Avoid registering disposables when Notebook Edit session is disposed (microsoft#258664)

Author: DonJayamanne

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

@@ -969,17 +969,31 @@ export class ChatEditingModifiedNotebookEntry extends AbstractChatEditingModifie
 		if (!cell) {
 			throw new Error('Cell not found');
 		}
-		const model = this.cellTextModelMap.get(cell.uri) || this._register(await this.textModelService.createModelReference(cell.uri)).object.textEditorModel;
-		this.cellTextModelMap.set(cell.uri, model);
-		return model;
+		const model = this.cellTextModelMap.get(cell.uri);
+		if (model) {
+			this.cellTextModelMap.set(cell.uri, model);
+			return model;
+		} else {
+			const textEditorModel = await this.textModelService.createModelReference(cell.uri);
+			if (this._store.isDisposed) {
+				textEditorModel.dispose();
+			} else {
+				this._register(textEditorModel);
+			}
+			const model = textEditorModel.object.textEditorModel;
+			this.cellTextModelMap.set(cell.uri, model);
+			return model;
+		}
 	}
 
 	getOrCreateModifiedTextFileEntryForCell(cell: NotebookCellTextModel, modifiedCellModel: ITextModel, originalCellModel: ITextModel): ChatEditingNotebookCellEntry | undefined {
 		let cellEntry = this.cellEntryMap.get(cell.uri);
 		if (cellEntry) {
 			return cellEntry;
 		}
-
+		if (this._store.isDisposed) {
+			return;
+		}
 		const disposables = new DisposableStore();
 		cellEntry = this._register(this._instantiationService.createInstance(ChatEditingNotebookCellEntry, this.modifiedResourceRef.object.resource, cell, modifiedCellModel, originalCellModel, disposables));
 		this.cellEntryMap.set(cell.uri, cellEntry);