structured_sources: fix subdir handling

We currently don't handle subdirectories correctly in
structured_sources, which is problematic. To make this easier to handle
correctly, I've simply changed `structured_sources` to only use Files
and not strings as an implementation detail.

mesonbuild/backend/ninjabackend.py

@@ -1669,9 +1669,7 @@ class NinjaBackend(backends.Backend):
         root = Path(self.get_target_private_dir(target)) / 'structured'
         for path, files in target.structured_sources.sources.items():
             for file in files:
-                if isinstance(file, (str, File)):
-                    if isinstance(file, str):
-                        file = File.from_absolute_file(file)
+                if isinstance(file, File):
                     out = root / path / Path(file.fname).name
                     orderdeps.append(str(out))
                     self._generate_copy_target(file, out)
@@ -1707,13 +1705,11 @@ class NinjaBackend(backends.Backend):
 
         main_rust_file = None
         if target.structured_sources:
-            if target.structured_sources.needs_copy(target):
+            if target.structured_sources.needs_copy():
                 _ods, main_rust_file = self.__generate_compile_structure(target)
                 orderdeps.extend(_ods)
             else:
                 g = target.structured_sources.first_file()
-                if isinstance(g, str):
-                    g = File.from_source_file(self.environment.source_dir, target.subdir, g)
 
                 if isinstance(g, File):
                     main_rust_file = g.rel_to_builddir(self.build_to_src)

mesonbuild/build.py

@@ -463,7 +463,7 @@ class StructuredSources(HoldableObject):
     represent the required filesystem layout.
     """
 
-    sources: T.DefaultDict[str, T.List[T.Union[str, File, CustomTarget, CustomTargetIndex, GeneratedList]]] = field(
+    sources: T.DefaultDict[str, T.List[T.Union[File, CustomTarget, CustomTargetIndex, GeneratedList]]] = field(
         default_factory=lambda: defaultdict(list))
 
     def __add__(self, other: StructuredSources) -> StructuredSources:
@@ -475,30 +475,26 @@ class StructuredSources(HoldableObject):
     def __bool__(self) -> bool:
         return bool(self.sources)
 
-    def first_file(self) -> T.Union[str, File, CustomTarget, CustomTargetIndex, GeneratedList]:
+    def first_file(self) -> T.Union[File, CustomTarget, CustomTargetIndex, GeneratedList]:
         """Get the first source in the root
 
         :return: The first source in the root
         """
         return self.sources[''][0]
 
-    def as_list(self) -> T.List[T.Union[str, File, CustomTarget, CustomTargetIndex, GeneratedList]]:
+    def as_list(self) -> T.List[T.Union[File, CustomTarget, CustomTargetIndex, GeneratedList]]:
         return list(itertools.chain.from_iterable(self.sources.values()))
 
-    def needs_copy(self, target: BuildTarget) -> bool:
+    def needs_copy(self) -> bool:
         """Do we need to create a structure in the build directory.
 
         This allows us to avoid making copies if the structures exists in the
         source dir. Which could happen in situations where a generated source
         only exists in some configurations
         """
-        p = pathlib.Path(target.subdir)
         for files in self.sources.values():
             for f in files:
-                if isinstance(f, str):
-                    if not (target.environment.source_dir / p / f).exists():
-                        return True
-                elif isinstance(f, File):
+                if isinstance(f, File):
                     if f.is_built:
                         return True
                 else:

mesonbuild/interpreter/interpreter.py

@@ -2122,11 +2122,13 @@ external dependencies (including libraries) must go to "dependencies".''')
             args: T.Tuple[object, T.Optional[T.Dict[str, object]]],
             kwargs: 'TYPE_kwargs') -> build.StructuredSources:
         valid_types = (str, mesonlib.File, build.GeneratedList, build.CustomTarget, build.CustomTargetIndex, build.GeneratedList)
-        sources: T.Dict[str, T.List[T.Union['mesonlib.FileOrString', 'build.GeneratedTypes']]] = collections.defaultdict(list)
+        sources: T.Dict[str, T.List[T.Union[mesonlib.File, 'build.GeneratedTypes']]] = collections.defaultdict(list)
 
         for arg in mesonlib.listify(args[0]):
             if not isinstance(arg, valid_types):
                 raise InvalidArguments(f'structured_sources: type "{type(arg)}" is not valid')
+            if isinstance(arg, str):
+                arg = mesonlib.File.from_source_file(self.environment.source_dir, self.subdir, arg)
             sources[''].append(arg)
         if args[1]:
             if '' in args[1]:
@@ -2135,6 +2137,8 @@ external dependencies (including libraries) must go to "dependencies".''')
                 for arg in mesonlib.listify(v):
                     if not isinstance(arg, valid_types):
                         raise InvalidArguments(f'structured_sources: type "{type(arg)}" is not valid')
+                    if isinstance(arg, str):
+                        arg = mesonlib.File.from_source_file(self.environment.source_dir, self.subdir, arg)
                     sources[k].append(arg)
         return build.StructuredSources(sources)