From b959ea476879582717c50b97efeb483842a2d911 Mon Sep 17 00:00:00 2001
From: Kenneth Reitz <me@kennethreitz.org>
Date: Wed, 13 Sep 2017 12:11:48 -0400
Subject: [PATCH] default version of python in pipfile

Signed-off-by: Kenneth Reitz <me@kennethreitz.org>
---
 pipenv/cli.py     | 37 ++++++++++++++++---------------------
 pipenv/project.py | 40 ++++++++++++++++++++++++++++++++++++----
 pipenv/utils.py   | 15 +++++++++++++++
 3 files changed, 67 insertions(+), 25 deletions(-)

diff --git a/pipenv/cli.py b/pipenv/cli.py
index 40df4e06..89b40bc7 100644
--- a/pipenv/cli.py
+++ b/pipenv/cli.py
@@ -29,7 +29,8 @@ from pip.req.req_file import parse_requirements
 from .project import Project
 from .utils import (
     convert_deps_from_pip, convert_deps_to_pip, is_required_version,
-    proper_case, pep423_name, split_vcs, resolve_deps, shellquote, is_vcs
+    proper_case, pep423_name, split_vcs, resolve_deps, shellquote, is_vcs,
+    python_version
 )
 from .__version__ import __version__
 from . import pep508checker, progress
@@ -234,14 +235,14 @@ def ensure_pipfile(validate=True):
     """Creates a Pipfile for the project, if it doesn't exist."""
 
     # Assert Pipfile exists.
-    if not project.pipfile_exists:
+    if project.pipfile_is_empty:
 
         # If there's a requirements file, but no Pipfile...
         if project.requirements_exists:
             click.echo(crayons.white(u'Requirements.txt found, instead of Pipfile! Converting…', bold=True))
 
             # Create a Pipfile...
-            project.create_pipfile()
+            project.create_pipfile(python=which('python'))
 
             # Import requirements.txt.
             import_requirements()
@@ -249,7 +250,7 @@ def ensure_pipfile(validate=True):
         else:
             click.echo(crayons.white(u'Creating a Pipfile for this project…', bold=True), err=True)
             # Create the pipfile if it doesn't exist.
-            project.create_pipfile()
+            project.create_pipfile(python=which('python'))
 
     # Validate the Pipfile's contents.
     if validate and project.virtualenv_exists and not PIPENV_SKIP_VALIDATION:
@@ -263,16 +264,6 @@ def ensure_pipfile(validate=True):
             project.write_toml(p)
 
 
-def python_version(path_to_python):
-    try:
-        c = delegator.run('{0} --version'.format(path_to_python), block=False)
-        c.return_code == 0
-    except Exception:
-        return None
-
-    return str(c.out.strip() or c.err.strip())
-
-
 def find_a_system_python(python):
     if python.startswith('py'):
         return system_which(python)
@@ -352,7 +343,7 @@ def ensure_virtualenv(three=None, python=None):
 def ensure_project(three=None, python=None, validate=True, system=False, warn=True):
     """Ensures both Pipfile and virtualenv exist for the project."""
 
-    ensure_pipfile(validate=validate)
+    project.touch_pipfile()
 
     # Skip virtualenv creation when --system was used.
     if not system:
@@ -378,6 +369,9 @@ def ensure_project(three=None, python=None, validate=True, system=False, warn=Tr
                         ''.format(crayons.red('$ pipenv check'))
                     )
 
+    # Ensure the Pipfile exists.
+    ensure_pipfile(validate=validate)
+
 
 def ensure_proper_casing(pfile):
     """Ensures proper casing of Pipfile packages, writes changes to disk."""
@@ -846,12 +840,6 @@ def do_init(
 ):
     """Executes the init functionality."""
 
