check that output exists (microsoft#233011)

Author: amunger

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

@@ -3065,12 +3065,16 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditorD
 		const cell = this.viewModel?.viewCells.find(vc => vc.handle === cellInfo.cellHandle);
 		if (cell && cell instanceof CodeCellViewModel) {
 			const outputIndex = cell.outputsViewModels.indexOf(output);
-			this._debug('update cell output', cell.handle, outputHeight);
-			cell.updateOutputHeight(outputIndex, outputHeight, source);
-			this.layoutNotebookCell(cell, cell.layoutInfo.totalHeight);
+			if (outputIndex > -1) {
+				this._debug('update cell output', cell.handle, outputHeight);
+				cell.updateOutputHeight(outputIndex, outputHeight, source);
+				this.layoutNotebookCell(cell, cell.layoutInfo.totalHeight);
 
-			if (isInit) {
-				this._onDidRenderOutput.fire(output);
+				if (isInit) {
+					this._onDidRenderOutput.fire(output);
+				}
+			} else {
+				this._debug('tried to update cell output that does not exist');
 			}
 		}
 	}

src/vs/workbench/contrib/notebook/browser/viewModel/codeCellViewModel.ts

@@ -446,10 +446,16 @@ export class CodeCellViewModel extends BaseCellViewModel implements ICellViewMod
 
 		this._ensureOutputsTop();
 
-		if (index === 0 || height > 0) {
-			this._outputViewModels[index].setVisible(true);
-		} else if (height === 0) {
-			this._outputViewModels[index].setVisible(false);
+		try {
+			if (index === 0 || height > 0) {
+				this._outputViewModels[index].setVisible(true);
+			} else if (height === 0) {
+				this._outputViewModels[index].setVisible(false);
+			}
+		} catch (e) {
+			const errorMessage = `Failed to update output height for cell ${this.handle}, output ${index}. `
+				+ `this.outputCollection.length: ${this._outputCollection.length}, this._outputViewModels.length: ${this._outputViewModels.length}`;
+			throw new Error(`${errorMessage}.\n Error: ${e.message}`);
 		}
 
 		if (this._outputViewModels[index].visible.get() && height < 28) {