Various cleanups prompted by Benjy's review.

pex/finders.py

@@ -9,9 +9,9 @@
 from pex.common import is_python_script, open_zip, safe_mkdtemp
 from pex.dist_metadata import Distribution, DistributionType, EntryPoint
 from pex.pep_376 import InstalledWheel
-from pex.pep_427 import Wheel
 from pex.pep_503 import ProjectName
 from pex.typing import TYPE_CHECKING, cast
+from pex.wheel import Wheel
 
 if TYPE_CHECKING:
     from typing import Dict, Iterable, Optional

pex/pep_376.py

@@ -19,7 +19,7 @@
 from pex.typing import TYPE_CHECKING, cast
 from pex.util import CacheHelper
 from pex.venv.virtualenv import Virtualenv
-from pex.wheel import WHEEL
+from pex.wheel import WHEEL, WheelMetadataLoadError
 
 if TYPE_CHECKING:
     from typing import Callable, Iterable, Iterator, Optional, Protocol, Text, Tuple, Union
@@ -142,20 +142,11 @@ def denormalized_path(
     size = attr.ib(default=None)  # type: Optional[int]
 
 
-class InstalledWheelError(Exception):
-    pass
-
-
-class LoadError(InstalledWheelError):
-    """Indicates an installed wheel was not loadable at a particular path."""
-
-
-class ReinstallError(InstalledWheelError):
-    """Indicates an error re-installing an installed wheel."""
-
-
 @attr.s(frozen=True)
 class InstalledWheel(object):
+    class LoadError(Exception):
+        """Indicates an installed wheel was not loadable at a particular path."""
+
     _LAYOUT_JSON_FILENAME = ".layout.json"
 
     @classmethod
@@ -201,20 +192,20 @@ def load(cls, prefix_dir):
             with open(layout_file) as fp:
                 layout = json.load(fp)
         except (IOError, OSError) as e:
-            raise LoadError(
+            raise cls.LoadError(
                 "Failed to load an installed wheel layout from {layout_file}: {err}".format(
                     layout_file=layout_file, err=e
                 )
             )
         if not isinstance(layout, dict):
-            raise LoadError(
+            raise cls.LoadError(
                 "The installed wheel layout file at {layout_file} must contain a single top-level "
                 "object, found: {value}.".format(layout_file=layout_file, value=layout)
             )
         stash_dir = layout.get("stash_dir")
         record_relpath = layout.get("record_relpath")
         if not stash_dir or not record_relpath:
-            raise LoadError(
+            raise cls.LoadError(
                 "The installed wheel layout file at {layout_file} must contain an object with both "
                 "`stash_dir` and `record_relpath` attributes, found: {value}".format(
                     layout_file=layout_file, value=layout
@@ -226,11 +217,11 @@ def load(cls, prefix_dir):
         # N.B.: Caching root_is_purelib was not part of the original InstalledWheel layout data; so
         # we materialize the property if needed to support older installed wheel chroots.
         root_is_purelib = layout.get("root_is_purelib")
-        if type(root_is_purelib) is not bool:
+        if root_is_purelib is None:
             try:
                 wheel = WHEEL.load(prefix_dir)
-            except WHEEL.LoadError as e:
-                raise LoadError(
+            except WheelMetadataLoadError as e:
+                raise cls.LoadError(
                     "Failed to determine if installed wheel at {location} is platform-specific: "
                     "{err}".format(location=prefix_dir, err=e)
                 )

pex/pep_427.py

@@ -16,13 +16,13 @@
 from pex import pex_warnings
 from pex.common import chmod_plus_x, is_pyc_file, iter_copytree, open_zip, safe_open, touch
 from pex.compatibility import commonpath, get_stdout_bytes_buffer
-from pex.dist_metadata import DistMetadata, Distribution, MetadataFiles, ProjectNameAndVersion
+from pex.dist_metadata import Distribution, ProjectNameAndVersion
 from pex.enum import Enum
 from pex.interpreter import PythonInterpreter
 from pex.pep_376 import InstalledFile, InstalledWheel, Record
 from pex.pep_503 import ProjectName
 from pex.typing import TYPE_CHECKING, cast
-from pex.wheel import WHEEL
+from pex.wheel import Wheel
 
 if TYPE_CHECKING:
     from typing import (  # noqa
@@ -158,76 +158,6 @@ def install_wheel_interpreter(
     )
 
