Corpus form: corpora with no sample file

The corpus form is structured so users must upload a (sample) CSV data file first; that becomes the basis for the fields form.

However, there are other routes to create database-only corpora without a CSV file. You can create corpora through the admin menu, or remove the Python definition for a corpus to make it database-only. (Python corpora don't have sample files.)

The corpus form handles this situation awkwardly; it's not presenting the situation clearly to the user.

An easy and acceptable solution would be to block such corpora from being editable in the frontend. The other solution would be to let the form gracefully handle this situation in some way or another. Either is fine, not sure which would be easier.

Start by tracing the frontend corpus form and reproducing the issue with a database-only corpus created through the admin menu or without a Python definition. Decide whether to block editing or handle the missing sample file gracefully, then verify that the user-facing behavior clearly explains the situation.

Written by the indexing model from the issue text.