feat: Register all types in a Union when passed to return_callback

[tlambert03]

part of a fix to #541, this makes it so that when you use register_type(Union[...], return_callback=...), then you effectively register the callback for functions that return either the union or any type within the Union (not just the actual union object itself)

[codecov]

Codecov Report

Patch coverage: 92.00% and project coverage change: +0.09 🎉

Comparison is base (c5f7a13) 89.66% compared to head (3d64e5f) 89.75%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #544      +/-   ##
==========================================
+ Coverage   89.66%   89.75%   +0.09%     
==========================================
  Files          37       37              
  Lines        4423     4433      +10     
==========================================
+ Hits         3966     3979      +13     
+ Misses        457      454       -3     

Impacted Files	Coverage Δ
src/magicgui/type_map/_type_map.py	96.41% <92.00%> (+0.16%)	⬆️

... and 1 file with indirect coverage changes

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[tlambert03]

cc @Czaki, if you have a moment to review, this implements option 3 from #541 (comment)

[Czaki]

I do not see documentation update, but I assume that it is connected with plan to remove return callback?

Also, in the context of napari:

Currently problem is solved in this way (main only, not released):
https://github.com/napari/napari/blob/9e911040148d232b76d768ed74ff90ac0fa6f707/napari/types.py#L145
https://github.com/napari/napari/blob/9e911040148d232b76d768ed74ff90ac0fa6f707/napari/types.py#L158

But code in magicgui does not contain deduplication of callbacks.

So I understand that After merging it there should be added if to napari codebase to check it depends on the magicgui version?

[tlambert03]

So I understand that After merging it there should be added if to napari codebase to check it depends on the magicgui version?

yeah, I can do that PR if you'd like?

[tlambert03]

updated the docs a bit. thanks for the review @Czaki !

[tlambert03]

But code in magicgui does not contain deduplication of callbacks.

this is a good point... but i think in most cases it's going to be fine (the second one will overwrite the first one). let me double check that for you

[Czaki]

this is a good point... but i think in most cases it's going to be fine (the second one will overwrite the first one). let me double check that for you

Yes and the whole recalculation of all attributes and double transfer to GPU memory of layer data?

[tlambert03]

Yes and the whole recalculation of all attributes and double transfer to GPU memory of layer data?

no, I don't mean the second "layer" will overwrite the first "layer", I mean the second registered callback will overwrite the first registered callback (in the type2callback map) and only a single one will actually be called at runtime

[tlambert03]

buuut nope... it gets called twice. will fix