[ndonkoHenri]

Three independent changes for 1.1.0.

Report Python startup errors in flet test

When the app's Python program fails before it connects, for example on an import error, flet test waited out its two-minute startup timeout and failed with only:

The following TimeoutException was thrown running a test:
The app did not load its first page within 0:02:00.000000.
...
ERROR tests/test_main.py::test_increment - RuntimeError: Flutter process exit...

The traceback was only visible in the app window, so the reporter of #7022 added a sleep to their test to read it.

The build template reports a Python program that exits early on the boot status that draws the "Error running app" screen. waitForAppLoaded (added in #6995) only checked FletBackend.error, which is set by errors that arrive over the Flet protocol, so it never saw it. It now also checks the backend's bootStatus and fails right away with the error text:

The following _Exception was thrown running a test:
Exception: The app failed to start:
Traceback (most recent call last):
  File "...\main.py", line 4, in <module>
  File "...\site-packages\pydantic\__init__.py", line 5, in <module>
  ...
ModuleNotFoundError: No module named 'pydantic_core._pydantic_core'

Tested on Windows 11 with a Flet 1.1.0 project built from source whose main.py imports pydantic (which fails there because of flet-dev/serious-python#261): without -v, the failing test prints the traceback above instead of the timeout. app_startup_test.dart gets a case for an error reported only on the boot status while the backend is still loading; all 6 tests pass.

An error raised before FletApp is built, such as a failure while the app bundle is prepared, still times out: the driver can't reach the boot status at that point.

Bump Flutter to 3.47.8

.fvmrc 3.47.7 → 3.47.8 (Dart 3.13.5 → 3.13.7, and two flutter_tools crash fixes). pub get in client, packages/flet and packages/flet_integration_test leaves every lock file unchanged. The changelog link points at #3478, which Flutter's stable changelog doesn't have a section for yet.

Type use_ref() with a function initializer

The use_ref() half of #6960, which #7014 fixed for use_state() only. use_ref(initial_value: RefValueT | Callable[[], RefValueT] | None = None) put the TypeVar on both sides of a union, so ft.use_ref(create_state) was an error in mypy (falling back to Any) and the function-or-value union in ty. Three overloads, matching the use_state() ones:

@overload
def use_ref(initial_value: None = None) -> MutableRef[Any]: ...
@overload
def use_ref(initial_value: Callable[[], RefValueT]) -> MutableRef[RefValueT]: ...
@overload
def use_ref(initial_value: RefValueT | Callable[[], RefValueT]) -> MutableRef[RefValueT]: ...

• A zero-argument function resolves to its return type: use_ref(create_state) → MutableRef[FormState].
• use_ref() and use_ref(None) give MutableRef[Any], so an empty ref can be assigned later.
• The last overload is the original signature, so custom hooks that pass a value-or-function through still type-check.

mypy, pyright and ty report 0 errors for these cases, use_state(create_state) still gives FormState, and the hook unit tests pass. The runtime is unchanged. The #6960 changelog entry now covers both hooks.

Summary by Sourcery

Improve startup failure reporting in flet test and update the bundled Flutter SDK to 3.47.8.

Bug Fixes:

• Make flet test report Python startup tracebacks immediately instead of waiting for the app startup timeout.
• Improve type inference for callable initializers passed to use_ref().
• Update the changelog to reflect the startup error reporting fix.

Enhancements:

• Update the bundled Flutter SDK to 3.47.8.

Build:

• Bump the project Flutter version from 3.47.7 to 3.47.8.

Tests:

• Add coverage for Python startup failures reported through the app boot status.

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