MAINT: streamline project metadata handling some more

To support "dependencies" as a dynamic filed in pyproject.toml and
implement build time dependencies pins we need to rewrite this part of
the metadata in the wheel builder. Move the RFC 822 serialization of
the metadata closer to where it is written to the wheel archive.

Author: dnicolodi

mesonpy/__init__.py

@@ -192,15 +192,13 @@ class _WheelBuilder():
     def __init__(
         self,
         project: Project,
-        metadata: Optional[pyproject_metadata.StandardMetadata],
         source_dir: pathlib.Path,
         install_dir: pathlib.Path,
         build_dir: pathlib.Path,
         sources: Dict[str, Dict[str, Any]],
         copy_files: Dict[str, str],
     ) -> None:
         self._project = project
-        self._metadata = metadata
         self._source_dir = source_dir
         self._install_dir = install_dir
         self._build_dir = build_dir
@@ -293,13 +291,13 @@ def wheel(self) -> bytes:
     @property
     def entrypoints_txt(self) -> bytes:
         """dist-info entry_points.txt."""
-        if not self._metadata:
+        if not self._project.metadata:
             return b''
 
-        data = self._metadata.entrypoints.copy()
+        data = self._project.metadata.entrypoints.copy()
         data.update({
-            'console_scripts': self._metadata.scripts,
-            'gui_scripts': self._metadata.gui_scripts,
+            'console_scripts': self._project.metadata.scripts,
+            'gui_scripts': self._project.metadata.gui_scripts,
         })
 
         text = ''
@@ -553,7 +551,7 @@ def _install_path(
 
     def _wheel_write_metadata(self, whl: mesonpy._wheelfile.WheelFile) -> None:
         # add metadata
-        whl.writestr(f'{self.distinfo_dir}/METADATA', self._project.metadata)
+        whl.writestr(f'{self.distinfo_dir}/METADATA', bytes(self._project.metadata.as_rfc822()))
         whl.writestr(f'{self.distinfo_dir}/WHEEL', self.wheel)
         if self.entrypoints_txt:
             whl.writestr(f'{self.distinfo_dir}/entry_points.txt', self.entrypoints_txt)
@@ -894,7 +892,6 @@ def _validate_metadata(self) -> None:
     def _wheel_builder(self) -> _WheelBuilder:
         return _WheelBuilder(
             self,
-            self._metadata,
             self._source_dir,
             self._install_dir,
             self._build_dir,
@@ -1002,10 +999,10 @@ def version(self) -> str:
         """Project version."""
         return str(self._metadata.version)
 
-    @cached_property
-    def metadata(self) -> bytes:
-        """Project metadata as an RFC822 message."""
-        return bytes(self._metadata.as_rfc822())
+    @property
+    def metadata(self) -> pyproject_metadata.StandardMetadata:
+        """Project metadata."""
+        return self._metadata
 
     @property
     def license_file(self) -> Optional[pathlib.Path]:
@@ -1075,8 +1072,9 @@ def sdist(self, directory: Path) -> pathlib.Path:
             pkginfo_info = tarfile.TarInfo(f'{dist_name}/PKG-INFO')
             if mtime:
                 pkginfo_info.mtime = mtime
-            pkginfo_info.size = len(self.metadata)
-            tar.addfile(pkginfo_info, fileobj=io.BytesIO(self.metadata))
+            metadata = bytes(self._metadata.as_rfc822())
+            pkginfo_info.size = len(metadata)
+            tar.addfile(pkginfo_info, fileobj=io.BytesIO(metadata))
 
         return sdist
 

tests/test_tags.py

@@ -56,7 +56,7 @@ def wheel_builder_test_factory(monkeypatch, content):
     files = defaultdict(list)
     files.update({key: [(pathlib.Path(x), os.path.join('build', x)) for x in value] for key, value in content.items()})
     monkeypatch.setattr(mesonpy._WheelBuilder, '_wheel_files', files)
-    return mesonpy._WheelBuilder(None, None, pathlib.Path(), pathlib.Path(), pathlib.Path(), pathlib.Path(), pathlib.Path())
+    return mesonpy._WheelBuilder(None, pathlib.Path(), pathlib.Path(), pathlib.Path(), {}, {})
 
 
 def test_tag_empty_wheel(monkeypatch):