We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Protect a few more requests imports
In Debian, we unbundle requests, and further, we unbundled all vendored packages from requests.  This causes pip's vendoring algorithm to fail.  I had to add this patch to the Debian packaging.

```
From 144ba146cde273b815a80859537b09c068fd47e6 Mon Sep 17 00:00:00 2001
From: Barry Warsaw <barry@python.org>
Date: Fri, 29 Jan 2016 16:56:43 -0500
Subject: Debian already unbundles things from requests.

Patch-Name: handle-unbundled-requests.patch

---
 pip/_vendor/__init__.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/pip/_vendor/__init__.py b/pip/_vendor/__init__.py
index 1cb35a1..c64896a 100644
--- a/pip/_vendor/__init__.py
+++ b/pip/_vendor/__init__.py
@@ -82,8 +82,12 @@ if DEBUNDLED:
     vendored("requests.packages.urllib3.fields")
     vendored("requests.packages.urllib3.filepost")
     vendored("requests.packages.urllib3.packages")
-    vendored("requests.packages.urllib3.packages.ordered_dict")
-    vendored("requests.packages.urllib3.packages.six")
+    try:
+        vendored("requests.packages.urllib3.packages.ordered_dict")
+        vendored("requests.packages.urllib3.packages.six")
+    except ImportError:
+        # Debian already unbundles these from requests.
+        pass
     vendored("requests.packages.urllib3.packages.ssl_match_hostname")
     vendored("requests.packages.urllib3.packages.ssl_match_hostname."
              "_implementation")
```


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `pip/_vendor/__init__.py`
Content:
```
1 """
2 pip._vendor is for vendoring dependencies of pip to prevent needing pip to
3 depend on something external.
4 
5 Files inside of pip._vendor should be considered immutable and should only be
6 updated to versions from upstream.
7 """
8 from __future__ import absolute_import
9 
10 import glob
11 import os.path
12 import sys
13 
14 # Downstream redistributors which have debundled our dependencies should also
15 # patch this value to be true. This will trigger the additional patching
16 # to cause things like "six" to be available as pip.
17 DEBUNDLED = False
18 
19 # By default, look in this directory for a bunch of .whl files which we will
20 # add to the beginning of sys.path before attempting to import anything. This
21 # is done to support downstream re-distributors like Debian and Fedora who
22 # wish to create their own Wheels for our dependencies to aid in debundling.
23 WHEEL_DIR = os.path.abspath(os.path.dirname(__file__))
24 
25 
26 # Define a small helper function to alias our vendored modules to the real ones
27 # if the vendored ones do not exist. This idea of this was taken from
28 # https://github.com/kennethreitz/requests/pull/2567.
29 def vendored(modulename):
30     vendored_name = "{0}.{1}".format(__name__, modulename)
31 
32     try:
33         __import__(vendored_name, globals(), locals(), level=0)
34     except ImportError:
35         __import__(modulename, globals(), locals(), level=0)
36         sys.modules[vendored_name] = sys.modules[modulename]
37         base, head = vendored_name.rsplit(".", 1)
38         setattr(sys.modules[base], head, sys.modules[modulename])
39 
40 
41 # If we're operating in a debundled setup, then we want to go ahead and trigger
42 # the aliasing of our vendored libraries as well as looking for wheels to add
43 # to our sys.path. This will cause all of this code to be a no-op typically
44 # however downstream redistributors can enable it in a consistent way across
45 # all platforms.
46 if DEBUNDLED:
47     # Actually look inside of WHEEL_DIR to find .whl files and add them to the
48     # front of our sys.path.
49     sys.path[:] = glob.glob(os.path.join(WHEEL_DIR, "*.whl")) + sys.path
50 
51     # Actually alias all of our vendored dependencies.
