Cleanup arguments, add docstring

src/pip/_internal/req/req_install.py

@@ -484,9 +484,9 @@ class InstallRequirement(object):
         # type: (...) -> None
         wheel.install_unpacked_wheel(
             self.name,
-            str(self.req),
             wheeldir,
             scheme=scheme,
+            req_description=str(self.req),
             pycompile=pycompile,
             warn_script_location=warn_script_location,
         )

src/pip/_internal/wheel.py

@@ -57,7 +57,6 @@ if MYPY_CHECK_RUNNING:
         Dict, List, Optional, Sequence, Mapping, Tuple, IO, Text, Any,
         Iterable, Callable, Set,
     )
-    from pip._vendor.packaging.requirements import Requirement
     from pip._internal.req.req_install import InstallRequirement
     from pip._internal.operations.prepare import (
         RequirementPreparer
@@ -332,14 +331,24 @@ class PipScriptMaker(ScriptMaker):
 
 def install_unpacked_wheel(
     name,  # type: str
-    req,  # type: str
     wheeldir,  # type: str
     scheme,  # type: Mapping[str, str]
+    req_description,  # type: str
     pycompile=True,  # type: bool
     warn_script_location=True  # type: bool
 ):
     # type: (...) -> None
-    """Install a wheel"""
+    """Install a wheel.
+
+    :param name: Name of the project to install
+    :param wheeldir: Base directory of the unpacked wheel
+    :param scheme: Distutils scheme dictating the install directories
+    :param req_description: String used in place of the requirement, for
+        logging
+    :param pycompile: Whether to byte-compile installed Python files
+    :param warn_script_location: Whether to check that scripts are installed
+        into a directory on PATH
+    """
     # TODO: Investigate and break this up.
     # TODO: Look into moving this into a dedicated class for representing an
     #       installation.
@@ -390,13 +399,16 @@ def install_unpacked_wheel(
                 if is_base and basedir == '' and destsubdir.endswith('.data'):
                     data_dirs.append(s)
                     continue
-                elif (is_base and
-                        s.endswith('.dist-info') and
-                        canonicalize_name(s).startswith(
-                            canonicalize_name(name))):
-                    assert not info_dir, ('Multiple .dist-info directories: ' +
-                                          destsubdir + ', ' +
-                                          ', '.join(info_dir))
+                elif (
+                    is_base and
+                    s.endswith('.dist-info') and
+                    canonicalize_name(s).startswith(canonicalize_name(name))
+                ):
+                    assert not info_dir, (
+                        'Multiple .dist-info directories: {}, '.format(
+                            destsubdir
+                        ) + ', '.join(info_dir)
+                    )
                     info_dir.append(destsubdir)
             for f in files:
                 # Skip unwanted files
@@ -449,7 +461,9 @@ def install_unpacked_wheel(
 
     clobber(source, lib_dir, True)
 
-    assert info_dir, "%s .dist-info directory not found" % req
+    assert info_dir, "{} .dist-info directory not found".format(
+        req_description
+    )
 
     # Get the defined entry points
     ep_file = os.path.join(info_dir[0], 'entry_points.txt')
@@ -592,7 +606,7 @@ def install_unpacked_wheel(
             "Invalid script entry point: {} for req: {} - A callable "
             "suffix is required. Cf https://packaging.python.org/en/"
             "latest/distributing.html#console-scripts for more "
-            "information.".format(entry, req)
+            "information.".format(entry, req_description)
         )
 
     if warn_script_location:

tests/unit/test_wheel.py

@@ -661,7 +661,11 @@ class TestInstallUnpackedWheel(object):
     def test_std_install(self, data, tmpdir):
         self.prep(data, tmpdir)
         wheel.install_unpacked_wheel(
-            self.name, str(self.req), self.src, scheme=self.scheme)
+            self.name,
+            self.src,
+            scheme=self.scheme,
+            req_description=str(self.req),
+        )
         self.assert_installed()
 
     def test_install_prefix(self, data, tmpdir):
@@ -677,9 +681,9 @@ class TestInstallUnpackedWheel(object):
         )
         wheel.install_unpacked_wheel(
             self.name,
-            str(self.req),
             self.src,
             scheme=scheme,
+            req_description=str(self.req),
         )
 
         bin_dir = 'Scripts' if WINDOWS else 'bin'
@@ -697,7 +701,11 @@ class TestInstallUnpackedWheel(object):
         os.makedirs(src_empty_dir)
         assert os.path.isdir(src_empty_dir)
         wheel.install_unpacked_wheel(
-            self.name, str(self.req), self.src, scheme=self.scheme)
+            self.name,
+            self.src,
+            scheme=self.scheme,
+            req_description=str(self.req),
+        )
         self.assert_installed()
         assert not os.path.isdir(
             os.path.join(self.dest_dist_info, 'empty_dir'))