName);
+					Log.Write("debug", $"Collection '{collectionName}' does not define a valid PanelRegion");
 					return null;
 				}
 
@@ -222,18 +234,23 @@ public static Sprite[] GetPanelImages(string collectionName)
 			}
 			else
 			{
+				// PERF: We don't need to search for images if there are no definitions.
+				// PERF: It's more efficient to send an empty array rather than an array of 9 nulls.
+				if (!collection.Regions.Any())
+					return Array.Empty<Sprite>();
+
 				// Support manual definitions for unusual dialog layouts
 				sprites = new[]
 				{
-					GetImage(collectionName, "corner-tl"),
-					GetImage(collectionName, "border-t"),
-					GetImage(collectionName, "corner-tr"),
-					GetImage(collectionName, "border-l"),
-					GetImage(collectionName, "background"),
-					GetImage(collectionName, "border-r"),
-					GetImage(collectionName, "corner-bl"),
-					GetImage(collectionName, "border-b"),
-					GetImage(collectionName, "corner-br")
+					TryGetImage(collectionName, "corner-tl"),
+					TryGetImage(collectionName, "border-t"),
+					TryGetImage(collectionName, "corner-tr"),
+					TryGetImage(collectionName, "border-l"),
+					TryGetImage(collectionName, "background"),
+					TryGetImage(collectionName, "border-r"),
+					TryGetImage(collectionName, "corner-bl"),
+					TryGetImage(collectionName, "border-b"),
+					TryGetImage(collectionName, "corner-br")
 				};
 			}
 

OpenRA.Mods.Common/Widgets/ImageWidget.cs

@@ -33,14 +33,7 @@ public class ImageWidget : Widget
 		public Func<string> GetTooltipText;
 
 		readonly CachedTransform<(string, string), Sprite> getImageCache = new CachedTransform<(string, string), Sprite>(
-			((string collection, string image) args) =>
-			{
-				var sprite = ChromeProvider.GetImage(args.collection, args.image);
-				if (sprite == null)
-					throw new ArgumentException($"Sprite {args.collection}/{args.image} was not found.");
-
-				return sprite;
-			});
+			((string collection, string image) args) => ChromeProvider.GetImage(args.collection, args.image));
 
 		public ImageWidget()
 		{

OpenRA.Mods.Common/Widgets/ScrollItemWidget.cs

@@ -64,10 +64,7 @@ public override void Draw()
 			if (!IgnoreChildMouseOver && !hover)
 				hover = Children.Contains(Ui.MouseOverWidget);
 
-			var panel = getPanelCache.Update((IsDisabled(), Depressed, hover, false, IsSelected() || IsHighlighted()));
-
-			if (panel != null)
-				WidgetUtils.DrawPanel(RenderBounds, panel);
+			WidgetUtils.DrawPanel(RenderBounds, getPanelCache.Update((IsDisabled(), Depressed, hover, false, IsSelected() || IsHighlighted())));
 		}
 
 		public override Widget Clone() { return new ScrollItemWidget(this); }

OpenRA.Mods.Common/Widgets/WidgetUtils.cs

@@ -38,7 +38,7 @@ public static CachedTransform<(bool Disabled, bool Pressed, bool Hover, bool Foc
 					{
 						var collectionName = collection + (args.Highlighted ? "-highlighted" : "");
 						var variantImageName = GetStatefulImageName(imageName, args.Disabled, args.Pressed, args.Hover, args.Focused);
-						return ChromeProvider.GetImage(collectionName, variantImageName) ?? ChromeProvider.GetImage(collectionName, imageName);
+						return ChromeProvider.TryGetImage(collectionName, variantImageName) ?? ChromeProvider.GetImage(collectionName, imageName);
 					});
 		}
 
@@ -50,7 +50,7 @@ public static CachedTransform<(bool Disabled, bool Pressed, bool Hover, bool Foc
 					{
 						var collectionName = collection + (args.Highlighted ? "-highlighted" : "");
 						var variantCollectionName = GetStatefulImageName(collectionName, args.Disabled, args.Pressed, args.Hover, args.Focused);
-						return ChromeProvider.GetPanelImages(variantCollectionName) ?? ChromeProvider.GetPanelImages(collectionName);
+						return ChromeProvider.TryGetPanelImages(variantCollectionName) ?? ChromeProvider.GetPanelImages(collectionName);
 					});
 		}
 
@@ -78,7 +78,7 @@ public static void DrawSpriteCentered(Sprite s, PaletteReference p, float2 pos,
 
 		public static void DrawPanel(string collection, Rectangle bounds)
 		{
-			var sprites = ChromeProvider.GetPanelImages(collection);
+			var sprites = ChromeProvider.TryGetPanelImages(collection);
 			if (sprites != null)
 				DrawPanel(bounds, sprites);
 		}