Fixed #18224 -- Changed the dev version number.

Following the move from SVN to git.

django/__init__.py

@@ -1,5 +1,11 @@
+import datetime
+import os
+import subprocess
+
+
 VERSION = (1, 5, 0, 'alpha', 0)
 
+
 def get_version(version=None):
     """Derives a PEP386-compliant version number from VERSION."""
     if version is None:
@@ -17,14 +23,31 @@ def get_version(version=None):
 
     sub = ''
     if version[3] == 'alpha' and version[4] == 0:
-        # At the toplevel, this would cause an import loop.
-        from django.utils.version import get_svn_revision
-        svn_revision = get_svn_revision()[4:]
-        if svn_revision != 'unknown':
-            sub = '.dev%s' % svn_revision
+        git_changeset = get_git_changeset()
+        if git_changeset:
+            sub = '.dev%s' % git_changeset
 
     elif version[3] != 'final':
         mapping = {'alpha': 'a', 'beta': 'b', 'rc': 'c'}
         sub = mapping[version[3]] + str(version[4])
 
     return main + sub
+
+
+def get_git_changeset():
+    """Returns a numeric identifier of the latest git changeset.
+
+    The result is the UTC timestamp of the changeset in YYYYMMDDHHMMSS format.
+    This value isn't guaranteed to be unique but collisions are very unlikely,
+    so it's sufficient for generating the development version numbers.
+    """
+    repo_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+    git_show = subprocess.Popen('git show --pretty=format:%ct --quiet HEAD',
+            stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+            shell=True, cwd=repo_dir, universal_newlines=True)
+    timestamp = git_show.communicate()[0].partition('\n')[0]
+    try:
+        timestamp = datetime.datetime.utcfromtimestamp(int(timestamp))
+    except ValueError:
+        return None
+    return timestamp.strftime('%Y%m%d%H%M%S')