Reverts #2493 - Upgrades will again contact the index

CHANGES.txt

@@ -27,9 +27,6 @@
 * Speed up installing a directory in certain cases by creating a sdist instead
   of copying the entire directory. (:pull:`2535`)
 
-* Speed up upgrading by skipping packages which use ``==`` and the specified
-  version is already installed. (:pull:`2493`)
-
 * Don't follow symlinks when uninstalling files (:pull:`2552`)
 
 * Upgrade the bundled copy of cachecontrol from 0.11.1 to 0.11.2.

pip/req/req_set.py

@@ -366,11 +366,7 @@ def _check_skip_installed(self, req_to_install, finder):
         req_to_install.check_if_exists()
         if req_to_install.satisfied_by:
             skip_reason = 'satisfied (use --upgrade to upgrade)'
-            # check that we don't already have an exact version match
-            # i.e. with at least one strict req operator
-            strict_req = set(('==', '===')) & set(
-                op for op, _ in req_to_install.req.specs)
-            if self.upgrade and (not strict_req or self.force_reinstall):
+            if self.upgrade:
                 best_installed = False
                 # For link based requirements we have to pull the
                 # tree down and inspect to assess the version #, so

tests/unit/test_req.py

@@ -8,7 +8,6 @@
 from mock import Mock, patch, mock_open
 from pip.exceptions import (
     PreviousBuildDirError, InvalidWheelFilename, UnsupportedWheel,
-    BestVersionAlreadyInstalled,
 )
 from pip.download import PipSession
 from pip.index import PackageFinder
@@ -55,60 +54,6 @@ def test_no_reuse_existing_build_dir(self, data):
             finder,
         )
 
-    @patch(
-        'pip.req.req_install.pkg_resources.get_distribution',
-        lambda x: pkg_resources.Distribution(
-            project_name='Pygments',
-            version='2.0.2',
-            location='/python',
-        )
-    )
-    def test_upgrade_no_look_at_pypi_if_exact_version_installed(
-            self, data):
-        """
-        If an exact version is specified for install, and that version is
-        already installed, then there is no point going to pypi as no install
-        is needed.
-        """
-        reqset = self.basic_reqset()
-        reqset.upgrade = True
-        req = InstallRequirement.from_line('pygments==2.0.2')
-        req.url = None
-        reqset.add_requirement(req)
-        finder = PackageFinder([data.find_links], [], session=PipSession())
-        with patch.object(finder, 'find_requirement') as find_requirement:
-            find_requirement.side_effect = AssertionError(
-                'find_requirement should NOT be called')
-            reqset.prepare_files(finder)
-
-    @patch(
-        'pip.req.req_install.pkg_resources.get_distribution',
-        lambda x: pkg_resources.Distribution(
-            project_name='Pygments',
-            version='2.0.2',
-            location='/python',
-        )
-    )
-    def test_upgrade_look_at_pypi_if_exact_version_installed_and_force(
-            self, data):
-        """
-        If an exact version is specified for install, and that version is
-        already installed, but --force-reinstall was provided, we should hit
-        PyPI.
-        """
-        reqset = self.basic_reqset()
-        reqset.upgrade = True
-        reqset.force_reinstall = True
-        req = InstallRequirement.from_line('pygments==2.0.2')
-        req.url = None
-        reqset.add_requirement(req)
-        finder = PackageFinder([data.find_links], [], session=PipSession())
-        with patch.object(finder, 'find_requirement') as find_requirement:
-            find_requirement.side_effect = BestVersionAlreadyInstalled
-            with pytest.raises(BestVersionAlreadyInstalled):
-                reqset.prepare_files(finder)
-                find_requirement.assert_called_once()
-
     def test_environment_marker_extras(self, data):
         """
         Test that the environment marker extras are used with