52     vendored("cachecontrol")
53     vendored("colorama")
54     vendored("distlib")
55     vendored("html5lib")
56     vendored("lockfile")
57     vendored("six")
58     vendored("six.moves")
59     vendored("six.moves.urllib")
60     vendored("packaging")
61     vendored("packaging.version")
62     vendored("packaging.specifiers")
63     vendored("pkg_resources")
64     vendored("progress")
65     vendored("retrying")
66     vendored("requests")
67     vendored("requests.packages")
68     vendored("requests.packages.urllib3")
69     vendored("requests.packages.urllib3._collections")
70     vendored("requests.packages.urllib3.connection")
71     vendored("requests.packages.urllib3.connectionpool")
72     vendored("requests.packages.urllib3.contrib")
73     try:
74         vendored("requests.packages.urllib3.contrib.ntlmpool")
75     except ImportError:
76         pass
77     try:
78         vendored("requests.packages.urllib3.contrib.pyopenssl")
79     except ImportError:
80         pass
81     vendored("requests.packages.urllib3.exceptions")
82     vendored("requests.packages.urllib3.fields")
83     vendored("requests.packages.urllib3.filepost")
84     vendored("requests.packages.urllib3.packages")
85     vendored("requests.packages.urllib3.packages.ordered_dict")
86     vendored("requests.packages.urllib3.packages.six")
87     vendored("requests.packages.urllib3.packages.ssl_match_hostname")
88     vendored("requests.packages.urllib3.packages.ssl_match_hostname."
89              "_implementation")
90     vendored("requests.packages.urllib3.poolmanager")
91     vendored("requests.packages.urllib3.request")
92     vendored("requests.packages.urllib3.response")
93     vendored("requests.packages.urllib3.util")
94     vendored("requests.packages.urllib3.util.connection")
95     vendored("requests.packages.urllib3.util.request")
96     vendored("requests.packages.urllib3.util.response")
97     vendored("requests.packages.urllib3.util.retry")
98     vendored("requests.packages.urllib3.util.ssl_")
99     vendored("requests.packages.urllib3.util.timeout")
100     vendored("requests.packages.urllib3.util.url")
101
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/pip/_vendor/__init__.py b/pip/_vendor/__init__.py
--- a/pip/_vendor/__init__.py
+++ b/pip/_vendor/__init__.py
@@ -32,10 +32,22 @@
     try:
         __import__(vendored_name, globals(), locals(), level=0)
     except ImportError:
-        __import__(modulename, globals(), locals(), level=0)
-        sys.modules[vendored_name] = sys.modules[modulename]
-        base, head = vendored_name.rsplit(".", 1)
-        setattr(sys.modules[base], head, sys.modules[modulename])
+        try:
+            __import__(modulename, globals(), locals(), level=0)
+        except ImportError:
+            # We can just silently allow import failures to pass here. If we
+            # got to this point it means that ``import pip._vendor.whatever``
+            # failed and so did ``import whatever``. Since we're importing this
+            # upfront in an attempt to alias imports, not erroring here will
+            # just mean we get a regular import error whenever pip *actually*
+            # tries to import one of these modules to use it, which actually
+            # gives us a better error message than we would have otherwise
+            # gotten.
+            pass
+        else:
+            sys.modules[vendored_name] = sys.modules[modulename]
+            base, head = vendored_name.rsplit(".", 1)
+            setattr(sys.modules[base], head, sys.modules[modulename])
 
 
 # If we're operating in a debundled setup, then we want to go ahead and trigger
@@ -70,14 +82,8 @@
     vendored("requests.packages.urllib3.connection")
     vendored("requests.packages.urllib3.connectionpool")
     vendored("requests.packages.urllib3.contrib")
-    try:
-        vendored("requests.packages.urllib3.contrib.ntlmpool")
-    except ImportError:
-        pass
-    try:
-        vendored("requests.packages.urllib3.contrib.pyopenssl")
-    except ImportError:
-        pass
+    vendored("requests.packages.urllib3.contrib.ntlmpool")
+    vendored("requests.packages.urllib3.contrib.pyopenssl")
     vendored("requests.packages.urllib3.exceptions")
     vendored("requests.packages.urllib3.fields")
     vendored("requests.packages.urllib3.filepost")

