Add option to filter board cards by labels and assignees

[lafriks]

Works in both organization and repository project boards

Fixes #21846

Replaces #21963
Replaces #27117

Note that implementation was made intentionally to work same as in issue list so that URL can be bookmarked for quick access with predefined filters in URL

[techknowlogick]

Thanks @lafriks!! <3

I haven't tested this yet, but how does it handle the case with changing sort when some items are hidden?

[lunny]

How did you load the labels for the repository project, org project, and user projects. I think all of them are different.

• For repository project, we just need to load the labels of this repository.
• For org project, we may need to load all the labels of all repositories of this org as well as the org' labels.
• For user project, since there is no user level labels, we need to load all the labels of all repositories of this user.

[lafriks]

For labels I did:

• Repo project: Load org (if organization is owner) and repo labels (same as issue list is doing)

• Org projects: load only organization labels as adding labels for all repositories would be overkill imho and would be hard to merge same named labels from different repos together

For assignees I did:

• Repo project: all assignable users for that repo

• Org projects: all assignable users for all that organization repos

[lafriks]

I haven't tested this yet, but how does it handle the case with changing sort when some items are hidden?

It work okeyish imho, don't see anything broken

label-filter-sorting.webm

[lunny]

• Org projects: load only organization labels as adding labels for all repositories would be overkill imho and would be hard to merge same named labels from different repos together

Looks like for Org projects, since the issues on this project may also contain repository labels, how did we handle the situation?

[lafriks]

Currently in org projects you can not filter by repo only labels but that imho can be left for future improvement, mostly if you are using org projects you should be using org labels (at least if you want to filter by them in org project view) 😅

[lunny]

Currently in org projects you can not filter by repo only labels but that imho can be left for future improvement, mostly if you are using org projects you should be using org labels 😅

OK. Please add some TODO or FIXME there.

[lafriks]

@lunny added todo comment

[techknowlogick]

@lafriks amazing! Thank you so much!