Provide a log of unhandled output

[jasongrout]

With widgets as outputs, they may have output that is unhandled and has no specific cell to be displayed. It would be great if there was some sort of log area where any unhandled output in the notebook could be stored (and rendered if the log is displayed) to aid in debugging.

[jasongrout]

We may have a workaround for widgets in jupyter-widgets/ipywidgets#1321, but there still is the overall issue of how to deal with unhandled, orphaned output.

[takluyver]

👍

We probably can't keep it all forever, but I could see keeping a rolling buffer of N recent lines, accessible in a dialog. Once we move the notebook model to the server, it could go one better and log uncaptured output to a file.

[maartenbreddels]

indeed 👍 , Maybe Output indeed should implement such a buffer, but I'd keep it simple and just have a simple implementation first without one. But how to display such a buffer? It it does not happen automatically, it won't help much people. Maybe sth like when output is written to, and _view_count == 0, we should display it?