editors - clearInput before setInput (#34697)

src/vs/workbench/browser/parts/editor/editor.ts

@@ -39,7 +39,8 @@ export const DEFAULT_EDITOR_PART_OPTIONS: IEditorPartOptions = {
 	closeEmptyGroups: true,
 	labelFormat: 'default',
 	splitSizing: 'distribute',
-	splitOnDragAndDrop: true
+	splitOnDragAndDrop: true,
+	experimentalDisableClearInputOnSetInput: false //TODO@bpasero remove this setting in December
 };
 
 export function impactsEditorPartOptions(event: IConfigurationChangeEvent): boolean {

src/vs/workbench/browser/parts/editor/editorGroupView.ts

@@ -211,7 +211,7 @@ export class EditorGroupView extends Themable implements IEditorGroupView {
 			this.element.appendChild(this.editorContainer);
 
 			// Editor pane
-			this.editorPane = this._register(this.scopedInstantiationService.createInstance(EditorPanes, this.editorContainer, this));
+			this.editorPane = this._register(this.scopedInstantiationService.createInstance(EditorPanes, this.editorContainer, this.accessor, this));
 			this._onDidChange.input = this.editorPane.onDidChangeSizeConstraints;
 
 			// Track Focus

src/vs/workbench/browser/parts/editor/editorPane.ts

@@ -122,7 +122,8 @@ export abstract class EditorPane extends Composite implements IEditorPane {
 	 * resources associated with the input should be freed.
 	 *
 	 * This method can be called based on different contexts, e.g. when opening
-	 * a different editor control or when closing all editors in a group.
+	 * a different input or different editor control or when closing all editors
+	 * in a group.
 	 *
 	 * To monitor the lifecycle of editor inputs, you should not rely on this
 	 * method, rather refer to the listeners on `IEditorGroup` via `IEditorGroupService`.

src/vs/workbench/browser/parts/editor/editorPanes.ts

@@ -13,7 +13,7 @@ import { IWorkbenchLayoutService } from 'vs/workbench/services/layout/browser/la
 import { EditorPane } from 'vs/workbench/browser/parts/editor/editorPane';
 import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation';
 import { IEditorProgressService, LongRunningOperation } from 'vs/platform/progress/common/progress';
-import { IEditorGroupView, DEFAULT_EDITOR_MIN_DIMENSIONS, DEFAULT_EDITOR_MAX_DIMENSIONS } from 'vs/workbench/browser/parts/editor/editor';
+import { IEditorGroupView, DEFAULT_EDITOR_MIN_DIMENSIONS, DEFAULT_EDITOR_MAX_DIMENSIONS, IEditorGroupsAccessor } from 'vs/workbench/browser/parts/editor/editor';
 import { Emitter } from 'vs/base/common/event';
 import { assertIsDefined } from 'vs/base/common/types';
 import { IWorkspaceTrustManagementService } from 'vs/platform/workspace/common/workspaceTrust';
@@ -84,6 +84,7 @@ export class EditorPanes extends Disposable {
 
 	constructor(
 		private parent: HTMLElement,
+		private accessor: IEditorGroupsAccessor,
 		private groupView: IEditorGroupView,
 		@IWorkbenchLayoutService private readonly layoutService: IWorkbenchLayoutService,
 		@IInstantiationService private readonly instantiationService: IInstantiationService,
@@ -268,9 +269,18 @@ export class EditorPanes extends Disposable {
 		// started will cancel the previous one.
 		const operation = this.editorOperation.start(this.layoutService.isRestored() ? 800 : 3200);
 
