Tags suggestion list is broken

[marcingajda]

Adding existing tags makes them display as slugs instead of names.
Probably a regression after #7822.

Details

Question	Answer
Relevant Bolt Version	3.7
Install type	Composer install
BC Break	yes?
PHP version	7.3
Web server	Nginx (latest)
For UX/UI issues	Chrome

Reproduction

Bug summary

After selecting an existing tag from the select suggestion list it is saved in the database with the slug in the place of name. After that Bolt displays tags slugs instead of full names. Adding new tags works fine.

Steps to reproduce

1. Create a content type eg.: articles with tags taxonomy like this

tags:
    slug: tags
    singular_slug: tag
    behaves_like: tags
    postfix: "Add some freeform tags. Start a new tag by typing a comma or space."
    allow_spaces: true
    listing_template: "tags.twig"
    options: {}

2. Edit a record of this content type eg.: http://example.com/bolt/editcontent/articles/123
3. Go to the tags selector and add a brand new tag like "Foo Bar"
   
4. Save the article and observe the Network tab in Chrome inspector to see that the tag is send properly
   
5. Refresh the editor and see that the tag looks good:
   
6. Edit a second article eg.: http://example.com/bolt/editcontent/articles/789
7. Go to tags select and choose the same tag but from suggestion list
   
8. Save the article and see in the Network inspector that this time the tag is send as a slug:
   
9. Refresh the editor to discover that the tag displays in the select as slug
   
10. The same happens on the frontend
    

Expected result

Tags should be always displayed with the original name

Actual result

After selecting a suggested tag it displays as a slug.
In the database it's also saved with incorrect name:

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Maybe this issue has been fixed in a recent release, or perhaps it is not affecting a lot of people?
It will be closed if no further activity occurs, because we like to keep the issue queue concise and actual.
If you think this issue is still relevant, please let us know. Especially if you’d like to help resolve the issue, either by helping us pinpointing the cause of a bug, or in implementing a fix or new feature.

[decemberly]

I'm also having this issue in Bolt 3.7.

[hannesl]

Same issue here.

Yes, #7822 is probably the culprit. That PR changed the article form to identify tags using their slugs rather than their names, which is probably a good idea, but somewhere there is some code that wasn't updated to reflect this. Another challenge is that new tags don't have a slug until they're saved, which is probably the reason why names were used instead of slugs to begin with.