Implement DictionaryPropertyEdit .

[jagt]

This PR implements DictionaryPropertyEdit for editting exported dictionary properties (#10018).
Here's a screenshot:

However there're some usability issues which I really need some help from you guys:

1. Changing the size field won't work atm as I don't see a way for this to work for a dictionary. So currently there's no way to add/remove new items through the inspector. I think the most common way to handle this is to add a button/widget to add new items, but I don't find a way to add button in inspector/.
2. Can't handle duplicated keys. If one change a key to be equal to a existing key, the dictionary will actually shrink the dictionary by one. I don't really know how to handle this through the UI. Should duplicate key changes be ignored or report a error? Or I should simply make keys readonly.
3. Changing keys will change item order. Maybe this can be fixed by adding data to track item orders.

Most of the problems are related to key editing. Your input on this will be really helpful.

[akien-mga]

There's a slight style issue with the ordering of the includes (it should be alphabetical), could you amend the commit to fix it? https://travis-ci.org/godotengine/godot/jobs/286360431

[Geequlim]

I don't think it is a good idea to show 4 rows in the inspector for each element of a dictionary.

[djrm]

that interface seems very complicated for a simple task, maybe it would be better to wait until the inspector gets rewritten.

[jagt]

IMO I can't find a way to implement a usable Dictionary inspector atm. If there's plan to rewrite inspector then maybe this should be postponed after that is done.
Is there any discussion about the rewrite? Thanks!

[djrm]

@jagt the rewrite is planned for 3.1, so it might be better to wait after the release of 3 to discuss this

[jagt]

@djrm ok. I'm closing this for now.

[bojidar-bg]

Reopening as per discussion with reduz on IRC (click to expand)

‎‎<‎bojidar_bg‎>‎ … -- the PR got closed as the interface was "too complex"
‎‎<‎bojidar_bg‎>‎ and set to wait for inspector redesigning in 3.1
‎‎<‎reduz‎>‎ it should still work
‎‎<‎reduz‎>‎ actually
‎‎<‎reduz‎>‎ but most of the points raised are valid
‎‎<‎bojidar_bg‎>‎ I guess we might get it reopened and merged as a workaround
‎‎<‎bojidar_bg‎>‎ and fix it up later on, maybe even for a 3.0.1, in case there is a way
‎‎<‎reduz‎>‎ the order issue is solved by #12656 karroffel just PRd
‎‎<‎reduz‎>‎ i would also not expose size, simply in the type enum, an extra option "Delete" could be added
‎‎<‎reduz‎>‎ for duplicate keys, that's just life
‎‎<‎bojidar_bg‎>‎ sounds good
‎‎<‎reduz‎>‎ the only use case i'm not completely sure is adding new keys
‎‎<‎bojidar_bg‎>‎ we might rename the duplicate key, similar to how duplicate node names are renamed
‎‎<‎bojidar_bg‎>‎ reduz: there might be an empty entry at the end of the dictionary
‎‎<‎reduz‎>‎ bojidar_bg: oh that makes sense

---

The main points from the discussion are:

• Order is fixed by make Dictionary use OrderedHashMap #12656 (which is likely to merged soon-ish).
• Size should be replaced by a "Delete" type of keys and/or value (when selected, removes the key/value from the dictionary).
• To add new key/value pairs, there should be a key with "Delete" type below all the others.
• Duplicate keys might (or might not) be renamed similar to how nodes are currently renamed (if strings)

[Geequlim]

I did the same thing in #11940 it is designed to display remote dictionaries so it doesn't implement too much features as @bojidar-bg said.

[akien-mga]

Superseded by #11940 which we are soon going to merge, but thanks a lot for the proposal, it helped with the design of how we want it to be.