Steps to reproduce

In DropdownMenuFormField's constructor, we invoke super (which is of type FormField) with a builder that declares the onSelectedHandler function, closing over _DropdownMenuFormFieldState<T>'s didChange:

... and later uses it in the constructor of DropdownMenu:

For reference, here is the declaration (on _DropdownMenuFormFieldState) of didChange:

Note that didChange invokes _dropdownMenuFormField.onSelected?.call(value). Note that onSelectedHandler (linked above), first invokes didChange, then itself invokes onSelected?.call(value).

As a result, the original final ValueChanged<T?>? onSelected; passed in via constructor argument below to DropdownMenuFormField is double-invoked.

Expected results

onSelected is invoked once when a DropdownMenuEntry is selected within a DropdownMenuFormField.

Actual results

onSelected is invoked twice when a DropdownMenuEntry is selected within a DropdownMenuFormField.

Code sample

N/A

Screenshots or Video

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Logs

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Flutter Doctor output

[!] Flutter (Channel stable, 3.35.1, on macOS 15.6 24G84 darwin-arm64, locale en-US)