Ability to revise assignments

[randy3k]

It seems that there is no "return" when an assignment is released and students have fetched and downloaded the assignment. It would be nice to have the ability to revise assignments.

I haven't figured out the implementation, just think it is a nice feature to have.

[jhamrick]

You mean revision by the instructor (e.g. to fix a mistake in the instructions)?

[randy3k]

Yes, sorry for being not clear.

[dsblank]

Perhaps rather than trying to revise an assignment (where students may have already started answering the questions) it is better to focus on preventing the need to make such revisions. For example, in #552 I suggest easier methods to Preview and proofread.

[randy3k]

Since each cell has its own id, I guess it is still possible to compare changes between student already working notebook and the revision, and then merge the changes.

The need of revision is not always preventable. :(

[randy3k]

I am currently using this code to revise assignments.

Basically, it uses the revised notebook as a skeleton and replaces the solution cells from the student notebooks.

[jhamrick]

This is really useful @randy3k ! I am not sure if there is a super great way to incorporate this into nbgrader proper (at least at the moment) but there is definitely a need for something like this. Hopefully other people will find this useful in the meantime.

[nabriis]

I think this is important.
Suggestion:

1. Make it visible under the Assignments tab if a new version of the assignments is released
   (done by saving time and date notebook was generated by nbgrader)
   Create a button "Download new version" for downloading the new version of the assignment (with a warning) and saving the edited student version as another folder. (useful if no or few edits from the student has been done).

2. Create a "merge" button that merges the students work with the new version of the assignment (ala. the code given here). This should replace the "Download new version" with "Download new version and merge".

Could start with 1) and then develop 2) further down the road.

[jhamrick]

That sounds like a reasonable way to do it. I don't want to deal with implementing a "merge" functionality (I think this would be really difficult to implement properly and would be hard to maintain and debug), but the suggestion of copying the original assignment to a backup folder seems reasonable---it would be a bit annoying for students because they would then have to copy and paste any solutions that they had so far, but it wouldn't be the end of the world.