We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Selfcheck failure on Windows
I get this warning all the time:

```
There was an error checking the latest version of pip
Traceback (most recent call last):
  File "C:\Python27\lib\site-packages\pip\utils\outdated.py", line 115, in pip_version_check
    state.save(pypi_version, current_time)
  File "C:\Python27\lib\site-packages\pip\utils\outdated.py", line 62, in save
    with open(self.statefile_path) as statefile:
IOError: [Errno 2] No such file or directory: u'C:\\Users\\ionel_000\\AppData\\Local\\pip\\Cache\\selfcheck.json'
```

If I create the file, it complains about invalid json. I've put `{}` inside, the warning has gone away, but this seems very wrong to me.


--- 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Path: `pip/utils/outdated.py`
Content:
```
1 from __future__ import absolute_import
2 
3 import datetime
4 import json
5 import logging
6 import os.path
7 import sys
8 
9 from pip._vendor import lockfile
10 from pip._vendor import pkg_resources
11 
12 from pip.compat import total_seconds
13 from pip.index import PyPI
14 from pip.locations import USER_CACHE_DIR, running_under_virtualenv
15 
16 
17 SELFCHECK_DATE_FMT = "%Y-%m-%dT%H:%M:%SZ"
18 
19 
20 logger = logging.getLogger(__name__)
21 
22 
23 class VirtualenvSelfCheckState(object):
24     def __init__(self):
25         self.statefile_path = os.path.join(sys.prefix, "pip-selfcheck.json")
26 
27         # Load the existing state
28         try:
29             with open(self.statefile_path) as statefile:
30                 self.state = json.load(statefile)
31         except (IOError, ValueError):
32             self.state = {}
33 
34     def save(self, pypi_version, current_time):
35         # Attempt to write out our version check file
36         with open(self.statefile_path, "w") as statefile:
37             json.dump(
38                 {
39                     "last_check": current_time.strftime(SELFCHECK_DATE_FMT),
40                     "pypi_version": pypi_version,
41                 },
42                 statefile,
43                 sort_keys=True,
44                 separators=(",", ":")
45             )
46 
47 
48 class GlobalSelfCheckState(object):
49     def __init__(self):
50         self.statefile_path = os.path.join(USER_CACHE_DIR, "selfcheck.json")
51 
52         # Load the existing state
53         try:
54             with open(self.statefile_path) as statefile:
55                 self.state = json.load(statefile)[sys.prefix]
56         except (IOError, ValueError, KeyError):
57             self.state = {}
58 
59     def save(self, pypi_version, current_time):
60         # Attempt to write out our version check file
61         with lockfile.LockFile(self.statefile_path):
62             with open(self.statefile_path) as statefile:
63                 state = json.load(statefile)
64 
65             state[sys.prefix] = {
66                 "last_check": current_time.strftime(SELFCHECK_DATE_FMT),
67                 "pypi_version": pypi_version,
68             }
69 
70             with open(self.statefile_path, "w") as statefile:
71                 json.dump(state, statefile, sort_keys=True,
72                           separators=(",", ":"))
73 
74 
75 def load_selfcheck_statefile():
76     if running_under_virtualenv():
77         return VirtualenvSelfCheckState()
78     else:
79         return GlobalSelfCheckState()
80 
81 
82 def pip_version_check(session):
83     """Check for an update for pip.
84 
85     Limit the frequency of checks to once per week. State is stored either in
86     the active virtualenv or in the user's USER_CACHE_DIR keyed off the prefix
87     of the pip script path.
