interpreter: Pass unholdered sources into BuildTarget

The build level shouldn't be deal with interpreter objects, by the time
they leave the intpreter they should be in the Meson middle layer
representaiton

mesonbuild/build.py

@@ -40,7 +40,7 @@ from .linkers import StaticLinker
 from .interpreterbase import FeatureNew
 
 if T.TYPE_CHECKING:
-    from .interpreter import Test
+    from .interpreter.interpreter import Test, SourceOutputs
     from .mesonlib import FileMode, FileOrString
     from .mesonlib.backend import Backend
 
@@ -589,12 +589,11 @@ class BuildTarget(Target):
     known_kwargs = known_build_target_kwargs
 
     def __init__(self, name: str, subdir: str, subproject: str, for_machine: MachineChoice,
-                 sources: T.List[File], objects, environment: environment.Environment, kwargs):
+                 sources: T.List['SourceOutputs'], objects, environment: environment.Environment, kwargs):
         super().__init__(name, subdir, subproject, True, for_machine)
         unity_opt = environment.coredata.get_option(OptionKey('unity'))
         self.is_unity = unity_opt == 'on' or (unity_opt == 'subprojects' and subproject != '')
         self.environment = environment
-        self.sources: T.List[File] = []
         self.compilers = OrderedDict() # type: OrderedDict[str, Compiler]
         self.objects = []
         self.external_deps = []
@@ -613,6 +612,7 @@ class BuildTarget(Target):
         self.need_install = False
         self.pch = {}
         self.extra_args: T.Dict[str, T.List['FileOrString']] = {}
+        self.sources: T.List[File] = []
         self.generated: T.Sequence[T.Union[GeneratedList, CustomTarget, CustomTargetIndex]] = []
         self.d_features = {}
         self.pic = False

mesonbuild/interpreter/interpreter.py

@@ -68,8 +68,9 @@ if T.TYPE_CHECKING:
     SourceInputs = T.Union[mesonlib.File, GeneratedListHolder, TargetHolder,
                            CustomTargetIndexHolder, GeneratedObjectsHolder, str]
     # Input source types passed to the build.Target5 classes
-    SourceOutputs = T.Union[mesonlib.File, GeneratedListHolder, TargetHolder,
-                            CustomTargetIndexHolder, GeneratedObjectsHolder]
+    SourceOutputs = T.Union[mesonlib.File, build.GeneratedList,
+                            build.BuildTarget, build.CustomTargetIndex,
+                            build.GeneratedList]
 
 def stringifyUserArguments(args, quote=False):
     if isinstance(args, list):
@@ -2705,13 +2706,16 @@ Try setting b_lundef to false instead.'''.format(self.coredata.options[OptionKey
         for s in sources:
             if isinstance(s, str):
                 self.validate_within_subproject(self.subdir, s)
-                s = mesonlib.File.from_source_file(self.environment.source_dir, self.subdir, s)
-            elif not isinstance(s, (mesonlib.File, GeneratedListHolder,
-                                    TargetHolder, CustomTargetIndexHolder,
-                                    GeneratedObjectsHolder)):
-                raise InterpreterException('Source item is {!r} instead of '
-                                           'string or File-type object'.format(s))
-            results.append(s)
+                results.append(mesonlib.File.from_source_file(self.environment.source_dir, self.subdir, s))
+            elif isinstance(s, mesonlib.File):
+                results.append(s)
+            elif isinstance(s, (GeneratedListHolder, TargetHolder,
+                                CustomTargetIndexHolder,
+                                GeneratedObjectsHolder)):
+                results.append(unholder(s))
+            else:
+                raise InterpreterException(f'Source item is {s!r} instead of '
+                                           'string or File-type object')
         return results
 
     def add_target(self, name, tobj):