♻️(backend) remove different reach for authenticated and anonymous

If anonymous users have reader access on a parent, we were considering
that an edge use case was interesting: allowing an authenticated user
to still be editor on the child.

Although this use case could be interesting, we consider, as a first
approach, that the value it carries is not big enough to justify the
complexity for the user to understand this complex access right heritage.

src/backend/core/models.py

@@ -115,16 +115,16 @@ class LinkReachChoices(models.TextChoices):
         if LinkRoleChoices.EDITOR in reach_roles.get(cls.PUBLIC, set()):
             return {cls.PUBLIC: [LinkRoleChoices.EDITOR]}
 
-        # Rule 2: public/reader
-        if LinkRoleChoices.READER in reach_roles.get(cls.PUBLIC, set()):
-            result.get(cls.AUTHENTICATED, set()).discard(LinkRoleChoices.READER)
-            result.pop(cls.RESTRICTED, None)
-
-        # Rule 3: authenticated/editor
+        # Rule 2: authenticated/editor
         if LinkRoleChoices.EDITOR in reach_roles.get(cls.AUTHENTICATED, set()):
             result[cls.AUTHENTICATED].discard(LinkRoleChoices.READER)
             result.pop(cls.RESTRICTED, None)
 
+        # Rule 3: public/reader
+        if LinkRoleChoices.READER in reach_roles.get(cls.PUBLIC, set()):
+            result.pop(cls.AUTHENTICATED, None)
+            result.pop(cls.RESTRICTED, None)
+
         # Rule 4: authenticated/reader
         if LinkRoleChoices.READER in reach_roles.get(cls.AUTHENTICATED, set()):
             result.pop(cls.RESTRICTED, None)

src/backend/core/tests/test_models_documents.py

@@ -1190,7 +1190,6 @@ def test_models_documents_restore_complex_bis(django_assert_num_queries):
         (
             [{"link_reach": "public", "link_role": "reader"}],
             {
-                "authenticated": ["editor"],
                 "public": ["reader", "editor"],
             },
         ),
@@ -1255,7 +1254,6 @@ def test_models_documents_restore_complex_bis(django_assert_num_queries):
                 {"link_reach": "public", "link_role": "reader"},
             ],
             {
-                "authenticated": ["editor"],
                 "public": ["reader", "editor"],
             },
         ),
@@ -1266,7 +1264,6 @@ def test_models_documents_restore_complex_bis(django_assert_num_queries):
                 {"link_reach": "public", "link_role": "reader"},
             ],
             {
-                "authenticated": ["editor"],
                 "public": ["reader", "editor"],
             },
         ),
@@ -1276,7 +1273,7 @@ def test_models_documents_restore_complex_bis(django_assert_num_queries):
                 {"link_reach": "authenticated", "link_role": "editor"},
                 {"link_reach": "public", "link_role": "reader"},
             ],
-            {"authenticated": ["editor"], "public": ["reader", "editor"]},
+            {"public": ["reader", "editor"]},
         ),
         (
             [