Nicer error handling in new version of entity

[mirams]

This is about when trying to make a new version of an entity, by deleting and upload a new protocol file.

If I do the file changes, but then do something that's not allowed (leave spaces in the tag name) then I get an error message (which could be a bit more helpful, it just says Git command error: stderr: 'fatal: 'conductance can be dervied quantity' is not a valid tag name.', but all the changes I have done disappear. Would be nice to get the error message and keep the changes to the files.

[jonc125]

I'm not sure how easy that would be to do, as it's a complex interaction between the JS code and Django file uploads. But possibly if we added some Django validation to the field to catch the most common errors, it would do something intelligent!

Edit: unfortunately it isn't that intelligent, so we'll need to think it through instead.

[jonc125]

Relevant sections of code are:

• entities/views.py:EntityNewVersionView
• static/js/upload.js
• templates/entities/includes/version_files.html (and upload.html but I don't think that needs changing)

I suspect we might need to add logic in get_context_data that checks request.POST and adds additions and deletions to the context. And version_files.html can then use these to add extra rows for already-uploaded files, and add hidden delete_filename[] inputs for files marked for deletion.

However, we may wish to rethink how info is passed between the JS, form and view code, since it's already tricky to decipher cases where a user replaces an existing file, or uploads a file then decides it was a mistake and deletes it again before creating a new version, etc. So maybe having lists of filenames[] and delete_filenames[] isn't the best approach, and we should use a structure that reflects the order/detail of actions taken? Not sure yet what that could/should look like!

We also need to consider that changes impact dataset upload, since it uses the same javascript code (and equivalent template templates/datasets/includes/dataset_files.html).