{"golden_diff": "diff --git a/pip/_vendor/__init__.py b/pip/_vendor/__init__.py\n--- a/pip/_vendor/__init__.py\n+++ b/pip/_vendor/__init__.py\n@@ -32,10 +32,22 @@\n     try:\n         __import__(vendored_name, globals(), locals(), level=0)\n     except ImportError:\n-        __import__(modulename, globals(), locals(), level=0)\n-        sys.modules[vendored_name] = sys.modules[modulename]\n-        base, head = vendored_name.rsplit(\".\", 1)\n-        setattr(sys.modules[base], head, sys.modules[modulename])\n+        try:\n+            __import__(modulename, globals(), locals(), level=0)\n+        except ImportError:\n+            # We can just silently allow import failures to pass here. If we\n+            # got to this point it means that ``import pip._vendor.whatever``\n+            # failed and so did ``import whatever``. Since we're importing this\n+            # upfront in an attempt to alias imports, not erroring here will\n+            # just mean we get a regular import error whenever pip *actually*\n+            # tries to import one of these modules to use it, which actually\n+            # gives us a better error message than we would have otherwise\n+            # gotten.\n+            pass\n+        else:\n+            sys.modules[vendored_name] = sys.modules[modulename]\n+            base, head = vendored_name.rsplit(\".\", 1)\n+            setattr(sys.modules[base], head, sys.modules[modulename])\n \n \n # If we're operating in a debundled setup, then we want to go ahead and trigger\n@@ -70,14 +82,8 @@\n     vendored(\"requests.packages.urllib3.connection\")\n     vendored(\"requests.packages.urllib3.connectionpool\")\n     vendored(\"requests.packages.urllib3.contrib\")\n-    try:\n-        vendored(\"requests.packages.urllib3.contrib.ntlmpool\")\n-    except ImportError:\n-        pass\n-    try:\n-        vendored(\"requests.packages.urllib3.contrib.pyopenssl\")\n-    except ImportError:\n-        pass\n+    vendored(\"requests.packages.urllib3.contrib.ntlmpool\")\n+    vendored(\"requests.packages.urllib3.contrib.pyopenssl\")\n     vendored(\"requests.packages.urllib3.exceptions\")\n     vendored(\"requests.packages.urllib3.fields\")\n     vendored(\"requests.packages.urllib3.filepost\")\n", "issue": "Protect a few more requests imports\nIn Debian, we unbundle requests, and further, we unbundled all vendored packages from requests.  This causes pip's vendoring algorithm to fail.  I had to add this patch to the Debian packaging.\n\n```\nFrom 144ba146cde273b815a80859537b09c068fd47e6 Mon Sep 17 00:00:00 2001\nFrom: Barry Warsaw <barry@python.org>\nDate: Fri, 29 Jan 2016 16:56:43 -0500\nSubject: Debian already unbundles things from requests.\n\nPatch-Name: handle-unbundled-requests.patch\n\n---\n pip/_vendor/__init__.py | 8 ++++++--\n 1 file changed, 6 insertions(+), 2 deletions(-)\n\ndiff --git a/pip/_vendor/__init__.py b/pip/_vendor/__init__.py\nindex 1cb35a1..c64896a 100644\n--- a/pip/_vendor/__init__.py\n+++ b/pip/_vendor/__init__.py\n@@ -82,8 +82,12 @@ if DEBUNDLED:\n     vendored(\"requests.packages.urllib3.fields\")\n     vendored(\"requests.packages.urllib3.filepost\")\n     vendored(\"requests.packages.urllib3.packages\")\n-    vendored(\"requests.packages.urllib3.packages.ordered_dict\")\n-    vendored(\"requests.packages.urllib3.packages.six\")\n+    try:\n+        vendored(\"requests.packages.urllib3.packages.ordered_dict\")\n+        vendored(\"requests.packages.urllib3.packages.six\")\n+    except ImportError:\n+        # Debian already unbundles these from requests.\n+        pass\n     vendored(\"requests.packages.urllib3.packages.ssl_match_hostname\")\n     vendored(\"requests.packages.urllib3.packages.ssl_match_hostname.\"\n              \"_implementation\")\n```\n\n", "before_files": [{"content": "\"\"\"\npip._vendor is for vendoring dependencies of pip to prevent needing pip to\ndepend on something external.\n\nFiles inside of pip._vendor should be considered immutable and should only be\nupdated to versions from upstream.\n\"\"\"\nfrom __future__ import absolute_import\n\nimport glob\nimport os.path\nimport sys\n\n# Downstream redistributors which have debundled our dependencies should also\n# patch this value to be true. This will trigger the additional patching\n# to cause things like \"six\" to be available as pip.