 
-class WheelLoadError(WheelError):
-    """Indicates loading a wheel from disk."""
-
-
-@attr.s(frozen=True)
-class Wheel(object):
-    @classmethod
-    def load(cls, wheel_path):
-        # type: (str) -> Wheel
-
-        try:
-            metadata = WHEEL.load(wheel_path)
-        except WHEEL.LoadError as e:
-            raise WheelLoadError(str(e))
-
-        metadata_path = metadata.files.metadata_file_rel_path("WHEEL")
-        if not metadata_path:
-            raise WheelLoadError(
-                "Could not find WHEEL metadata in {wheel}.".format(wheel=wheel_path)
-            )
-
-        wheel_metadata_dir = os.path.dirname(metadata_path)
-        if not wheel_metadata_dir.endswith(".dist-info"):
-            raise WheelLoadError(
-                "Expected WHEEL metadata for {wheel} to be housed in a .dist-info directory, but was "
-                "found at {wheel_metadata_path}.".format(
-                    wheel=wheel_path, wheel_metadata_path=metadata_path
-                )
-            )
-        # Although not crisply defined, all PEPs lead to PEP-508 which restricts project names
-        # to ASCII: https://peps.python.org/pep-0508/#names. Likewise, version numbers are also
-        # restricted to ASCII: https://peps.python.org/pep-0440/. Since the `.dist-info` dir
-        # path is defined as `<project name>-<version>.dist-info` in
-        # https://peps.python.org/pep-0427/, we are safe in assuming ASCII overall for the wheel
-        # metadata dir path.
-        metadata_dir = str(wheel_metadata_dir)
-
-        data_dir = re.sub(r"\.dist-info$", ".data", metadata_dir)
-
-        return cls(
-            location=wheel_path,
-            metadata_dir=metadata_dir,
-            metadata_files=metadata.files,
-            metadata=metadata,
-            data_dir=data_dir,
-        )
-
-    location = attr.ib()  # type: str
-    metadata_dir = attr.ib()  # type: str
-    metadata_files = attr.ib()  # type: MetadataFiles
-    metadata = attr.ib()  # type: WHEEL
-    data_dir = attr.ib()  # type: str
-
-    @property
-    def root_is_purelib(self):
-        # type: () -> bool
-        return self.metadata.root_is_purelib
-
-    def dist_metadata(self):
-        return DistMetadata.from_metadata_files(self.metadata_files)
-
-    def metadata_path(self, *components):
-        # typ: (*str) -> str
-        return os.path.join(self.metadata_dir, *components)
-
-    def data_path(self, *components):
-        # typ: (*str) -> str
-        return os.path.join(self.data_dir, *components)
-
-
 def install_wheel(
     wheel_path,  # type: str
     install_paths,  # type: InstallPaths

pex/resolver.py

@@ -23,7 +23,7 @@
 from pex.jobs import Raise, SpawnedJob, execute_parallel, iter_map_parallel
 from pex.network_configuration import NetworkConfiguration
 from pex.orderedset import OrderedSet
-from pex.pep_376 import InstalledWheel, LoadError
+from pex.pep_376 import InstalledWheel
 from pex.pep_425 import CompatibilityTags
 from pex.pep_427 import InstallableType, WheelError, install_wheel_chroot
 from pex.pep_503 import ProjectName
@@ -481,7 +481,7 @@ def finalize_install(self, install_requests):
         cached_fingerprint = None  # type: Optional[str]
         try:
             installed_wheel = InstalledWheel.load(self.install_chroot)
-        except LoadError:
+        except InstalledWheel.LoadError:
             # We support legacy chroots below by calculating the chroot fingerprint just in time.
             pass
         else:

pex/venv/installer.py

@@ -14,8 +14,7 @@
 from pex.dist_metadata import Distribution
 from pex.environment import PEXEnvironment
 from pex.orderedset import OrderedSet
-from pex.pep_376 import InstalledWheel, LoadError
-from pex.pep_427 import Wheel, WheelLoadError
+from pex.pep_376 import InstalledWheel
 from pex.pep_440 import Version
 from pex.pep_503 import ProjectName
 from pex.pex import PEX
@@ -26,6 +25,7 @@
 from pex.venv.bin_path import BinPath
 from pex.venv.install_scope import InstallScope
 from pex.venv.virtualenv import PipUnavailableError, Virtualenv
+from pex.wheel import Wheel, WheelMetadataLoadError
 
 if TYPE_CHECKING:
     import typing
@@ -258,7 +258,7 @@ def _populate_flat_deps(
             installed_wheel = InstalledWheel.load(dist.location)
             for src, dst in installed_wheel.reinstall_flat(target_dir=dest_dir, symlink=symlink):
                 yield src, dst
-        except LoadError:
+        except InstalledWheel.LoadError:
             for src, dst in _populate_legacy_dist(
                 dest_dir=dest_dir, bin_dir=dest_dir, dist=dist, symlink=symlink
             ):
@@ -471,10 +471,10 @@ def _populate_venv_deps(
                 venv, symlink=symlink, rel_extra_path=rel_extra_path
             ):
                 yield src, dst
-        except LoadError:
+        except InstalledWheel.LoadError:
             try:
                 wheel = Wheel.load(dist.location)
-            except WheelLoadError:
+            except WheelMetadataLoadError:
                 site_packages_dir = venv.site_packages_dir
             else:
                 site_packages_dir = venv.purelib if wheel.root_is_purelib else venv.platlib