-		// Set the input to the editor pane
 		let cancelled = false;
 		try {
+
+			// Clear the current input before setting new input
+			// This ensures that a slow loading input will not
+			// be visible for the duration of the new input to
+			// load (https://github.com/microsoft/vscode/issues/34697)
+			if (this.accessor.partOptions.experimentalDisableClearInputOnSetInput !== true) {
+				editorPane.clearInput();
+			}
+
+			// Set the input to the editor pane
 			await editorPane.setInput(editor, options, context, operation.token);
 
 			if (!operation.isCurrent()) {
@@ -309,7 +319,7 @@ export class EditorPanes extends Disposable {
 	}
 
 	closeEditor(editor: EditorInput): void {
-		if (this._activeEditorPane && this._activeEditorPane.input && editor.matches(this._activeEditorPane.input)) {
+		if (this._activeEditorPane?.input && editor.matches(this._activeEditorPane.input)) {
 			this.doHideActiveEditorPane();
 		}
 	}

src/vs/workbench/browser/parts/editor/editorWithViewState.ts

@@ -17,8 +17,6 @@ import { IEditorService } from 'vs/workbench/services/editor/common/editorServic
 import { IExtUri } from 'vs/base/common/resources';
 import { IDisposable, MutableDisposable } from 'vs/base/common/lifecycle';
 import { EditorInput } from 'vs/workbench/common/editor/editorInput';
-import { IEditorOptions } from 'vs/platform/editor/common/editor';
-import { CancellationToken } from 'vs/base/common/cancellation';
 
 /**
  * Base class of editors that want to store and restore view state.
@@ -65,14 +63,6 @@ export abstract class AbstractEditorWithViewState<T extends object> extends Edit
 		}
 	}
 
-	override async setInput(input: EditorInput, options: IEditorOptions | undefined, context: IEditorOpenContext, token: CancellationToken): Promise<void> {
-
-		// Preserve current input view state before opening new
-		this.updateEditorViewState(this.input);
-
-		await super.setInput(input, options, context, token);
-	}
-
 	override clearInput(): void {
 
 		// Preserve current input view state before clearing

src/vs/workbench/browser/workbench.contribution.ts

@@ -241,6 +241,11 @@ const registry = Registry.as<IConfigurationRegistry>(ConfigurationExtensions.Con
 				'default': false,
 				'description': localize('perEditorGroup', "Controls if the limit of maximum opened editors should apply per editor group or across all editor groups.")
 			},
+			'workbench.editor.experimentalDisableClearInputOnSetInput': {
+				'type': 'boolean',
+				'default': false,
+				'description': localize('experimentalDisableClearInputOnSetInput', "Experimental setting: do not change unless instructed.")
+			},
 			'workbench.commandPalette.history': {
 				'type': 'number',
 				'description': localize('commandHistory', "Controls the number of recently used commands to keep in history for the command palette. Set to 0 to disable command history."),

src/vs/workbench/common/editor.ts

@@ -864,7 +864,8 @@ interface IEditorPartConfiguration {
 	decorations?: {
 		badges?: boolean;
 		colors?: boolean;
-	}
+	},
+	experimentalDisableClearInputOnSetInput?: boolean;
 }
 
 export interface IEditorPartOptions extends IEditorPartConfiguration {

src/vs/workbench/contrib/notebook/browser/notebookEditor.ts

@@ -175,8 +175,6 @@ export class NotebookEditor extends EditorPane {
 
 		this.inputListener.value = input.onDidChangeCapabilities(() => this.onDidChangeInputCapabilities(input));
 
-		this._saveEditorViewState(this.input);
-
 		this._widgetDisposableStore.clear();
 
 		// there currently is a widget which we still own so

src/vs/workbench/contrib/welcome/walkThrough/browser/walkThroughPart.ts

@@ -268,10 +268,6 @@ export class WalkThroughPart extends EditorPane {
 	}
 
 	override setInput(input: WalkThroughInput, options: IEditorOptions | undefined, context: IEditorOpenContext, token: CancellationToken): Promise<void> {
-		if (this.input instanceof WalkThroughInput) {
-			this.saveTextEditorViewState(this.input);
-		}
-
 		const store = new DisposableStore();
 		this.contentDisposables.push(store);