🐛 fixed the slug generator to not allow single character slugs

[cathysarisky]

closes #20133 and masks the effects of TryGhost/NQL#20

It is currently possible to create a user, tag, post, etc with a single character slug.
(It is far too easy to do this with users, if your users have names like C. Ann Smythe.)

Single character slugs break things. They break displaying the posts of a user with a single character slug, and displaying posts with a single-character tag slug, and so on.

Since fixing the underlying NQL parser glitch isn't an easy option, this patch tweaks the logic for generating slugs by
(1) not truncating user names during user creating before the second character (so C. Ann Smythe becomes c-ann instead of c)
(2) checking late in the process for single character slugs, and changing them to baseName-slug, such that a post with title 'q' becomes 'post-q', and a user requesting a change to their slug to the slug 't' will be 'user-t' instead, or if they're new and we are generating the slug from their name, they'll be user-t if their whole name is 'T', or t-lastname if there's more to work with.

The one spot where I feel like this could be improved is user-requested slugs from the profile, where slug generation happens on clicking save (I think), rather than the field updating live like the it does with post slugs.

[9larsons]

Could you elaborate a bit on what troubles are caused w/in NQL?

[cathysarisky]

Could you elaborate a bit on what troubles are caused w/in NQL?

Yep. Filtering with single character strings doesn't work. See #20133 and TryGhost/NQL#20

[ErisDS]

Honestly, I thought we fixed the NQL issue ages ago 😢
Wondering if it regressed or if I have lost the actual plot 🤔

[cathysarisky]

It’s still there! Confirmed prior to filing the PR.

[9larsons]

I've just merged TryGhost/NQL@07cc8c1 so I'll bump NQL and make sure that all passed ok.

Going to close this one out 🙂.