Strict null check mainThreadEditors

src/tsconfig.strictNullChecks.json

@@ -58,7 +58,10 @@
 		"./vs/workbench/api/electron-browser/mainThreadDiagnostics.ts",
 		"./vs/workbench/api/electron-browser/mainThreadDialogs.ts",
 		"./vs/workbench/api/electron-browser/mainThreadDocumentContentProviders.ts",
+		"./vs/workbench/api/electron-browser/mainThreadDocuments.ts",
+		"./vs/workbench/api/electron-browser/mainThreadDocumentsAndEditors.ts",
 		"./vs/workbench/api/electron-browser/mainThreadEditor.ts",
+		"./vs/workbench/api/electron-browser/mainThreadEditors.ts",
 		"./vs/workbench/api/electron-browser/mainThreadErrors.ts",
 		"./vs/workbench/api/electron-browser/mainThreadFileSystem.ts",
 		"./vs/workbench/api/electron-browser/mainThreadFileSystemEventService.ts",
@@ -257,13 +260,13 @@
 		"./vs/workbench/contrib/debug/browser/exceptionWidget.ts",
 		"./vs/workbench/contrib/debug/browser/linkDetector.ts",
 		"./vs/workbench/contrib/debug/browser/statusbarColorProvider.ts",
-		"./vs/workbench/contrib/debug/electron-browser/debugHover.ts",
 		"./vs/workbench/contrib/debug/electron-browser/breakpointWidget.ts",
 		"./vs/workbench/contrib/debug/electron-browser/debugEditorContribution.ts",
+		"./vs/workbench/contrib/debug/electron-browser/debugHover.ts",
 		"./vs/workbench/contrib/debug/electron-browser/electronDebugActions.ts",
 		"./vs/workbench/contrib/debug/electron-browser/rawDebugSession.ts",
-		"./vs/workbench/contrib/debug/electron-browser/variablesView.ts",
 		"./vs/workbench/contrib/debug/electron-browser/repl.ts",
+		"./vs/workbench/contrib/debug/electron-browser/variablesView.ts",
 		"./vs/workbench/contrib/debug/electron-browser/watchExpressionsView.ts",
 		"./vs/workbench/contrib/debug/test/browser/baseDebugView.test.ts",
 		"./vs/workbench/contrib/debug/test/common/debugSource.test.ts",
@@ -524,6 +527,7 @@
 		"./vs/workbench/test/electron-browser/api/mainThreadConfiguration.test.ts",
 		"./vs/workbench/test/electron-browser/api/mainThreadDiagnostics.test.ts",
 		"./vs/workbench/test/electron-browser/api/mainThreadDocumentContentProviders.test.ts",
+		"./vs/workbench/test/electron-browser/api/mainThreadDocuments.test.ts",
 		"./vs/workbench/test/electron-browser/api/mock.ts",
 		"./vs/workbench/test/electron-browser/api/testRPCProtocol.ts",
 		"./vs/workbench/test/electron-browser/colorRegistry.releaseTest.ts"

src/vs/workbench/api/electron-browser/mainThreadEditors.ts

@@ -242,12 +242,16 @@ export class MainThreadTextEditors implements MainThreadTextEditorsShape {
 		}
 
 		const codeEditor = editor.getCodeEditor();
+		if (!codeEditor) {
+			return Promise.reject(new Error('No such CodeEditor'));
+		}
+
 		const codeEditorId = codeEditor.getId();
 		const diffEditors = this._codeEditorService.listDiffEditors();
 		const [diffEditor] = diffEditors.filter(d => d.getOriginalEditor().getId() === codeEditorId || d.getModifiedEditor().getId() === codeEditorId);
 
 		if (diffEditor) {
-			return Promise.resolve(diffEditor.getLineChanges());
+			return Promise.resolve(diffEditor.getLineChanges() || []);
 		}
 
 		const dirtyDiffContribution = codeEditor.getContribution('editor.contrib.dirtydiff');