Mutually exclusive --target, --user and --prefix

news/4111.bugfix

@@ -0,0 +1 @@
+pip install ``--target``, ``--user``, and ``--prefix`` are now mutually exclusive.

src/pip/_internal/commands/install.py

@@ -198,6 +198,11 @@ def run(self, options, args):
                     "Can not combine '--user' and '--prefix' as they imply "
                     "different installation locations"
                 )
+            if options.target_dir:
+                raise CommandError(
+                    "Can not combine '--user' and '--target' as they imply "
+                    "different installation locations"
+                )
             if virtualenv_no_global():
                 raise InstallationError(
                     "Can not perform a '--user' install. User site-packages "
@@ -208,6 +213,11 @@ def run(self, options, args):
 
         target_temp_dir = TempDirectory(kind="target")
         if options.target_dir:
+            if options.prefix_path:
+                raise CommandError(
+                    "Can not combine '--target' and '--prefix' as they imply "
+                    "different installation locations"
+                )
             options.ignore_installed = True
             options.target_dir = os.path.abspath(options.target_dir)
             if (os.path.exists(options.target_dir) and not
@@ -220,6 +230,7 @@ def run(self, options, args):
             # Create a target directory for using with the target option
             target_temp_dir.create()
             install_options.append('--home=' + target_temp_dir.path)
+            install_options.append('--prefix=')
 
         global_options = options.global_options or []
 

src/pip/_internal/locations.py

@@ -156,9 +156,11 @@ 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

@@ -712,6 +712,37 @@ def test_install_package_conflict_prefix_and_user(script, data):
     )
 
 
+def test_install_package_conflict_target_and_user(script, data):
+    """
+    Test installing a package using pip install --target --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 '--user' and '--target'" in result.stderr
+    )
+
+
+def test_install_package_conflict_prefix_and_target(script, data):
+    """
+    Test installing a package using pip install --prefix --targetx 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
+    )
+
+
 # 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

@@ -10,6 +10,12 @@
 from tests.lib.local_repos import local_checkout
 
 
+if os.name == 'posix':
+    distutils_cfg = os.path.expanduser('~/.pydistutils.cfg')
+else:
+    distutils_cfg = os.path.expanduser('~\\.pydistutils.cfg')
+
+
 @pytest.mark.network
 def test_requirements_file(script):
     """
@@ -229,13 +235,8 @@ def test_wheel_user_with_prefix_in_pydistutils_cfg(
     # Make sure wheel is available in the virtualenv
     script.pip('install', 'wheel', '--no-index', '-f', common_wheels)
     virtualenv.system_site_packages = True
-    if os.name == 'posix':
-        user_filename = ".pydistutils.cfg"
-    else:
-        user_filename = "pydistutils.cfg"
-    user_cfg = os.path.join(os.path.expanduser('~'), user_filename)
     script.scratch_path.join("bin").mkdir()
-    with open(user_cfg, "w") as cfg:
+    with open(distutils_cfg, "w") as cfg:
         cfg.write(textwrap.dedent("""
             [install]
             prefix=%s""" % script.scratch_path))
@@ -249,6 +250,53 @@ def test_wheel_user_with_prefix_in_pydistutils_cfg(
     assert 'installed requiresupper' in result.stdout
 
 
+def test_nowheel_user_with_prefix_in_pydistutils_cfg(script, data, virtualenv):
+    virtualenv.system_site_packages = True
+    with open(distutils_cfg, "w") as cfg:
+        cfg.write(textwrap.dedent("""
+            [install]
+            prefix=%s""" % script.scratch_path))
+
+    result = script.pip('install', '--no-binary=:all:', '--user', '--no-index',
+                        '-f', data.find_links, 'requiresupper',
+                        expect_stderr=True)
+    assert 'installed requiresupper' in result.stdout
+
+
+@pytest.mark.network
+def test_wheel_target_with_prefix_in_pydistutils_cfg(
+        script, data, virtualenv, common_wheels):
+    # pip needs `wheel` to build `requiresupper` wheel before installing
+    script.pip('install', 'wheel', '--no-index', '-f', common_wheels)
+    with open(distutils_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, '-f', common_wheels,
+                        '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):
+    with open(distutils_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-binary=:all:',
+                        '--target', target_path,
+                        '--no-index', '-f', data.find_links, 'requiresupper',
+                        expect_stderr=True)
+    assert 'installed requiresupper' in result.stdout
+
+
 def test_install_option_in_requirements_file(script, data, virtualenv):
     """
     Test --install-option in requirements file overrides same option in cli