From 4a15f3b1c1332f6f6b4150feb7502ab94e48a6d7 Mon Sep 17 00:00:00 2001
From: Tzu-ping Chung <uranusjr@gmail.com>
Date: Fri, 13 Apr 2018 00:04:03 +0800
Subject: [PATCH 1/4] Make sure --version succeeds

And make sure what it returns makes sense. In case it isn't, return None.
---
 pipenv/utils.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pipenv/utils.py b/pipenv/utils.py
index 832105fa..e3eba96e 100644
--- a/pipenv/utils.py
+++ b/pipenv/utils.py
@@ -220,7 +220,11 @@ def python_version(path_to_python):
         c = delegator.run([path_to_python, '--version'], block=False)
     except Exception:
         return None
+    if c.return_code != 0:
+        return None
     version = parse_python_version(c.out.strip() or c.err.strip())
+    if not version:
+        return None
     return u'{major}.{minor}.{micro}'.format(**version)
 
 

From 5b2db86fa9390251c3b5a5b4a8d3bae3e613a19b Mon Sep 17 00:00:00 2001
From: Tzu-ping Chung <uranusjr@gmail.com>
Date: Fri, 13 Apr 2018 00:10:45 +0800
Subject: [PATCH 2/4] Add a trivial test for help

---
 tests/unit/test_help.py | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 tests/unit/test_help.py

diff --git a/tests/unit/test_help.py b/tests/unit/test_help.py
new file mode 100644
index 00000000..c48e76d3
--- /dev/null
+++ b/tests/unit/test_help.py
@@ -0,0 +1,10 @@
+import subprocess
+import sys
+
+
+def test_help():
+    output = subprocess.check_output(
+        [sys.executable, '-m', 'pipenv.help'],
+        stderr=subprocess.STDOUT,
+    )
+    assert output

From 3fa64125c270b5abddad337657397d89a8e2c757 Mon Sep 17 00:00:00 2001
From: Dan Ryan <dan@danryan.co>
Date: Thu, 12 Apr 2018 18:43:05 -0400
Subject: [PATCH 3/4] Fix `create_pipfile` version parsing

Signed-off-by: Dan Ryan <dan@danryan.co>
---
 pipenv/project.py | 18 ++++++++++++------
 pipenv/utils.py   |  9 +++++----
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/pipenv/project.py b/pipenv/project.py
index 46bf8103..642dc519 100644
--- a/pipenv/project.py
+++ b/pipenv/project.py
@@ -44,6 +44,7 @@ from .environments import (
     PIPENV_VIRTUALENV,
     PIPENV_TEST_INDEX,
     PIPENV_PYTHON,
+    PIPENV_DEFAULT_PYTHON_VERSION,
 )
 
 
@@ -578,12 +579,17 @@ class Project(object):
             u'dev-packages': {},
         }
         # Default requires.
-        required_python = python or self.which(
-            'python', self.virtualenv_location
-        )
-        data[u'requires'] = {
-            'python_version': python_version(required_python)[: len('2.7')]
-        }
+        required_python = python
+        if not python:
+            if self.virtualenv_location:
+                required_python = self.which('python', self.virtualenv_location)
+            else:
+                required_python = self.which('python')
+        version = python_version(required_python) or PIPENV_DEFAULT_PYTHON_VERSION
+        if version and len(version) >= 3:
+            data[u'requires'] = {
+                'python_version': version[: len('2.7')]
+            }
         self.write_toml(data, 'Pipfile')
 
     def write_toml(self, data, path=None):
diff --git a/pipenv/utils.py b/pipenv/utils.py
index e3eba96e..4a4ce008 100644
--- a/pipenv/utils.py
+++ b/pipenv/utils.py
@@ -220,12 +220,13 @@ def python_version(path_to_python):
         c = delegator.run([path_to_python, '--version'], block=False)
     except Exception:
         return None
-    if c.return_code != 0:
-        return None
+    c.block()
     version = parse_python_version(c.out.strip() or c.err.strip())
-    if not version:
+    try:
+        version = u'{major}.{minor}.{micro}'.format(**version)
+    except TypeError:
         return None
-    return u'{major}.{minor}.{micro}'.format(**version)
+    return version
 
 
 def escape_grouped_arguments(s):

From cf3c5611005e9b9a5ffda54de959aed588a19af3 Mon Sep 17 00:00:00 2001
From: Dan Ryan <dan@danryan.co>
Date: Thu, 12 Apr 2018 19:41:01 -0400
Subject: [PATCH 4/4] Pass environment to subprocess

- `check_output` needs to pass `PYTHONIOENCODING` to `Popen` on python2

Signed-off-by: Dan Ryan <dan@danryan.co>
---
 tests/unit/test_help.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/unit/test_help.py b/tests/unit/test_help.py
index c48e76d3..2432e969 100644
--- a/tests/unit/test_help.py
+++ b/tests/unit/test_help.py
@@ -1,3 +1,4 @@
+import os
 import subprocess
 import sys
 
@@ -5,6 +6,6 @@ import sys
 def test_help():
     output = subprocess.check_output(
         [sys.executable, '-m', 'pipenv.help'],
-        stderr=subprocess.STDOUT,
+        stderr=subprocess.STDOUT, env=os.environ.copy(),
     )
     assert output