88     """
89     import pip  # imported here to prevent circular imports
90     pypi_version = None
91 
92     try:
93         state = load_selfcheck_statefile()
94 
95         current_time = datetime.datetime.utcnow()
96         # Determine if we need to refresh the state
97         if "last_check" in state.state and "pypi_version" in state.state:
98             last_check = datetime.datetime.strptime(
99                 state.state["last_check"],
100                 SELFCHECK_DATE_FMT
101             )
102             if total_seconds(current_time - last_check) < 7 * 24 * 60 * 60:
103                 pypi_version = state.state["pypi_version"]
104 
105         # Refresh the version if we need to or just see if we need to warn
106         if pypi_version is None:
107             resp = session.get(
108                 PyPI.pip_json_url,
109                 headers={"Accept": "application/json"},
110             )
111             resp.raise_for_status()
112             pypi_version = resp.json()["info"]["version"]
113 
114             # save that we've performed a check
115             state.save(pypi_version, current_time)
116 
117         pip_version = pkg_resources.parse_version(pip.__version__)
118 
119         # Determine if our pypi_version is older
120         if pip_version < pkg_resources.parse_version(pypi_version):
121             logger.warning(
122                 "You are using pip version %s, however version %s is "
123                 "available.\nYou should consider upgrading via the "
124                 "'pip install --upgrade pip' command." % (pip.__version__,
125                                                           pypi_version)
126             )
127 
128     except Exception:
129         logger.debug(
130             "There was an error checking the latest version of pip",
131             exc_info=True,
132         )
133
```
--- 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/utils/outdated.py b/pip/utils/outdated.py
--- a/pip/utils/outdated.py
+++ b/pip/utils/outdated.py
@@ -1,6 +1,7 @@
 from __future__ import absolute_import
 
 import datetime
+import errno
 import json
 import logging
 import os.path
@@ -12,6 +13,7 @@
 from pip.compat import total_seconds
 from pip.index import PyPI
 from pip.locations import USER_CACHE_DIR, running_under_virtualenv
+from pip.utils.filesystem import check_path_owner
 
 
 SELFCHECK_DATE_FMT = "%Y-%m-%dT%H:%M:%SZ"
@@ -57,6 +59,19 @@
             self.state = {}
 
     def save(self, pypi_version, current_time):
+        # Check to make sure that we own the directory
+        if not check_path_owner(
+                os.path.dirname(self.statefile_path), os.geteuid()):
+            return
+
+        # Now that we've ensured the directory is owned by this user, we'll go
+        # ahead and make sure that all our directories are created.
+        try:
+            os.makedirs(os.path.dirname(self.statefile_path))
+        except OSError as exc:
+            if exc.errno != errno.EEXIST:
+                raise
+
         # Attempt to write out our version check file
         with lockfile.LockFile(self.statefile_path):
             with open(self.statefile_path) as statefile:

{"golden_diff": "diff --git a/pip/utils/outdated.py b/pip/utils/outdated.py\n--- a/pip/utils/outdated.py\n+++ b/pip/utils/outdated.py\n@@ -1,6 +1,7 @@\n from __future__ import absolute_import\n \n import datetime\n+import errno\n import json\n import logging\n import os.path\n@@ -12,6 +13,7 @@\n from pip.compat import total_seconds\n from pip.index import PyPI\n from pip.locations import USER_CACHE_DIR, running_under_virtualenv\n+from pip.utils.filesystem import check_path_owner\n \n \n SELFCHECK_DATE_FMT = \"%Y-%m-%dT%H:%M:%SZ\"\n@@ -57,6 +59,19 @@\n             self.state = {}\n \n     def save(self, pypi_version, current_time):\n+        # Check to make sure that we own the directory\n+        if not check_path_owner(\n+                os.path.dirname(self.statefile_path), os.geteuid()):\n+            return\n+\n+        # Now that we've ensured the directory is owned by this user, we'll go\n+        # ahead and make sure that all our directories are created.\n+        try:\n+            os.makedirs(os.path.dirname(self.statefile_path))\n+        except OSError as exc:\n+            if exc.errno != errno.EEXIST:\n+                raise\n+\n         # Attempt to write out our version check file\n         with lockfile.LockFile(self.statefile_path):\n             with open(self.statefile_path) as statefile:\n", "issue": "Selfcheck failure on Windows\nI get this warning all the time:\n\n```\nThere was an error checking the latest version of pip\nTraceback (most recent call last):\n  File \"C:\\Python27\\lib\\site-packages\\pip\\utils\\outdated.py\", line 115, in pip_version_check\n    state.save(pypi_version, current_time)\n  File \"C:\\Python27\\lib\\site-packages\\pip\\utils\\outdated.py\", line 62, in save\n    with open(self.statefile_path) as statefile:\nIOError: [Errno 2] No such file or directory: u'C:\\\\Users\\\\ionel_000\\\\AppData\\\\Local\\\\pip\\\\Cache\\\\selfcheck.json'\n```\n\nIf I create the file, it complains about invalid json. I've put `{}` inside, the warning has gone away, but this seems very wrong to me.