modules/qt: allow passing generated targets to compile_ui

docs/markdown/_include_qt_base.md

@@ -21,8 +21,9 @@ It takes no positional arguments, and the following keyword arguments:
 Compiles Qt's ui files (.ui) into header files.
 
 It takes no positional arguments, and the following keyword arguments:
-  - `sources` (File | string)[]: A list of sources to be transpiled. Required,
-    must have at least one source
+  - `sources` (File | string | custom_target | custom_target index | generator_output)[]:
+    A list of sources to be transpiled. Required, must have at least one source
+    *New in 0.60.0*: support for custom_target, custom_target_index, and generator_output.
   - `extra_args` string[]: Extra arguments to pass directly to `qt-uic`
   - `method` string: The method to use to detect qt, see `dependency()` for more
     information.

mesonbuild/modules/qt.py

@@ -52,7 +52,7 @@ if T.TYPE_CHECKING:
 
         """Keyword arguments for the Ui Compiler method."""
 
-        sources: T.Sequence[T.Union[FileOrString, build.CustomTarget]]
+        sources: T.Sequence[T.Union[FileOrString, build.CustomTarget, build.CustomTargetIndex, build.GeneratedList]]
         extra_args: T.List[str]
         method: str
 
@@ -337,12 +337,19 @@ class QtBaseModule(ExtensionModule):
     @noPosargs
     @typed_kwargs(
         'qt.compile_ui',
-        KwargInfo('sources', ContainerTypeInfo(list, (File, str), allow_empty=False), listify=True, required=True),
+        KwargInfo(
+            'sources',
+            ContainerTypeInfo(list, (File, str, build.CustomTarget, build.CustomTargetIndex, build.GeneratedList), allow_empty=False),
+            listify=True,
+            required=True,
+        ),
         KwargInfo('extra_args', ContainerTypeInfo(list, str), listify=True, default=[]),
         KwargInfo('method', str, default='auto')
     )
     def compile_ui(self, state: 'ModuleState', args: T.Tuple, kwargs: 'UICompilerKwArgs') -> ModuleReturnValue:
         """Compile UI resources into cpp headers."""
+        if any(isinstance(s, (build.CustomTarget, build.CustomTargetIndex, build.GeneratedList)) for s in kwargs['sources']):
+            FeatureNew.single_use('qt.compile_ui: custom_target or generator for "sources" keyword argument', '0.60.0', state.subproject)
         out = self._compile_ui_impl(state, kwargs)
         return ModuleReturnValue(out, [out])