Move dist-related logic from misc into metadata

src/pip/_internal/metadata/base.py

@@ -49,10 +49,12 @@ def from_paths(cls, paths):
 
     def get_distribution(self, name):
         # type: (str) -> Optional[BaseDistribution]
+        """Given a requirement name, return the installed distributions."""
         raise NotImplementedError()
 
     def iter_distributions(self):
         # type: () -> Iterator[BaseDistribution]
+        """Iterate through installed distributions."""
         raise NotImplementedError()
 
     def iter_installed_distributions(
@@ -64,6 +66,17 @@ def iter_installed_distributions(
         user_only=False,  # type: bool
     ):
         # type: (...) -> Iterator[BaseDistribution]
+        """Return a list of installed distributions.
+
+        :param local_only: If True (default), only return installations
+        local to the current virtualenv, if in a virtualenv.
+        :param skip: An iterable of canonicalized project names to ignore;
+            defaults to ``stdlib_pkgs``.
+        :param include_editables: If False, don't report editables.
+        :param editables_only: If True, only report editables.
+        :param user_only: If True, only report installations in the user
+        site directory.
+        """
         it = self.iter_distributions()
         if local_only:
             it = (d for d in it if d.local)

src/pip/_internal/metadata/pkg_resources.py

@@ -61,14 +61,42 @@ def from_paths(cls, paths):
         # type: (List[str]) -> BaseEnvironment
         return cls(pkg_resources.WorkingSet(paths))
 
+    def _search_distribution(self, name):
+        """Find a distribution matching the ``name`` in the environment.
+
+        This searches from *all* distributions available in the environment, to
+        match the behavior of ``pkg_resources.get_distribution()``.
+        """
+        # type: (str) -> Optional[BaseDistribution]
+        canonical_name = canonicalize_name(name)
+        for dist in self.iter_distributions():
+            if dist.canonical_name == canonical_name:
+                return dist
+        return None
+
     def get_distribution(self, name):
         # type: (str) -> Optional[BaseDistribution]
-        req = pkg_resources.Requirement(name)
+
+        # Search the distribution by looking through the working set.
+        dist = self._search_distribution(name)
+        if dist:
+            return dist
+
+        # If distribution could not be found, call working_set.require to
+        # update the working set, and try to find the distribution again.
+        # This might happen for e.g. when you install a package twice, once
+        # using setup.py develop and again using setup.py install. Now when
+        # running pip uninstall twice, the package gets removed from the
+        # working set in the first uninstall, so we have to populate the
+        # working set again so that pip knows about it and the packages gets
+        # picked up and is successfully uninstalled the second time too.
         try:
-            dist = self._ws.find(req)
+            # We didn't pass in any version specifiers, so this can never
+            # raise pkg_resources.VersionConflict.
+            self._ws.require(name)
         except pkg_resources.DistributionNotFound:
             return None
-        return Distribution(dist)
+        return self._search_distribution(name)
 
     def iter_distributions(self):
         # type: () -> Iterator[BaseDistribution]

src/pip/_internal/utils/misc.py

@@ -18,7 +18,6 @@
 from itertools import filterfalse, tee, zip_longest
 
 from pip._vendor import pkg_resources
-from pip._vendor.packaging.utils import canonicalize_name
 
 # NOTE: retrying is not annotated in typeshed as on 2017-07-17, which is
 #       why we ignore the type on this import.
@@ -402,86 +401,20 @@ def get_installed_distributions(
         paths=None  # type: Optional[List[str]]
 ):
     # type: (...) -> List[Distribution]
-    """
-    Return a list of installed Distribution objects.
-
-    If ``local_only`` is True (default), only return installations
-    local to the current virtualenv, if in a virtualenv.
-
-    ``skip`` argument is an iterable of lower-case project names to
-    ignore; defaults to stdlib_pkgs
-
-    If ``include_editables`` is False, don't report editables.
-
-    If ``editables_only`` is True , only report editables.
-
-    If ``user_only`` is True , only report installations in the user
-    site directory.
-
-    If ``paths`` is set, only report the distributions present at the
-    specified list of locations.
-    """
-    if paths:
-        working_set = pkg_resources.WorkingSet(paths)
-    else:
-        working_set = pkg_resources.working_set
-
-    if local_only:
-        local_test = dist_is_local
-    else:
-        def local_test(d):
-            return True
-
-    if include_editables:
-        def editable_test(d):
-            return True
-    else:
-        def editable_test(d):
-            return not dist_is_editable(d)
-
-    if editables_only:
-        def editables_only_test(d):
-            return dist_is_editable(d)
-    else:
-        def editables_only_test(d):
-            return True
-
-    if user_only:
-        user_test = dist_in_usersite
-    else:
-        def user_test(d):
-            return True
-
-    return [d for d in working_set
-            if local_test(d) and
-            d.key not in skip and
-            editable_test(d) and
-            editables_only_test(d) and
-            user_test(d)
-            ]
-
-
-def _search_distribution(req_name):
-    # type: (str) -> Optional[Distribution]
-    """Find a distribution matching the ``req_name`` in the environment.
-
-    This searches from *all* distributions available in the environment, to
-    match the behavior of ``pkg_resources.get_distribution()``.
-    """
-    # Canonicalize the name before searching in the list of
-    # installed distributions and also while creating the package
-    # dictionary to get the Distribution object
-    req_name = canonicalize_name(req_name)
-    packages = get_installed_distributions(
-        local_only=False,
-        skip=(),
-        include_editables=True,
-        editables_only=False,
-        user_only=False,
-        paths=None,
+    """Return a list of installed Distribution objects.
+
+    Left for compatibility until direct pkg_resources uses are refactored out.
+    """
+    from pip._internal.metadata import get_environment
+    from pip._internal.metadata.pkg_resources import Distribution as _Dist
+    dists = get_environment(paths).iter_installed_distributions(
+        local_only=local_only,
+        skip=skip,
+        include_editables=include_editables,
+        editables_only=editables_only,
+        user_only=user_only,
     )
-    pkg_dict = {canonicalize_name(p.key): p for p in packages}
-    return pkg_dict.get(req_name)
+    return [cast(_Dist, dist)._dist for dist in dists]
 
 
 def get_distribution(req_name):
@@ -490,26 +423,15 @@ def get_distribution(req_name):
 
     This searches from *all* distributions available in the environment, to
     match the behavior of ``pkg_resources.get_distribution()``.
-    """
 
-    # Search the distribution by looking through the working set
-    dist = _search_distribution(req_name)
-
-    # If distribution could not be found, call working_set.require
-    # to update the working set, and try to find the distribution
-    # again.
-    # This might happen for e.g. when you install a package
-    # twice, once using setup.py develop and again using setup.py install.
-    # Now when run pip uninstall twice, the package gets removed
-    # from the working set in the first uninstall, so we have to populate
-    # the working set again so that pip knows about it and the packages
-    # gets picked up and is successfully uninstalled the second time too.
-    if not dist:
-        try:
-            pkg_resources.working_set.require(req_name)
-        except pkg_resources.DistributionNotFound:
-            return None
-    return _search_distribution(req_name)
+    Left for compatibility until direct pkg_resources uses are refactored out.
+    """
+    from pip._internal.metadata import get_environment
+    from pip._internal.metadata.pkg_resources import Distribution as _Dist
+    dist = get_environment().get_distribution(req_name)
+    if dist is None:
+        return None
+    return cast(_Dist, dist)._dist
 
 
 def egg_link_path(dist):