Nested containers

[ndxmrb]

Hi @tlambert03,
restarting my work from #669 after the ValuedContainer changes.

Still, some things are missing:

• Proper test e.g. for getting nested values from ValueWidgets and ContainerWidgets. Does this belong to test_pydantic()in test_ui_field.py?
• QGroupBox option as mentioned in Improve nesting of containers with labels (group box) #317

Tried my best with the types again, hope it's okay that way.

Thanks for having a look!

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.13%. Comparing base (45a54d1) to head (5ab31e5).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/magicgui/schema/_ui_field.py	57.89%	8 Missing ⚠️
src/magicgui/widgets/bases/_container_widget.py	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #704      +/-   ##
==========================================
- Coverage   89.28%   89.13%   -0.16%     
==========================================
  Files          40       40              
  Lines        4816     4841      +25     
==========================================
+ Hits         4300     4315      +15     
- Misses        516      526      +10     

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[tlambert03]

hey @ndxmrb

so sorry for the long delay. couple concerns about typing and error catching. we don't need to belabor them too much, if you can fix great, otherwise let me know.

[tlambert03]

I would prefer to avoid functions that return unions if at all possible. Isn't a NestedValueWidget ultimately also just a ValueWidget? Doesn't it have teh same interface? Is there anything in the PR here that actually requires a new type? Can we revert these NestedValueWidget changes without mypy breaking?

[ndxmrb]

I created that just to make mypy happy. But I agree not having unions is better.
Looking at QuantityEdit for pint.Quantity - which is a ValueWidget, yes it should be a ValueWidget, too. On the other hand we now have ValuedContainerWidget e.g. for tuples, so maybe it should rather be that?

[tlambert03]

I think this except ValueError is something I did elsewhere at one point (right?) but I don't really like it since it's rather indirect. Unless we're certain that ValueError and TypeErrors are only ever raised for the specific cases that we are catching here, I'd prefer to do some look-before-you-leap pattern instead. (At the very least, I'd like to ensure that self.type is a valid dataclass-like object before calling build_widget on it).

[ndxmrb]

Yes, I just got that from here. I had to modify asdict() as well, it didn't run out-of-the-box when using the values.

I'm now checking for dataclass-likeness. Could you elaborate how I can make sure that it's valid?