\n\n", "before_files": [{"content": "from __future__ import absolute_import\n\nimport datetime\nimport json\nimport logging\nimport os.path\nimport sys\n\nfrom pip._vendor import lockfile\nfrom pip._vendor import pkg_resources\n\nfrom pip.compat import total_seconds\nfrom pip.index import PyPI\nfrom pip.locations import USER_CACHE_DIR, running_under_virtualenv\n\n\nSELFCHECK_DATE_FMT = \"%Y-%m-%dT%H:%M:%SZ\"\n\n\nlogger = logging.getLogger(__name__)\n\n\nclass VirtualenvSelfCheckState(object):\n    def __init__(self):\n        self.statefile_path = os.path.join(sys.prefix, \"pip-selfcheck.json\")\n\n        # Load the existing state\n        try:\n            with open(self.statefile_path) as statefile:\n                self.state = json.load(statefile)\n        except (IOError, ValueError):\n            self.state = {}\n\n    def save(self, pypi_version, current_time):\n        # Attempt to write out our version check file\n        with open(self.statefile_path, \"w\") as statefile:\n            json.dump(\n                {\n                    \"last_check\": current_time.strftime(SELFCHECK_DATE_FMT),\n                    \"pypi_version\": pypi_version,\n                },\n                statefile,\n                sort_keys=True,\n                separators=(\",\", \":\")\n            )\n\n\nclass GlobalSelfCheckState(object):\n    def __init__(self):\n        self.statefile_path = os.path.join(USER_CACHE_DIR, \"selfcheck.json\")\n\n        # Load the existing state\n        try:\n            with open(self.statefile_path) as statefile:\n                self.state = json.load(statefile)[sys.prefix]\n        except (IOError, ValueError, KeyError):\n            self.state = {}\n\n    def save(self, pypi_version, current_time):\n        # Attempt to write out our version check file\n        with lockfile.LockFile(self.statefile_path):\n            with open(self.statefile_path) as statefile:\n                state = json.load(statefile)\n\n            state[sys.prefix] = {\n                \"last_check\": current_time.strftime(SELFCHECK_DATE_FMT),\n                \"pypi_version\": pypi_version,\n            }\n\n            with open(self.statefile_path, \"w\") as statefile:\n                json.dump(state, statefile, sort_keys=True,\n                          separators=(\",\", \":\"))\n\n\ndef load_selfcheck_statefile():\n    if running_under_virtualenv():\n        return VirtualenvSelfCheckState()\n    else:\n        return GlobalSelfCheckState()\n\n\ndef pip_version_check(session):\n    \"\"\"Check for an update for pip.\n\n    Limit the frequency of checks to once per week. State is stored either in\n    the active virtualenv or in the user's USER_CACHE_DIR keyed off the prefix\n    of the pip script path.\n    \"\"\"\n    import pip  # imported here to prevent circular imports\n    pypi_version = None\n\n    try:\n        state = load_selfcheck_statefile()\n\n        current_time = datetime.datetime.utcnow()\n        # Determine if we need to refresh the state\n        if \"last_check\" in state.state and \"pypi_version\" in state.state:\n            last_check = datetime.datetime.strptime(\n                state.state[\"last_check\"],\n                SELFCHECK_DATE_FMT\n            )\n            if total_seconds(current_time - last_check) < 7 * 24 * 60 * 60:\n                pypi_version = state.state[\"pypi_version\"]\n\n        # Refresh the version if we need to or just see if we need to warn\n        if pypi_version is None:\n            resp = session.get(\n                PyPI.pip_json_url,\n                headers={\"Accept\": \"application/json\"},\n            )\n            resp.raise_for_status()\n            pypi_version = resp.json()[\"info\"][\"version\"]\n\n            # save that we've performed a check\n            state.save(pypi_version, current_time)\n\n        pip_version = pkg_resources.parse_version(pip.__version__)\n\n        # Determine if our pypi_version is older\n        if pip_version < pkg_resources.parse_version(pypi_version):\n            logger.warning(\n                \"You are using pip version %s, however version %s is \"\n                \"available.\\nYou should consider upgrading via the \"\n                \"'pip install --upgrade pip' command.\" % (pip.