Fix editable-or-not egg-info uninstallation

src/pip/_internal/metadata/base.py

@@ -214,6 +214,14 @@ def canonical_name(self) -> NormalizedName:
  def version(self) -> DistributionVersion:
  raise NotImplementedError()
 
+ @property
+ def setuptools_filename(self) -> str:
+ """Convert a project name to its setuptools-compatible filename.
+
+ This is a copy of ``pkg_resources.to_filename()`` for compatibility.
+ """
+ return self.raw_name.replace("-", "_")
+
  @property
  def direct_url(self) -> Optional[DirectUrl]:
  """Obtain a DirectUrl from this distribution.

src/pip/_internal/req/req_uninstall.py

@@ -455,11 +455,21 @@ def from_dist(cls, dist: BaseDistribution) -> "UninstallPathSet":
  paths_to_remove = cls(dist)
  develop_egg_link = egg_link_path_from_location(dist.raw_name)
 
+ # Distribution is installed with metadata in a "flat" .egg-info
+ # directory. This means it is not a modern .dist-info installation, an
+ # egg, or legacy editable.
+ setuptools_flat_installation = (
+ dist.installed_with_setuptools_egg_info
+ and info_location is not None
+ and os.path.exists(info_location)
+ # If dist is editable and the location points to a ``.egg-info``,
+ # we are in fact in the legacy editable case.
+ and not info_location.endswith(f"{dist.setuptools_filename}.egg-info")
+ )
+
  # Uninstall cases order do matter as in the case of 2 installs of the
  # same package, pip needs to uninstall the currently detected version
- if dist.installed_with_setuptools_egg_info and not dist.editable:
- # if dist is editable and the location points to a ``.egg-info``,
- # we are in fact in the ``.egg_link`` case.
+ if setuptools_flat_installation:
  if info_location is not None:
  paths_to_remove.add(info_location)
  installed_files = dist.iter_declared_entries()
@@ -512,15 +522,14 @@ def from_dist(cls, dist: BaseDistribution) -> "UninstallPathSet":
  for path in uninstallation_paths(dist):
  paths_to_remove.add(path)
 
- elif dist.editable and develop_egg_link:
+ elif develop_egg_link:
  # PEP 660 modern editable is handled in the ``.dist-info`` case
  # above, so this only covers the setuptools-style editable.
  with open(develop_egg_link) as fh:
  link_pointer = os.path.normcase(fh.readline().strip())
- assert (
- link_pointer == dist_location
- ), "Egg-link {} does not match installed location of {} (at {})".format(
- link_pointer, dist.raw_name, dist_location
+ assert link_pointer == dist_location, (
+ f"Egg-link {link_pointer} does not match installed location of "
+ f"{dist.raw_name} (at {dist_location})"
  )
  paths_to_remove.add(develop_egg_link)
  easy_install_pth = os.path.join(