pex/wheel.py

@@ -3,9 +3,17 @@
 
 from __future__ import absolute_import
 
+import os
+import re
 from email.message import Message
 
-from pex.dist_metadata import MetadataFiles, MetadataType, load_metadata, parse_message
+from pex.dist_metadata import (
+    DistMetadata,
+    MetadataFiles,
+    MetadataType,
+    load_metadata,
+    parse_message,
+)
 from pex.typing import TYPE_CHECKING, cast
 
 if TYPE_CHECKING:
@@ -16,16 +24,17 @@
     from pex.third_party import attr
 
 
+class WheelMetadataLoadError(Exception):
+    """Indicates an error loading WHEEL metadata."""
+
+
 @attr.s(frozen=True)
 class WHEEL(object):
     """The .whl WHEEL metadata file.
 
     See item 6 here for the WHEEL file contents: https://peps.python.org/pep-0427/#file-contents
     """
 
-    class LoadError(Exception):
-        """Indicates an error loading WHEEL metadata."""
-
     _CACHE = {}  # type: Dict[Text, WHEEL]
 
     @classmethod
@@ -35,13 +44,13 @@ def load(cls, location):
         if not wheel:
             metadata_files = load_metadata(location, restrict_types_to=(MetadataType.DIST_INFO,))
             if not metadata_files:
-                raise cls.LoadError(
+                raise WheelMetadataLoadError(
                     "Could not find any metadata in {wheel}.".format(wheel=location)
                 )
 
             metadata_bytes = metadata_files.read("WHEEL")
             if not metadata_bytes:
-                raise cls.LoadError(
+                raise WheelMetadataLoadError(
                     "Could not find WHEEL metadata in {wheel}.".format(wheel=location)
                 )
             metadata = parse_message(metadata_bytes)
@@ -59,3 +68,66 @@ def root_is_purelib(self):
         # See:
         #   https://peps.python.org/pep-0427/#installing-a-wheel-distribution-1-0-py32-none-any-whl
         return cast(bool, "true" == self.metadata.get("Root-Is-Purelib"))
+
+
+@attr.s(frozen=True)
+class Wheel(object):
+    @classmethod
+    def load(cls, wheel_path):
+        # type: (str) -> Wheel
+
+        metadata = WHEEL.load(wheel_path)
+
+        metadata_path = metadata.files.metadata_file_rel_path("WHEEL")
+        if not metadata_path:
+            raise WheelMetadataLoadError(
+                "Could not find WHEEL metadata in {wheel}.".format(wheel=wheel_path)
+            )
+
+        wheel_metadata_dir = os.path.dirname(metadata_path)
+        if not wheel_metadata_dir.endswith(".dist-info"):
+            raise WheelMetadataLoadError(
+                "Expected WHEEL metadata for {wheel} to be housed in a .dist-info directory, but was "
+                "found at {wheel_metadata_path}.".format(
+                    wheel=wheel_path, wheel_metadata_path=metadata_path
+                )
+            )
+        # Although not crisply defined, all PEPs lead to PEP-508 which restricts project names
+        # to ASCII: https://peps.python.org/pep-0508/#names. Likewise, version numbers are also
+        # restricted to ASCII: https://peps.python.org/pep-0440/. Since the `.dist-info` dir
+        # path is defined as `<project name>-<version>.dist-info` in
+        # https://peps.python.org/pep-0427/, we are safe in assuming ASCII overall for the wheel
+        # metadata dir path.
+        metadata_dir = str(wheel_metadata_dir)
+
+        data_dir = re.sub(r"\.dist-info$", ".data", metadata_dir)
+
+        return cls(
+            location=wheel_path,
+            metadata_dir=metadata_dir,
+            metadata_files=metadata.files,
+            metadata=metadata,
+            data_dir=data_dir,
+        )
+
+    location = attr.ib()  # type: str
+    metadata_dir = attr.ib()  # type: str
+    metadata_files = attr.ib()  # type: MetadataFiles
+    metadata = attr.ib()  # type: WHEEL
+    data_dir = attr.ib()  # type: str
+
+    @property
+    def root_is_purelib(self):
+        # type: () -> bool
+        return self.metadata.root_is_purelib
+
+    def dist_metadata(self):
+        return DistMetadata.from_metadata_files(self.metadata_files)
+
+    def metadata_path(self, *components):
+        # typ: (*str) -> str
+        return os.path.join(self.metadata_dir, *components)
+
+    def data_path(self, *components):
+        # typ: (*str) -> str
+        return os.path.join(self.data_dir, *components)

testing/docker.py

@@ -31,7 +31,7 @@
 
 @attr.s(frozen=True)
 class DockerVirtualenvRunner(object):
-    """Run's code in a venv created by Virtualenv at /virtualenv.venv in a docker container."""
+    """Runs code in a venv created by Virtualenv at /virtualenv.venv in a docker container."""
 
     @classmethod
     def create(