Does not show outputs with JupyterLab 4.3.0b0

[krassowski]

Description

Not sure where the contract is broken, probably on JupyterLab side but just as a heads up the outputs do not show up, an exception is thrown:

TypeError: e.toJSON is not a function
    at jlab_core.abd83dd7cfacd6da4d00.js?v=abd83dd7cfacd6da4d00:1:238328
    at 1168.8e5df3139aa020a611cb.js?v=8e5df3139aa020a611cb:1:551
    at q._onSharedModelChanged (jlab_core.abd83dd7cfacd6da4d00.js?v=abd83dd7cfacd6da4d00:1:238119)
    at m (jlab_core.abd83dd7cfacd6da4d00.js?v=abd83dd7cfacd6da4d00:1:1838868)
    at Object.l [as emit] (jlab_core.abd83dd7cfacd6da4d00.js?v=abd83dd7cfacd6da4d00:1:1838544)
    at a.emit (jlab_core.abd83dd7cfacd6da4d00.js?v=abd83dd7cfacd6da4d00:1:1836381)
    at Array._modelObserver (1168.8e5df3139aa020a611cb.js?v=8e5df3139aa020a611cb:1:7524)
    at Object.r (383.db345dbeef5ef774e50c.js?v=db345dbeef5ef774e50c:1:936)
    at ji (383.db345dbeef5ef774e50c.js?v=db345dbeef5ef774e50c:1:43499)
    at Array.<anonymous> (383.db345dbeef5ef774e50c.js?v=db345dbeef5ef774e50c:1:52559)

Reproduce

• Install pip install jupyter_server_nbmodel[lab] jupyterlab>=4.3.0b0 jupyter-ydoc>=3.0.0a3
• Run cell with 1 + 1
• See no output

Expected behavior

2

Context

• v0.1.1a1
• Improve stream output handling jupyterlab/jupyterlab#16498

[krassowski]

It looks like we've got quite some work to do here:

jupyter-server-nbmodel/jupyter_server_nbmodel/handlers.py

Lines 140 to 174 in 0a6c683

	# FIXME support for version
	output = nbformat.v4.output_from_msg(msg)
	outputs.append(output)
	if ycell is not None:
	cell_outputs = ycell["outputs"]
	if msg_type == "stream":
	with cell_outputs.doc.transaction():
	text = output["text"]
	# FIXME Logic is quite complex at https://github.com/jupyterlab/jupyterlab/blob/7ae2d436fc410b0cff51042a3350ba71f54f4445/packages/outputarea/src/model.ts#L518
	if text.endswith((os.linesep, "\n")):
	text = text[:-1]
	if (not cell_outputs) or (cell_outputs[-1]["name"] != output["name"]):
	output["text"] = [text]
	cell_outputs.append(output)
	else:
	last_output = cell_outputs[-1]
	last_output["text"].append(text)
	cell_outputs[-1] = last_output
	else:
	with cell_outputs.doc.transaction():
	cell_outputs.append(output)
	elif msg_type == "clear_output":
	# FIXME msg.content.wait - if true should clear at the next message
	outputs.clear()
	if ycell is not None:
	del ycell["outputs"][:]
	elif msg_type == "update_display_data":
	# FIXME
	...