Markup cell initialize fail on window reload

[rebornix]

This is hard to have stable reproduce but almost every one in the notebook v-team ran into this in last few weeks: when reloading the window with a notebook editor open, the notebook editor might not open successfully, closing it and reopening the same document can fix it.

Debugged with log points in Insiders and I found it failed in BacklayerWebview#initializeMarkup

vscode/src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts

Lines 1159 to 1182 in d847171

	if (this._disposed) {
	return;
	}
	// TODO: use proper handler
	const p = new Promise<void>(resolve => {
	const sub = this.webview?.onMessage(e => {
	if (e.message.type === 'initializedMarkup') {
	resolve();
	sub?.dispose();
	}
	});
	});
	for (const cell of cells) {
	this.markupPreviewMapping.set(cell.cellId, cell);
	}
	this._sendMessageToWebview({
	type: 'initializeMarkup',
	cells,
	});
	await p;

The initializeMarkup message is sent to the webview (at least we called the webview postMessage) but the response never came back. When this happens, the webview/iframe contains the html content, Jupyter notebook renderers' styles, but it doesn't have anything related to the markup renderers (no markup css).

@mjbvz please help take a look, we can have a call to do some debugging together.

[mjbvz]

@rebornix I haven't seen this myself but addressed some possible causes with #161550. Let me know if you can reliably reproduce this issue

3f92eb6 also fixed some issues where if a renderer failed to load or threw during loading, we would never load the notebook

[mjbvz]

Closing since we haven’t seen this happening again recently

[IanMatthewHuff]

@rebornix @mjbvz Is it this issue here with a blue cylon but the main document never loads?

I still get this. I opened a document and reloaded and got this on the fourth try (current insiders). Anything I can collect when this happens to help out?