Call into operations.generate_metadata to generate metadata

src/pip/_internal/operations/generate_metadata.py

@@ -0,0 +1,26 @@
+"""Metadata generation logic for source distributions.
+"""
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Callable
+    from pip._internal.req.req_install import InstallRequirement
+
+
+def get_metadata_generator(install_req):
+    # type: (InstallRequirement) -> Callable[[InstallRequirement], None]
+    if not install_req.use_pep517:
+        return _generate_metadata_legacy
+
+    return _generate_metadata
+
+
+def _generate_metadata_legacy(install_req):
+    # type: (InstallRequirement) -> None
+    install_req.run_egg_info()
+
+
+def _generate_metadata(install_req):
+    # type: (InstallRequirement) -> None
+    install_req.prepare_pep517_metadata()

src/pip/_internal/req/req_install.py

@@ -23,6 +23,7 @@
 from pip._internal.build_env import NoOpBuildEnvironment
 from pip._internal.exceptions import InstallationError
 from pip._internal.models.link import Link
+from pip._internal.operations.generate_metadata import get_metadata_generator
 from pip._internal.pyproject import load_pyproject_toml, make_pyproject_path
 from pip._internal.req.req_uninstall import UninstallPathSet
 from pip._internal.utils.compat import native_str
@@ -559,11 +560,9 @@ def prepare_metadata(self):
         """
         assert self.source_dir
 
+        metadata_generator = get_metadata_generator(self)
         with indent_log():
-            if self.use_pep517:
-                self.prepare_pep517_metadata()
-            else:
-                self.run_egg_info()
+            metadata_generator(self)
 
         if not self.req:
             if isinstance(parse_version(self.metadata["Version"]), Version):