-    ensure_pipfile()
-
-    # Display where the Project is established.
-    if not requirements:
-        do_where(bare=False)
-
     if not project.virtualenv_exists:
         try:
             do_create_virtualenv()
@@ -859,6 +847,13 @@ def do_init(
             cleanup_virtualenv(bare=False)
             sys.exit(1)
 
+    # Ensure the Pipfile exists.
+    ensure_pipfile()
+
+    # Display where the Project is established.
+    if not requirements:
+        do_where(bare=False)
+
     # Write out the lockfile if it doesn't exist, but not if the Pipfile is being ignored
     if (project.lockfile_exists and not ignore_pipfile) and not skip_lock:
 
diff --git a/pipenv/project.py b/pipenv/project.py
index e496844a..451248f2 100644
--- a/pipenv/project.py
+++ b/pipenv/project.py
@@ -14,7 +14,7 @@ from requests.compat import OrderedDict
 
 from .utils import (
     format_toml, mkdir_p, convert_deps_from_pip, pep423_name, recase_file,
-    find_requirements, is_file, is_vcs
+    find_requirements, is_file, is_vcs, python_version
 )
 from .environments import PIPENV_MAX_DEPTH, PIPENV_VENV_IN_PROJECT
 from .environments import PIPENV_USE_SYSTEM
@@ -52,7 +52,9 @@ class Project(object):
     @property
     def required_python_version(self):
         if self.pipfile_exists:
-            return self.parsed_pipfile.get('requires', {}).get('python_version')
+            required = self.parsed_pipfile.get('requires', {}).get('python_version')
+            if required != "*":
+                return required
 
     @property
     def project_directory(self):
@@ -254,11 +256,41 @@ class Project(object):
                 ps.update({k: v})
         return ps
 
-    def create_pipfile(self):
-        data = {u'source': [{u'url': u'https://pypi.python.org/simple', u'verify_ssl': True}], u'packages': {}, 'dev-packages': {}}
+    def touch_pipfile(self):
+        """Simply touches the Pipfile, for later use."""
+        with open('Pipfile', 'a'):
+            os.utime('Pipfile', None)
+
+    @property
+    def pipfile_is_empty(self):
+        self.touch_pipfile()
+
+        with open('Pipfile', 'r') as f:
+            if not f.read():
+                return True
+
+    def create_pipfile(self, python=None):
+        """Creates the Pipfile, filled with juicy defaults."""
+        data = {
+            # Default source.
+            u'source': [
+                {u'url': u'https://pypi.python.org/simple', u'verify_ssl': True}
+            ],
+
+            # Default packages.
+            u'packages': {},
+            u'dev-packages': {},
+
+            # Default requires.
+        }
+
+        if python:
+            data[u'requires'] = {'python_version': python_version(python)[:len('2.7')]}
+
         self.write_toml(data, 'Pipfile')
 
     def write_toml(self, data, path=None):
+        """Writes the given data structure out as TOML."""
         if path is None:
             path = self.pipfile_location
 
diff --git a/pipenv/utils.py b/pipenv/utils.py
index 98e42f6e..d2828e69 100644
--- a/pipenv/utils.py
+++ b/pipenv/utils.py
@@ -8,6 +8,7 @@ from piptools.repositories.pypi import PyPIRepository
 from piptools.scripts.compile import get_pip_command
 from piptools import logging
 
+import delegator
 import requests
 import parse
 import pip
@@ -25,6 +26,20 @@ class PipCommand(pip.basecommand.Command):
     name = 'PipCommand'
 
 
+def python_version(path_to_python):
+    try:
+        TEMPLATE = 'Python {}.{}.{}'
+        c = delegator.run('{0} --version'.format(path_to_python), block=False)
+        c.return_code == 0
+    except Exception:
+        return None
+
+    output = c.out.strip() or c.err.strip()
+    parsed = parse.parse(TEMPLATE, output).fixed
+
+    return u"{v[0]}.{v[1]}.{v[2]}".format(v=parsed)
+
+
 def shellquote(s):
     """Prepares a string for the shell (on Windows too!)"""
     return '"' + s.replace("'", "'\\''") + '"'