We need to decide what to do when FileImporter is used to import an uncategorized file. Currently, the code will do nothing special, and will happily import the file.
Some behaviors we might want to adopt:
- Show a warning box on the preview page when importing, saying "Please consider adding categories after import".
- More humble warning stating the above, but without an infobox.
- Add a configurable snippet of wikitext to the file info during preview, and during actual import. This could default to empty, but would probably be set to {{subst:unc}} on commonswiki.
- Ask for confirmation when importing an uncategorized file, in an additional step.
If we want to replicate UploadWizard functionality, I believe it does (3) and (4).