\nDEBUNDLED = False\n\n# By default, look in this directory for a bunch of .whl files which we will\n# add to the beginning of sys.path before attempting to import anything. This\n# is done to support downstream re-distributors like Debian and Fedora who\n# wish to create their own Wheels for our dependencies to aid in debundling.\nWHEEL_DIR = os.path.abspath(os.path.dirname(__file__))\n\n\n# Define a small helper function to alias our vendored modules to the real ones\n# if the vendored ones do not exist. This idea of this was taken from\n# https://github.com/kennethreitz/requests/pull/2567.\ndef vendored(modulename):\n    vendored_name = \"{0}.{1}\".format(__name__, modulename)\n\n    try:\n        __import__(vendored_name, globals(), locals(), level=0)\n    except ImportError:\n        __import__(modulename, globals(), locals(), level=0)\n        sys.modules[vendored_name] = sys.modules[modulename]\n        base, head = vendored_name.rsplit(\".\", 1)\n        setattr(sys.modules[base], head, sys.modules[modulename])\n\n\n# If we're operating in a debundled setup, then we want to go ahead and trigger\n# the aliasing of our vendored libraries as well as looking for wheels to add\n# to our sys.path. This will cause all of this code to be a no-op typically\n# however downstream redistributors can enable it in a consistent way across\n# all platforms.\nif DEBUNDLED:\n    # Actually look inside of WHEEL_DIR to find .whl files and add them to the\n    # front of our sys.path.\n    sys.path[:] = glob.glob(os.path.join(WHEEL_DIR, \"*.whl\")) + sys.path\n\n    # Actually alias all of our vendored dependencies.\n    vendored(\"cachecontrol\")\n    vendored(\"colorama\")\n    vendored(\"distlib\")\n    vendored(\"html5lib\")\n    vendored(\"lockfile\")\n    vendored(\"six\")\n    vendored(\"six.moves\")\n    vendored(\"six.moves.urllib\")\n    vendored(\"packaging\")\n    vendored(\"packaging.version\")\n    vendored(\"packaging.specifiers\")\n    vendored(\"pkg_resources\")\n    vendored(\"progress\")\n    vendored(\"retrying\")\n    vendored(\"requests\")\n    vendored(\"requests.packages\")\n    vendored(\"requests.packages.urllib3\")\n    vendored(\"requests.packages.urllib3._collections\")\n    vendored(\"requests.packages.urllib3.connection\")\n    vendored(\"requests.packages.urllib3.connectionpool\")\n    vendored(\"requests.packages.urllib3.contrib\")\n    try:\n        vendored(\"requests.packages.urllib3.contrib.ntlmpool\")\n    except ImportError:\n        pass\n    try:\n        vendored(\"requests.packages.urllib3.contrib.pyopenssl\")\n    except ImportError:\n        pass\n    vendored(\"requests.packages.urllib3.exceptions\")\n    vendored(\"requests.packages.urllib3.fields\")\n    vendored(\"requests.packages.urllib3.filepost\")\n    vendored(\"requests.packages.urllib3.packages\")\n    vendored(\"requests.packages.urllib3.packages.ordered_dict\")\n    vendored(\"requests.packages.urllib3.packages.six\")\n    vendored(\"requests.packages.urllib3.packages.ssl_match_hostname\")\n    vendored(\"requests.packages.urllib3.packages.ssl_match_hostname.\"\n             \"_implementation\")\n    vendored(\"requests.packages.urllib3.poolmanager\")\n    vendored(\"requests.packages.urllib3.request\")\n    vendored(\"requests.packages.urllib3.response\")\n    vendored(\"requests.packages.urllib3.util\")\n    vendored(\"requests.packages.urllib3.util.connection\")\n    vendored(\"requests.packages.urllib3.util.request\")\n    vendored(\"requests.packages.urllib3.util.response\")\n    vendored(\"requests.packages.urllib3.util.retry\")\n    vendored(\"requests.packages.urllib3.util.ssl_\")\n    vendored(\"requests.packages.urllib3.util.timeout\")\n    vendored(\"requests.packages.urllib3.util.url\")\n", "path": "pip/_vendor/__init__.py"}], "after_files": [{"content": "\"\"\"\npip._vendor is for vendoring dependencies of pip to prevent needing pip to\ndepend on something external.\n\nFiles inside of pip._vendor should be considered immutable and should only be\nupdated to versions from upstream.\n\"\"\"\nfrom __future__ import absolute_import\n\nimport glob\nimport os.path\nimport sys\n\n# Downstream redistributors which have debundled our dependencies should also\n# patch this value to be true. This will trigger the additional patching\n# to cause things like \"six\" to be available as pip.