cargo: raw.Manifest can be any Cargo.toml

raw.Manifest represents any Cargo.toml file, a package, a workspace, or
both.

However, the Manifest dataclass can only be a package, and the Workspace
dataclass is a workspace with an optional root package.

3 files changed, 12 insertions, 32 deletions

diff --git a/mesonbuild/cargo/interpreter.py b/mesonbuild/cargo/interpreter.py
index c763483dd..818e8640b 100644
--- a/mesonbuild/cargo/interpreter.py
+++ b/mesonbuild/cargo/interpreter.py
@@ -304,23 +304,13 @@ class Interpreter:
             path = os.path.join(self.environment.source_dir, subdir)
             filename = os.path.join(path, 'Cargo.toml')
             self.build_def_files.append(filename)
-            toml = load_toml(filename)
-            workspace_ = None
-            if 'workspace' in toml:
-                raw_workspace = T.cast('raw.VirtualManifest', toml)
-                workspace_ = Workspace.from_raw(raw_workspace)
-            manifest_ = None
-            if 'package' in toml:
-                raw_manifest = T.cast('raw.Manifest', toml)
+            raw_manifest = T.cast('raw.Manifest', load_toml(filename))
+            if 'workspace' in raw_manifest:
+                manifest_ = Workspace.from_raw(raw_manifest, path)
+            elif 'package' in raw_manifest:
                 manifest_ = Manifest.from_raw(raw_manifest, path, workspace, member_path)
-            if not manifest_ and not workspace_:
+            else:
                 raise MesonException(f'{subdir}/Cargo.toml does not have [package] or [workspace] section')
-
-            if workspace_:
-                workspace_.root_package = manifest_
-                self.manifests[subdir] = workspace_
-                return workspace_
-
             self.manifests[subdir] = manifest_
         return manifest_
 
diff --git a/mesonbuild/cargo/manifest.py b/mesonbuild/cargo/manifest.py
index d3d036769..9dadcd8a7 100644
--- a/mesonbuild/cargo/manifest.py
+++ b/mesonbuild/cargo/manifest.py
@@ -481,13 +481,14 @@ class Workspace:
     metadata: T.Dict[str, T.Any] = dataclasses.field(default_factory=dict)
 
     # A workspace can also have a root package.
-    root_package: T.Optional[Manifest] = dataclasses.field(init=False)
+    root_package: T.Optional[Manifest] = None
 
     @classmethod
-    def from_raw(cls, raw: raw.VirtualManifest) -> Workspace:
-        ws_raw = raw['workspace']
-        fixed = _raw_to_dataclass(ws_raw, cls, 'Workspace')
-        return fixed
+    def from_raw(cls, raw: raw.Manifest, path: str) -> Workspace:
+        ws = _raw_to_dataclass(raw['workspace'], cls, 'Workspace')
+        if 'package' in raw:
+            ws.root_package = Manifest.from_raw(raw, path, ws, '.')
+        return ws
 
 
 @dataclasses.dataclass
diff --git a/mesonbuild/cargo/raw.py b/mesonbuild/cargo/raw.py
index 67dd58a9f..801f9a568 100644
--- a/mesonbuild/cargo/raw.py
+++ b/mesonbuild/cargo/raw.py
@@ -140,7 +140,7 @@ class Workspace(TypedDict):
 Manifest = TypedDict(
     'Manifest',
     {
-        'package': Required[Package],
+        'package': Package,
         'badges': T.Dict[str, Badge],
         'dependencies': T.Dict[str, T.Union[FromWorkspace, DependencyV]],
         'dev-dependencies': T.Dict[str, T.Union[FromWorkspace, DependencyV]],
@@ -162,17 +162,6 @@ Manifest = TypedDict(
 """The Cargo Manifest format."""
 
 
-class VirtualManifest(TypedDict, total=False):
-
-    """The Representation of a virtual manifest.
-
-    Cargo allows a root manifest that contains only a workspace, this is called
-    a virtual manifest. This doesn't really map 1:1 with any meson concept,
-    except perhaps the proposed "meta project".
-    """
-
-    workspace: Workspace
-
 class CargoLockPackage(TypedDict, total=False):
 
     """A description of a package in the Cargo.lock file format."""