Handle no modification scenario in chat editing (microsoft#239207)

* Remove/dispose modified files if they turn out to not contain modifications

* Only start only accept flow when done streaming, reset when no edits come along

fixes microsoft/vscode-copilot#10413

Author: jrieken

src/vs/workbench/contrib/chat/browser/chatEditing/chatEditingModifiedFileEntry.ts

@@ -293,16 +293,12 @@ export class ChatEditingModifiedFileEntry extends Disposable implements IModifie
 
 	acceptStreamingEditsStart(tx: ITransaction) {
 		this._resetEditsState(tx);
+		this._autoAcceptCtrl.get()?.cancel();
 	}
 
-	acceptStreamingEditsEnd(tx: ITransaction) {
+	async acceptStreamingEditsEnd(tx: ITransaction) {
 		this._resetEditsState(tx);
-	}
-
-	private _resetEditsState(tx: ITransaction): void {
-		this._isCurrentlyBeingModifiedObs.set(false, tx);
-		this._rewriteRatioObs.set(0, tx);
-		this._clearCurrentEditLineDecoration();
+		await this._diffOperation;
 
 		// AUTO accept mode
 		if (!this.reviewMode.get() && !this._autoAcceptCtrl.get()) {
@@ -333,6 +329,12 @@ export class ChatEditingModifiedFileEntry extends Disposable implements IModifie
 		}
 	}
 
+	private _resetEditsState(tx: ITransaction): void {
+		this._isCurrentlyBeingModifiedObs.set(false, tx);
+		this._rewriteRatioObs.set(0, tx);
+		this._clearCurrentEditLineDecoration();
+	}
+
 	private _mirrorEdits(event: IModelContentChangedEvent) {
 		const edit = OffsetEdits.fromContentChanges(event.changes);
 

src/vs/workbench/contrib/chat/browser/chatEditing/chatEditingSession.ts

@@ -11,7 +11,7 @@ import { StringSHA1 } from '../../../../../base/common/hash.js';
 import { Disposable, DisposableMap, DisposableStore, dispose } from '../../../../../base/common/lifecycle.js';
 import { ResourceMap, ResourceSet } from '../../../../../base/common/map.js';
 import { Schemas } from '../../../../../base/common/network.js';
-import { autorun, derived, IObservable, IReader, ITransaction, observableValue, transaction } from '../../../../../base/common/observable.js';
+import { asyncTransaction, autorun, derived, IObservable, IReader, ITransaction, observableValue, transaction } from '../../../../../base/common/observable.js';
 import { autorunDelta, autorunIterableDelta } from '../../../../../base/common/observableInternal/autorun.js';
 import { isEqual, joinPath } from '../../../../../base/common/resources.js';
 import { URI } from '../../../../../base/common/uri.js';
@@ -735,9 +735,22 @@ export class ChatEditingSession extends Disposable implements IChatEditingSessio
 	}
 
 	private async _resolve(): Promise<void> {
-		transaction((tx) => {
+		await asyncTransaction(async (tx) => {
+
+			const entriesWithoutChange = new ResourceMap<ChatEditingModifiedFileEntry>();
+
 			for (const entry of this._entriesObs.get()) {
-				entry.acceptStreamingEditsEnd(tx);
+				await entry.acceptStreamingEditsEnd(tx);
+				if (entry.diffInfo.get().identical) {
+					entriesWithoutChange.set(entry.modifiedURI, entry);
+				}
+			}
+
+			if (entriesWithoutChange.size > 0) {
+				const newEntries = this._entriesObs.get().filter(e => !entriesWithoutChange.has(e.modifiedURI));
+				this._entriesObs.set(newEntries, tx);
+
+				dispose(entriesWithoutChange.values());
 			}
 			this._state.set(ChatEditingSessionState.Idle, tx);
 		});

src/vs/workbench/contrib/chat/browser/chatEditorController.ts

@@ -37,6 +37,7 @@ import { ChatAgentLocation, IChatAgentService } from '../common/chatAgents.js';
 import { EditorsOrder, IEditorIdentifier, isDiffEditorInput } from '../../../common/editor.js';
 import { ChatEditorOverlayController } from './chatEditorOverlay.js';
 import { IChatService } from '../common/chatService.js';
+import { StableEditorScrollState } from '../../../../editor/browser/stableEditorScroll.js';
 
 export const ctxIsGlobalEditingSession = new RawContextKey<boolean>('chat.isGlobalEditingSession', undefined, localize('chat.ctxEditSessionIsGlobal', "The current editor is part of the global edit session"));
 export const ctxHasEditorModification = new RawContextKey<boolean>('chat.hasEditorModifications', undefined, localize('chat.hasEditorModifications', "The current editor contains chat modifications"));
@@ -114,9 +115,7 @@ export class ChatEditorController extends Disposable implements IEditorContribut
 
 			for (const session of _chatEditingService.editingSessionsObs.read(r)) {
 				const entries = session.entries.read(r);
-				const idx = model?.uri
-					? entries.findIndex(e => isEqual(e.modifiedURI, model.uri))
-					: -1;
+				const idx = entries.findIndex(e => isEqual(e.modifiedURI, model.uri));
 
 				const chatModel = chatService.getSession(session.chatSessionId);
 
@@ -129,7 +128,7 @@ export class ChatEditorController extends Disposable implements IEditorContribut
 		});
 
 
-		let didReval = false;
+		let scrollState: StableEditorScrollState | undefined = undefined;
 
 		this._register(autorunWithStore((r, store) => {
 
@@ -138,7 +137,7 @@ export class ChatEditorController extends Disposable implements IEditorContribut
 			if (!currentEditorEntry) {
 				this._ctxIsGlobalEditsSession.reset();
 				this._clear();
-				didReval = false;
+				scrollState = undefined;
 				return;
 			}
 
@@ -149,10 +148,10 @@ export class ChatEditorController extends Disposable implements IEditorContribut
 
 			const { session, chatModel, entries, idx, entry } = currentEditorEntry;
 
-			store.add(chatModel.onDidChange(e => {
-				if (e.kind === 'addRequest') {
-					didReval = false;
-				}
+			const lastRequestSignal = observableFromEvent(this, chatModel.onDidChange, () => chatModel.getRequests().at(-1));
+			store.add(autorun(r => {
+				lastRequestSignal.read(r);
+				scrollState ??= StableEditorScrollState.capture(this._editor);
 			}));
 
 			this._ctxIsGlobalEditsSession.set(session.isGlobalEditingSession);
@@ -193,7 +192,7 @@ export class ChatEditorController extends Disposable implements IEditorContribut
 				fontInfoObs.read(r);
 				lineHeightObs.read(r);
 
-				const diff = entry?.diffInfo.read(r);
+				const diff = entry.diffInfo.read(r);
 
 				// Add line decorations (just markers, no UI) for diff navigation
 				this._updateDiffLineDecorations(diff);
@@ -207,9 +206,13 @@ export class ChatEditorController extends Disposable implements IEditorContribut
 					this._clearDiffRendering();
 				}
 
-				if (!didReval && !diff.identical) {
-					didReval = true;
-					this._reveal(true, false, ScrollType.Immediate);
+				if (lastRequestSignal.read(r)?.response?.isComplete) {
+					if (!diff.identical) {
+						this._reveal(true, false, ScrollType.Immediate);
+					} else {
+						scrollState?.restore(_editor);
+						scrollState = undefined;
+					}
 				}
 			}
 		}));