Copy get_version implementation from Wagtail

wagtail_localize/__init__.py

@@ -1,4 +1,4 @@
-from wagtail.utils.version import get_version
+from .version import get_version
 
 
 default_app_config = 'wagtail_localize.apps.WagtailLocalizeAppConfig'

wagtail_localize/version.py

@@ -0,0 +1,42 @@
+
+# This file is heavily inspired by django.utils.version
+
+
+def get_version(version):
+    """Return a PEP 440-compliant version number from VERSION."""
+    version = get_complete_version(version)
+
+    # Now build the two parts of the version number:
+    # main = X.Y[.Z]
+    # sub = .devN - for pre-alpha releases
+    #     | {a|b|rc}N - for alpha, beta, and rc releases
+
+    main = get_main_version(version)
+
+    sub = ''
+    if version[3] != 'final':
+        mapping = {'alpha': 'a', 'beta': 'b', 'rc': 'rc', 'dev': '.dev'}
+        sub = mapping[version[3]] + str(version[4])
+
+    return main + sub
+
+
+def get_main_version(version=None):
+    """Return main version (X.Y[.Z]) from VERSION."""
+    version = get_complete_version(version)
+    parts = 2 if version[2] == 0 else 3
+    return '.'.join(str(x) for x in version[:parts])
+
+
+def get_complete_version(version=None):
+    """
+    Return a tuple of the Wagtail version. If version argument is non-empty,
+    check for correctness of the tuple provided.
+    """
+    if version is None:
+        from wagtail import VERSION as version
+    else:
+        assert len(version) == 5
+        assert version[3] in ('dev', 'alpha', 'beta', 'rc', 'final')
+
+    return version