Ipynb widget parity - #742

The namespace from runpy.run_path is discarded, so widgets created by
an example are garbage-collected at an arbitrary later point during
event processing.  A still-visible widget whose C++ side is deleted
mid-event-loop can receive a paintEvent during deletion, which PyQt5
escalates to a process abort:

    RuntimeError: wrapped C/C++ object of type QRangeSlider has been
    deleted

as seen intermittently on the windows-latest (3.12) pyqt5 job in
test_example[demo_widgets/range_slider.py] (e.g. the scheduled main
run on 2026-08-22, and both pyapp-kit#741 and pyapp-kit#742).

Close (hide) all top-level widgets first so nothing can paint, then
deleteLater() + sendPostedEvents(None, DeferredDelete) to destroy the
native widgets (and stop their timers) while hidden -- note that
processEvents() alone does NOT dispatch DeferredDelete events -- then
gc.collect() for anything left over.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The namespace from runpy.run_path is discarded, so widgets created by
an example are garbage-collected at an arbitrary later point during
event processing.  A still-visible widget whose C++ side is deleted
mid-event-loop can receive a paintEvent during deletion, which PyQt5
escalates to a process abort:

    RuntimeError: wrapped C/C++ object of type QRangeSlider has been
    deleted

as seen intermittently on the windows-latest (3.12) pyqt5 job in
test_example[demo_widgets/range_slider.py] (e.g. the scheduled main
run on 2026-08-22, and both pyapp-kit#741 and pyapp-kit#742).

Close (hide) all top-level widgets first so nothing can paint, then
deleteLater() + sendPostedEvents(None, DeferredDelete) to destroy the
native widgets (and stop their timers) while hidden -- note that
processEvents() alone does NOT dispatch DeferredDelete events -- then
gc.collect() for anything left over.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* test: deterministically tear down example widgets

The namespace from runpy.run_path is discarded, so widgets created by
an example are garbage-collected at an arbitrary later point during
event processing.  A still-visible widget whose C++ side is deleted
mid-event-loop can receive a paintEvent during deletion, which PyQt5
escalates to a process abort:

    RuntimeError: wrapped C/C++ object of type QRangeSlider has been
    deleted

as seen intermittently on the windows-latest (3.12) pyqt5 job in
test_example[demo_widgets/range_slider.py] (e.g. the scheduled main
run on 2026-08-22, and both #741 and #742).

Close (hide) all top-level widgets first so nothing can paint, then
deleteLater() + sendPostedEvents(None, DeferredDelete) to destroy the
native widgets (and stop their timers) while hidden -- note that
processEvents() alone does NOT dispatch DeferredDelete events -- then
gc.collect() for anything left over.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* test: allow pytest-qt >=4.5 everywhere except PySide2

pytest-qt 4.4.0 is incompatible with recent PySide6: qtbot.waitSignal
fails with 'SystemError: <method disconnect of SignalInstance> returned
a result with an exception set' and a TimeoutError in
test_parent_changed (reproduced locally with PySide6 6.11.2 +
pytest-qt 4.4.0; fixed by pytest-qt 4.5.0, see pytest-dev/pytest-qt#552).
This is what has been failing every pyside6 CI job (and the scheduled
runs on main) since at least mid-July.

pytest-qt 4.5 dropped PySide2, so the pyside2 dependency group keeps
the 4.4.0 pin via a separate test-qt-legacy group, declared as a uv
conflict so universal resolution still succeeds.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* build: emit core metadata 2.4 until twine accepts 2.5

hatchling 1.32.0 (2026-08-11) bumped the default core metadata version
to 2.5, which the twine run by build-and-inspect-python-package rejects
('InvalidDistribution: 2.5 is not a valid metadata version').  Nobody
noticed because build-and-inspect needs the test job, which has been
red since mid-July (see previous commit).  Verified locally: with this
setting both the wheel and sdist emit Metadata-Version 2.4 and pass
'twine check --strict'.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* style(pre-commit.ci): auto fixes [...]

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Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

UP035 under the new py311 target. #742 merged after #745 switched
target-version, so its CI ran against the old config and main is
currently failing ruff.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix: handle PEP 604 unions (`X | Y`) like `Union[X, Y]`

`get_origin(int | None)` is `types.UnionType`, not `typing.Union`, on
python < 3.14 -- so the four `get_origin(...) is Union` comparisons
silently took the non-union path for PEP 604 annotations.

Most visibly, the Optional wrapper was not stripped from a widget's
reported annotation:

    @magicgui
    def f(x: Optional[int] = None): ...   # .annotation -> int
    @magicgui
    def f(x: int | None = None): ...      # .annotation -> int | None

and `register_type(int | str, return_callback=...)` registered nothing
for the individual member types.

Adds `magicgui._util.is_union`, which accepts both spellings, and uses
it at all four sites.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* style: import Callable from collections.abc in the ipynb backend

UP035 under the new py311 target. #742 merged after #745 switched
target-version, so its CI ran against the old config and main is
currently failing ruff.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* style: enable UP045 for source now that PEP 604 unions work

The preceding fix makes `X | None` behave like `Optional[X]`, so the
pyupgrade rewrite is safe for src. Scoped deliberately:

- UP045 is enabled for src/ and docs/ only; tests/ keep it ignored,
  since they exercise both spellings on purpose (see test_no_order).
- UP007 stays ignored: `Union` is still needed as a runtime *value* for
  the public type aliases (PathLike, ChoicesType, AppRef, TableData,
  WidgetRef) and for `Union[args]` construction. ruff offers no fix for
  those 11 sites, so enabling it would just leave permanent errors.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 5 <noreply@anthropic.com>