Better handling of untracked files w.r.t. dirtyDiff

src/vs/editor/common/services/editorWorkerServiceImpl.ts

@@ -102,7 +102,7 @@ class EditorWorkerClient {
 		let modelUrl = resource.toString();
 		let model = this._modelService.getModel(resource);
 		if (!model) {
-			throw new Error('Uknown model!');
+			return;
 		}
 		if (model.isTooLargeForHavingARichMode()) {
 			return;

src/vs/workbench/parts/git/browser/gitWorkbenchContributions.ts

@@ -231,6 +231,12 @@ class DirtyDiffModelDecorator {
 					return; // disposed
 				}
 
+				if (!contents) {
+					// untracked file
+					this.modelService.destroyModel(this._originalContentsURI);
+					return this.triggerDiff();
+				}
+
 				let rawText = TextModel.toRawText(contents);
 				let originalModel = this.modelService.getModel(this._originalContentsURI);