Multi-Directory notebooks overwrite each other's checkpoints

[manuteleco]

IPython version: 71ff8f9 (after 2.0)

Even though I haven't seen any open issue about this yet, I believe it might be already known, given that it is mentioned here: https://github.com/ipython/ipython/wiki/IPEP-16%3A-Notebook-multi-directory-dashboard-and-URL-mapping#create-a-checkpoint

In brief, the problem is that notebooks that have the same name will write/read the same checkpoint file, regardless of the notebooks' path.

Example:
Notebooks /test.ipynb and /some_path/test.ipynb will both have their checkpoint file named test-checkpoint.ipynb directly under .ipynb_checkpoints.

The consequence of this is that if two or more notebooks located in different subdirectories happen to have the same name they will overwrite each other's checkpoints. A potential solution could be to save the checkpoints in subdirectories as well.

[minrk]

Should be fixed by #5708

[takluyver]

Or rather, #5708.