Fix pip install --target

pip/commands/install.py

@@ -256,6 +256,16 @@ def run(self, options, args):
 
         temp_target_dir = None
         if options.target_dir:
+            if options.prefix_path:
+                raise CommandError(
+                    "Can not combine '--target' and '--prefix' as they imply "
+                    "different installation locations"
+                )
+            if options.use_user_site:
+                raise CommandError(
+                    "Can not combine '--target' and '--user' as they imply "
+                    "different installation locations"
+                )
             options.ignore_installed = True
             temp_target_dir = tempfile.mkdtemp()
             options.target_dir = os.path.abspath(options.target_dir)
@@ -266,6 +276,7 @@ def run(self, options, args):
                     "continue."
                 )
             install_options.append('--home=' + temp_target_dir)
+            install_options.append('--prefix=')
 
         global_options = options.global_options or []
 

pip/download.py

@@ -388,7 +388,12 @@ def request(self, method, url, *args, **kwargs):
 
 def get_file_content(url, comes_from=None, session=None):
     """Gets the content of a file; it may be a filename, file: URL, or
-    http: URL.  Returns (location, content).  Content is unicode."""
+    http: URL.  Returns (location, content).  Content is unicode.
+
+    :param url:         File path or url.
+    :param comes_from:  Origin description of requirements.
+    :param session:     Instance of pip.download.PipSession.
+    """
     if session is None:
         raise TypeError(
             "get_file_content() missing 1 required keyword argument: 'session'"

pip/locations.py

@@ -144,9 +144,11 @@ def distutils_scheme(dist_name, user=False, home=None, root=None,
     # or user base for installations during finalize_options()
     # ideally, we'd prefer a scheme class that has no side-effects.
     assert not (user and prefix), "user={0} prefix={1}".format(user, prefix)
-    i.user = user or i.user
-    if user:
+    assert not (home and prefix), "home={0} prefix={1}".format(home, prefix)
+    assert not (home and user), "home={0} user={1}".format(home, user)
+    if user or home:
         i.prefix = ""
+    i.user = user or i.user
     i.prefix = prefix or i.prefix
     i.home = home or i.home
     i.root = root or i.root

tests/functional/test_install.py

@@ -690,6 +690,37 @@ def test_install_package_conflict_prefix_and_user(script, data):
     )
 
 
+def test_install_package_conflict_prefix_and_target(script, data):
+    """
+    Test installing a package using pip install --prefix --user errors out
+    """
+    prefix_path = script.scratch_path / 'prefix'
+    target_path = script.scratch_path / 'target'
+    result = script.pip(
+        'install', '-f', data.find_links, '--no-index', '--target', target_path,
+        '--prefix', prefix_path, 'simple==1.0',
+        expect_error=True, quiet=True,
+    )
+    assert (
+        "Can not combine '--target' and '--prefix'" in result.stderr
+    )
+
+
+def test_install_package_conflict_target_and_user(script, data):
+    """
+    Test installing a package using pip install --prefix --user errors out
+    """
+    target_path = script.scratch_path / 'target'
+    result = script.pip(
+        'install', '-f', data.find_links, '--no-index', '--user',
+        '--target', target_path, 'simple==1.0',
+        expect_error=True, quiet=True,
+    )
+    assert (
+        "Can not combine '--target' and '--user'" in result.stderr
+    )
+
+
 # skip on win/py3 for now, see issue #782
 @pytest.mark.skipif("sys.platform == 'win32' and sys.version_info >= (3,)")
 def test_install_package_that_emits_unicode(script, data):

tests/functional/test_install_reqs.py

@@ -241,6 +241,45 @@ def test_nowheel_user_with_prefix_in_pydistutils_cfg(script, data, virtualenv):
             ) in result.stderr
 
 
+@pytest.mark.network
+def test_wheel_target_with_prefix_in_pydistutils_cfg(script, data, virtualenv):
+    # Make sure wheel is available in the virtualenv
+    script.pip('install', 'wheel')
+    virtualenv.system_site_packages = True
+    homedir = script.environ["HOME"]
+    script.scratch_path.join("bin").mkdir()
+    with open(os.path.join(homedir, ".pydistutils.cfg"), "w") as cfg:
+        cfg.write(textwrap.dedent("""
+            [install]
+            prefix=%s""" % script.scratch_path))
+
+    target_path = script.scratch_path / 'target'
+    result = script.pip('install', '--target', target_path, '--no-index', '-f',
+                        data.find_links, 'requiresupper')
+    # Check that we are really installing a wheel
+    assert 'Running setup.py install for requiresupper' not in result.stdout
+    assert 'installed requiresupper' in result.stdout
+
+
+def test_nowheel_target_with_prefix_in_pydistutils_cfg(script, data, virtualenv):
+    virtualenv.system_site_packages = True
+    homedir = script.environ["HOME"]
+    script.scratch_path.join("bin").mkdir()
+    with open(os.path.join(homedir, ".pydistutils.cfg"), "w") as cfg:
+        cfg.write(textwrap.dedent("""
+            [install]
+            prefix=%s""" % script.scratch_path))
+
+    target_path = script.scratch_path / 'target'
+    result = script.pip('install', '--no-use-wheel', '--target', target_path,
+                        '--no-index', '-f', data.find_links, 'requiresupper',
+                        expect_stderr=True)
+    assert 'installed requiresupper' in result.stdout
+    assert ('DEPRECATION: --no-use-wheel is deprecated and will be removed '
+            'in the future.  Please use --no-binary :all: instead.\n'
+            ) in result.stderr
+
+
 def test_install_option_in_requirements_file(script, data, virtualenv):
     """
     Test --install-option in requirements file overrides same option in cli