when installing from wheel files, parse the filename to build the requirement

pip/req.py

@@ -141,31 +141,46 @@ class InstallRequirement(object):
 
         if is_url(name):
             link = Link(name)
-        elif os.path.isdir(path) and (os.path.sep in name or name.startswith('.')):
+        elif (os.path.isdir(path)
+                and (os.path.sep in name or name.startswith('.'))):
             if not is_installable_dir(path):
-                raise InstallationError("Directory %r is not installable. File 'setup.py' not found." % name)
+                raise InstallationError(
+                    "Directory %r is not installable. File 'setup.py' not "
+                    "found." % name
+                )
             link = Link(path_to_url(name))
         elif is_archive_file(path):
             if not os.path.isfile(path):
-                logger.warn('Requirement %r looks like a filename, but the file does not exist', name)
+                logger.warn(
+                    'Requirement %r looks like a filename, but the file does '
+                    'not exist',
+                    name
+                )
             link = Link(path_to_url(name))
 
-        # If the line has an egg= definition, but isn't editable, pull the requirement out.
-        # Otherwise, assume the name is the req for the non URL/path/archive case.
-        if link and req is None:
-            url = link.url_without_fragment
-            req = link.egg_fragment  #when fragment is None, this will become an 'unnamed' requirement
+        # it's a local file, dir, or url
+        if link:
 
+            url = link.url_without_fragment
             # Handle relative file URLs
             if link.scheme == 'file' and re.search(r'\.\./', url):
                 url = path_to_url(os.path.normpath(os.path.abspath(link.path)))
 
-            # fail early for invalid or unsupported wheels
+            # wheel file
             if link.ext == wheel_ext:
-                wheel = Wheel(link.filename) # can raise InvalidWheelFilename
+                wheel = Wheel(link.filename)  # can raise InvalidWheelFilename
                 if not wheel.supported():
-                    raise UnsupportedWheel("%s is not a supported wheel on this platform." % wheel.filename)
+                    raise UnsupportedWheel(
+                        "%s is not a supported wheel on this platform." %
+                        wheel.filename
+                    )
+                req = "%s==%s" % (wheel.name, wheel.version)
+            else:
+                # set the req to the egg fragment.  when it's not there, this
+                # will become an 'unnamed' requirement
+                req = link.egg_fragment
 
+        # a requirement specifier
         else:
             req = name
 

tests/data/src/simplewheel-1.0/setup.py

@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+from setuptools import setup, find_packages
+
+setup(name='simplewheel',
+      version='1.0',
+      packages=find_packages()
+      )

tests/data/src/simplewheel-1.0/simple/__init__.py

@@ -0,0 +1 @@
+#

tests/data/src/simplewheel-2.0/setup.py

@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+from setuptools import setup, find_packages
+
+setup(name='simplewheel',
+      version='2.0',
+      packages=find_packages()
+      )

tests/data/src/simplewheel-2.0/simple/__init__.py

@@ -0,0 +1 @@
+#

tests/functional/test_install_wheel.py

@@ -272,3 +272,15 @@ def test_wheel_no_compiles_pyc(script, data):
     )
 
     assert not any(exists)
+
+
+def test_install_from_wheel_uninstalls_old_version(script, data):
+    # regression test for https://github.com/pypa/pip/issues/1825
+    package = data.packages.join("simplewheel-1.0-py2.py3-none-any.whl")
+    result = script.pip('install', package, '--no-index', expect_error=True)
+    package = data.packages.join("simplewheel-2.0-py2.py3-none-any.whl")
+    result = script.pip('install', package, '--no-index', expect_error=False)
+    dist_info_folder = script.site_packages / 'simplewheel-2.0.dist-info'
+    assert dist_info_folder in result.files_created
+    dist_info_folder = script.site_packages / 'simplewheel-1.0.dist-info'
+    assert dist_info_folder not in result.files_created

tests/unit/test_req.py

@@ -8,7 +8,10 @@ import pip.wheel
 
 from pkg_resources import Distribution
 from mock import Mock, patch, mock_open
-from pip.exceptions import PreviousBuildDirError, InvalidWheelFilename, UnsupportedWheel
+from pip.exceptions import (
+    PreviousBuildDirError, InvalidWheelFilename, UnsupportedWheel,
+)
+from pip._vendor import pkg_resources
 from pip.index import PackageFinder
 from pip.log import logger
 from pip.req import (read_text_file, InstallRequirement, RequirementSet,
@@ -85,6 +88,10 @@ class TestInstallRequirement(object):
         with pytest.raises(InvalidWheelFilename):
             req = InstallRequirement.from_line('invalid.whl')
 
+    def test_wheel_requirement_sets_req_attribute(self):
+        req = InstallRequirement.from_line('simple-0.1-py2.py3-none-any.whl')
+        assert req.req == pkg_resources.Requirement.parse('simple==0.1')
+
 
 def test_requirements_data_structure_keeps_order():
     requirements = Requirements()