From 519165c0c5d26d4c9d1cb205012e29dc7472c529 Mon Sep 17 00:00:00 2001
From: Patrick Uiterwijk <patrick@puiterwijk.org>
Date: Oct 07 2018 11:32:55 +0000
Subject: Do not mark generate_acls and remove_acls as abstract methods


They are only required in non-dynamic ACL implementations.

Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>

---

diff --git a/pagure/lib/git_auth.py b/pagure/lib/git_auth.py
index b2532e9..1a40d41 100644
--- a/pagure/lib/git_auth.py
+++ b/pagure/lib/git_auth.py
@@ -9,7 +9,6 @@
 """
 from __future__ import print_function, unicode_literals
 
-import abc
 import json
 import logging
 import os
@@ -19,7 +18,6 @@ import tempfile
 from io import open
 
 import werkzeug
-from six import with_metaclass
 from six.moves import dbm_gnu
 
 import pagure.exceptions
@@ -80,16 +78,41 @@ def get_git_auth_helper(backend=None):
     return GIT_AUTH_BACKEND_INSTANCE
 
 
-class GitAuthHelper(with_metaclass(abc.ABCMeta, object)):
+class GitAuthHelper(object):
     """ The class to inherit from when creating your own git authentication
     helper.
     """
 
     is_dynamic = False
 
+    def __init__(self):
+        """ This method verifies that the correct functions are implemented.
+
+        When a subclass gets initiated, we verify that the correct functions
+        are implemented for it (generate/remote_acls for non-dynamic, check_acl
+        for dynamic subclassess), and raise a NotImplementedError otherwise.
+        """
+        if self.is_dynamic:
+            if self.check_acl == GitAuthHelper.check_acl:
+                raise NotImplementedError(
+                    "Dynamic Git auth backend %s does not implement check_acl"
+                    % self.__class__.__name__
+                )
+        else:
+            if self.generate_acls == GitAuthHelper.generate_acls:
+                raise NotImplementedError(
+                    "Static Git auth backend %s does not implement "
+                    "generate_acls"
+                    % self.__class__.__name__
+                )
+            if self.remove_acls == GitAuthHelper.remove_acls:
+                raise NotImplementedError(
+                    "Static Git auth backend %s does not implement remove_acls"
+                    % self.__class__.__name__
+                )
+
     @classmethod
-    @abc.abstractmethod
-    def generate_acls(self, project, group=None):
+    def generate_acls(cls, project, group=None):
         """ This is the method that is called by pagure to generate the
         configuration file.
 
@@ -111,11 +134,13 @@ class GitAuthHelper(with_metaclass(abc.ABCMeta, object)):
         feel free to let us know.)
 
         """
-        pass
+        if not cls.is_dynamic:
+            raise NotImplementedError(
+                "Non-dynamic ACL plugins must implement generate_acls"
+            )
 
     @classmethod
-    @abc.abstractmethod
-    def remove_acls(self, session, project):
+    def remove_acls(cls, session, project):
         """ This is the method that is called by pagure to remove a project
         from the configuration file.
 
@@ -127,11 +152,12 @@ class GitAuthHelper(with_metaclass(abc.ABCMeta, object)):
         :type project: pagure.lib.model.Project
 
         """
-        pass
+        if not cls.is_dynamic:
+            raise NotImplementedError(
+                "Non-dynamic ACL plugins must implement remove_acls"
+            )
 
     @classmethod
-    # This method can't be marked as abstract, since it's new and that would
-    # break backwards compatibility
     def check_acl(cls, session, project, username, refname, **info):
         """ This method is used in Dynamic Git Auth helpers to check acls.
 
@@ -171,9 +197,10 @@ class GitAuthHelper(with_metaclass(abc.ABCMeta, object)):
                 single ref from being updated, only return False if is_update
                 is True.
         """
-        raise NotImplementedError(
-            "check_acl on static Git Auth Backend called"
-        )
+        if cls.is_dynamic:
+            raise NotImplementedError(
+                "check_acl on static Git Auth Backend called"
+            )
 
 
 def _read_file(filename):