\nDEBUNDLED = False\n\n# By default, look in this directory for a bunch of .whl files which we will\n# add to the beginning of sys.path before attempting to import anything. This\n# is done to support downstream re-distributors like Debian and Fedora who\n# wish to create their own Wheels for our dependencies to aid in debundling.\nWHEEL_DIR = os.path.abspath(os.path.dirname(__file__))\n\n\n# Define a small helper function to alias our vendored modules to the real ones\n# if the vendored ones do not exist. This idea of this was taken from\n# https://github.com/kennethreitz/requests/pull/2567.\ndef vendored(modulename):\n    vendored_name = \"{0}.{1}\".format(__name__, modulename)\n\n    try:\n        __import__(vendored_name, globals(), locals(), level=0)\n    except ImportError:\n        try:\n            __import__(modulename, globals(), locals(), level=0)\n        except ImportError:\n            # We can just silently allow import failures to pass here. If we\n            # got to this point it means that ``import pip._vendor.whatever``\n            # failed and so did ``import whatever``. Since we're importing this\n            # upfront in an attempt to alias imports, not erroring here will\n            # just mean we get a regular import error whenever pip *actually*\n            # tries to import one of these modules to use it, which actually\n            # gives us a better error message than we would have otherwise\n            # gotten.\n            pass\n        else:\n            sys.modules[vendored_name] = sys.modules[modulename]\n            base, head = vendored_name.rsplit(\".\", 1)\n            setattr(sys.modules[base], head, sys.modules[modulename])\n\n\n# If we're operating in a debundled setup, then we want to go ahead and trigger\n# the aliasing of our vendored libraries as well as looking for wheels to add\n# to our sys.path. This will cause all of this code to be a no-op typically\n# however downstream redistributors can enable it in a consistent way across\n# all platforms.\nif DEBUNDLED:\n    # Actually look inside of WHEEL_DIR to find .whl files and add them to the\n    # front of our sys.path.\n    sys.path[:] = glob.glob(os.path.join(WHEEL_DIR, \"*.whl\")) + sys.path\n\n    # Actually alias all of our vendored dependencies.\n    vendored(\"cachecontrol\")\n    vendored(\"colorama\")\n    vendored(\"distlib\")\n    vendored(\"html5lib\")\n    vendored(\"lockfile\")\n    vendored(\"six\")\n    vendored(\"six.moves\")\n    vendored(\"six.moves.urllib\")\n    vendored(\"packaging\")\n    vendored(\"packaging.version\")\n    vendored(\"packaging.specifiers\")\n    vendored(\"pkg_resources\")\n    vendored(\"progress\")\n    vendored(\"retrying\")\n    vendored(\"requests\")\n    vendored(\"requests.packages\")\n    vendored(\"requests.packages.urllib3\")\n    vendored(\"requests.packages.urllib3._collections\")\n    vendored(\"requests.packages.urllib3.connection\")\n    vendored(\"requests.packages.urllib3.connectionpool\")\n    vendored(\"requests.packages.urllib3.contrib\")\n    vendored(\"requests.packages.urllib3.contrib.ntlmpool\")\n    vendored(\"requests.packages.urllib3.contrib.pyopenssl\")\n    vendored(\"requests.packages.urllib3.exceptions\")\n    vendored(\"requests.packages.urllib3.fields\")\n    vendored(\"requests.packages.urllib3.filepost\")\n    vendored(\"requests.packages.urllib3.packages\")\n    vendored(\"requests.packages.urllib3.packages.ordered_dict\")\n    vendored(\"requests.packages.urllib3.packages.six\")\n    vendored(\"requests.packages.urllib3.packages.ssl_match_hostname\")\n    vendored(\"requests.packages.urllib3.packages.ssl_match_hostname.\"\n             \"_implementation\")\n    vendored(\"requests.packages.urllib3.poolmanager\")\n    vendored(\"requests.packages.urllib3.request\")\n    vendored(\"requests.packages.urllib3.response\")\n    vendored(\"requests.packages.urllib3.util\")\n    vendored(\"requests.packages.urllib3.util.connection\")\n    vendored(\"requests.packages.urllib3.util.request\")\n    vendored(\"requests.packages.urllib3.util.response\")\n    vendored(\"requests.packages.urllib3.util.retry\")\n    vendored(\"requests.packages.urllib3.util.ssl_\")\n    vendored(\"requests.packages.urllib3.util.timeout\")\n    vendored(\"requests.packages.urllib3.util.url\")\n", "path": "pip/_vendor/__init__.py"}]}