Implemented PEP386-compatible version numbers. Thanks Jannis for the guidance.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17357 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/__init__.py

@@ -1,30 +1,30 @@
 VERSION = (1, 4, 0, 'alpha', 1)
 
-def get_version():
-    version = '%s.%s' % (VERSION[0], VERSION[1])
-    if VERSION[2]:
-        version = '%s.%s' % (version, VERSION[2])
-    if VERSION[3:] == ('alpha', 0):
-        version = '%s pre-alpha' % version
-    else:
-        if VERSION[3] != 'final':
-            version = '%s %s %s' % (version, VERSION[3], VERSION[4])
-    from django.utils.version import get_svn_revision
-    svn_rev = get_svn_revision()
-    if svn_rev != u'SVN-unknown':
-        version = "%s %s" % (version, svn_rev)
-    return version
+def get_version(version=None):
+    """Derives a PEP386-compliant version number from VERSION."""
+    if version is None:
+        version = VERSION
+    assert len(version) == 5
+    assert version[3] in ('alpha', 'beta', 'rc', 'final')
 
-def get_distutils_version():
-    # Distutils expects a version number formatted as major.minor[.patch][sub]
-    parts = 5
-    if VERSION[3] == 'final':
-        parts = 3
-        if VERSION[2] == 0:
-            parts = 2
-    version = VERSION[:parts]
-    version = [str(x)[0] for x in version]      # ['1', '4', '0', 'a', '1']
-    if parts > 2:
-        version[2:] = [''.join(version[2:])]    # ['1', '4', '0a1']
-    version = '.'.join(version)                 # '1.4.0a1'
-    return version
+    # Now build the two parts of the version number:
+    # main = X.Y[.Z]
+    # sub = .devN - for pre-alpha releases
+    #     | {a|b|c}N - for alpha, beta and rc releases
+
+    parts = 2 if version[2] == 0 else 3
+    main = '.'.join(str(x) for x in version[:parts])
+
+    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
+
+    elif version[3] != 'final':
+        mapping = {'alpha': 'a', 'beta': 'b', 'rc': 'c'}
+        sub = mapping[version[3]] + str(version[4])
+
+    return main + sub