__version__,\n                                                          pypi_version)\n            )\n\n    except Exception:\n        logger.debug(\n            \"There was an error checking the latest version of pip\",\n            exc_info=True,\n        )\n", "path": "pip/utils/outdated.py"}], "after_files": [{"content": "from __future__ import absolute_import\n\nimport datetime\nimport errno\nimport json\nimport logging\nimport os.path\nimport sys\n\nfrom pip._vendor import lockfile\nfrom pip._vendor import pkg_resources\n\nfrom pip.compat import total_seconds\nfrom pip.index import PyPI\nfrom pip.locations import USER_CACHE_DIR, running_under_virtualenv\nfrom pip.utils.filesystem import check_path_owner\n\n\nSELFCHECK_DATE_FMT = \"%Y-%m-%dT%H:%M:%SZ\"\n\n\nlogger = logging.getLogger(__name__)\n\n\nclass VirtualenvSelfCheckState(object):\n    def __init__(self):\n        self.statefile_path = os.path.join(sys.prefix, \"pip-selfcheck.json\")\n\n        # Load the existing state\n        try:\n            with open(self.statefile_path) as statefile:\n                self.state = json.load(statefile)\n        except (IOError, ValueError):\n            self.state = {}\n\n    def save(self, pypi_version, current_time):\n        # Attempt to write out our version check file\n        with open(self.statefile_path, \"w\") as statefile:\n            json.dump(\n                {\n                    \"last_check\": current_time.strftime(SELFCHECK_DATE_FMT),\n                    \"pypi_version\": pypi_version,\n                },\n                statefile,\n                sort_keys=True,\n                separators=(\",\", \":\")\n            )\n\n\nclass GlobalSelfCheckState(object):\n    def __init__(self):\n        self.statefile_path = os.path.join(USER_CACHE_DIR, \"selfcheck.json\")\n\n        # Load the existing state\n        try:\n            with open(self.statefile_path) as statefile:\n                self.state = json.load(statefile)[sys.prefix]\n        except (IOError, ValueError, KeyError):\n            self.state = {}\n\n    def save(self, pypi_version, current_time):\n        # Check to make sure that we own the directory\n        if not check_path_owner(\n                os.path.dirname(self.statefile_path), os.geteuid()):\n            return\n\n        # Now that we've ensured the directory is owned by this user, we'll go\n        # ahead and make sure that all our directories are created.\n        try:\n            os.makedirs(os.path.dirname(self.statefile_path))\n        except OSError as exc:\n            if exc.errno != errno.EEXIST:\n                raise\n\n        # Attempt to write out our version check file\n        with lockfile.LockFile(self.statefile_path):\n            with open(self.statefile_path) as statefile:\n                state = json.load(statefile)\n\n            state[sys.prefix] = {\n                \"last_check\": current_time.strftime(SELFCHECK_DATE_FMT),\n                \"pypi_version\": pypi_version,\n            }\n\n            with open(self.statefile_path, \"w\") as statefile:\n                json.dump(state, statefile, sort_keys=True,\n                          separators=(\",\", \":\"))\n\n\ndef load_selfcheck_statefile():\n    if running_under_virtualenv():\n        return VirtualenvSelfCheckState()\n    else:\n        return GlobalSelfCheckState()\n\n\ndef pip_version_check(session):\n    \"\"\"Check for an update for pip.\n\n    Limit the frequency of checks to once per week. State is stored either in\n    the active virtualenv or in the user's USER_CACHE_DIR keyed off the prefix\n    of the pip script path.\n    \"\"\"\n    import pip  # imported here to prevent circular imports\n    pypi_version = None\n\n    try:\n        state = load_selfcheck_statefile()\n\n        current_time = datetime.datetime.utcnow()\n        # Determine if we need to refresh the state\n        if \"last_check\" in state.state and \"pypi_version\" in state.state:\n            last_check = datetime.datetime.strptime(\n                state.state[\"last_check\"],\n                SELFCHECK_DATE_FMT\n            )\n            if total_seconds(current_time - last_check) < 7 * 24 * 60 * 60:\n                pypi_version = state.state[\"pypi_version\"]\n\n        # Refresh the version if we need to or just see if we need to warn\n        if pypi_version is None:\n            resp = session.get(\n                PyPI.pip_json_url,\n                headers={\"Accept\": \"application/json\"},\n            )\n            resp.raise_for_status()\n            pypi_version = resp.json()[\"info\"][\"version\"]\n\n            # save that we've performed a check\n            state.save(pypi_version, current_time)\n\n        pip_version = pkg_resources.parse_version(pip.__version__)\n\n        # Determine if our pypi_version is older\n        if pip_version < pkg_resources.parse_version(pypi_version):\n            logger.warning(\n                \"You are using pip version %s, however version %s is \"\n                \"available.\\nYou should consider upgrading via the \"\n                \"'pip install --upgrade pip' command.\" % (pip.__version__,\n                                                          pypi_version)\n            )\n\n    except Exception:\n        logger.debug(\n            \"There was an error checking the latest version of pip\",\n            exc_info=True,\n        )\n", "path": "pip/utils/outdated.py"}]}