From e6bc8736983122adea222bf30f299dce551152ff Mon Sep 17 00:00:00 2001
From: Benoit Pierre <benoit.pierre@gmail.com>
Date: Mon, 12 Nov 2018 11:06:34 -0500
Subject: [PATCH 1/5] Prevent DistutilsOptionError when prefix is indicated in
 the global environment and --target is used. Fixes #4106.

---
 src/pip/_internal/locations.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/pip/_internal/locations.py b/src/pip/_internal/locations.py
index 183aaa39299..a4c79135014 100644
--- a/src/pip/_internal/locations.py
+++ b/src/pip/_internal/locations.py
@@ -157,7 +157,7 @@ def distutils_scheme(dist_name, user=False, home=None, root=None,
     # ideally, we'd prefer a scheme class that has no side-effects.
     assert not (user and prefix), "user={} prefix={}".format(user, prefix)
     i.user = user or i.user
-    if user:
+    if user or home:
         i.prefix = ""
     i.prefix = prefix or i.prefix
     i.home = home or i.home

From 65c38650f6788a35e5474871dfe9d055e644cd51 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Mon, 12 Nov 2018 11:09:56 -0500
Subject: [PATCH 2/5] Extend sanity check on user+prefix to include similar
 check for home+prefix. Ref #4106.

---
 src/pip/_internal/locations.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/pip/_internal/locations.py b/src/pip/_internal/locations.py
index a4c79135014..cd33969a024 100644
--- a/src/pip/_internal/locations.py
+++ b/src/pip/_internal/locations.py
@@ -156,6 +156,7 @@ 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={} prefix={}".format(user, prefix)
+    assert not (home and prefix), "home={} prefix={}".format(home, prefix)
     i.user = user or i.user
     if user or home:
         i.prefix = ""

From a66c696b995a6e9dbfc49f80a9c550dd668b4a03 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Mon, 12 Nov 2018 11:14:36 -0500
Subject: [PATCH 3/5] Add news entry. Ref #6008.

---
 news/6008.bugfix | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 news/6008.bugfix

diff --git a/news/6008.bugfix b/news/6008.bugfix
new file mode 100644
index 00000000000..ff83dfa0275
--- /dev/null
+++ b/news/6008.bugfix
@@ -0,0 +1 @@
+Prevent DistutilsOptionError when prefix is indicated in the global environment and `--target` is used.

From 3f013349642cdebccc80c916dd0f2c7826179779 Mon Sep 17 00:00:00 2001
From: Benoit Pierre <benoit.pierre@gmail.com>
Date: Mon, 12 Nov 2018 13:05:46 -0500
Subject: [PATCH 4/5] Add test capturing expectation. Ref #4106.

---
 tests/functional/test_install.py | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/tests/functional/test_install.py b/tests/functional/test_install.py
index 1be8e10e392..2cc76bb939e 100644
--- a/tests/functional/test_install.py
+++ b/tests/functional/test_install.py
@@ -1473,3 +1473,19 @@ def test_install_conflict_warning_can_be_suppressed(script, data):
         'install', '--no-index', pkgB_path, '--no-warn-conflicts'
     )
     assert "Successfully installed pkgB-2.0" in result2.stdout, str(result2)
+
+
+def test_target_install_ignores_distutils_config_install_prefix(script):
+    prefix = script.scratch_path / 'prefix'
+    Path(os.environ['HOME'], '.pydistutils.cfg').write(textwrap.dedent(
+        '''
+        [install]
+        prefix=%s
+        ''' % str(prefix)))
+    target = script.scratch_path / 'target'
+    result = script.pip_install_local('simplewheel', '-t', target)
+    assert (
+        "Successfully installed simplewheel" in result.stdout and
+        (target - script.base_path) in result.files_created and
+        (prefix - script.base_path) not in result.files_created
+    ), str(result)

From da9caa4a2c0d4168d79d1693967674c778253b24 Mon Sep 17 00:00:00 2001
From: Benoit Pierre <benoit.pierre@gmail.com>
Date: Mon, 12 Nov 2018 15:46:29 -0500
Subject: [PATCH 5/5] Fix test failures on Windows.

---
 tests/functional/test_install.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tests/functional/test_install.py b/tests/functional/test_install.py
index 2cc76bb939e..9ba75bdd40b 100644
--- a/tests/functional/test_install.py
+++ b/tests/functional/test_install.py
@@ -1477,7 +1477,10 @@ def test_install_conflict_warning_can_be_suppressed(script, data):
 
 def test_target_install_ignores_distutils_config_install_prefix(script):
     prefix = script.scratch_path / 'prefix'
-    Path(os.environ['HOME'], '.pydistutils.cfg').write(textwrap.dedent(
+    distutils_config = Path(os.path.expanduser('~'),
+                            'pydistutils.cfg' if sys.platform == 'win32'
+                            else '.pydistutils.cfg')
+    distutils_config.write(textwrap.dedent(
         '''
         [install]
         prefix=%s