Un-deprecate index methods from Elasticsearch2SearchBackend

As discussed at https://github.com/wagtail/wagtail/pull/3975#issuecomment-389961302 - the base search backend class now implements generic versions of these methods so that they can be removed from the ES2-specific code without any loss of functionality.

wagtail/search/backends/base.py

@@ -4,7 +4,7 @@ from django.db.models.lookups import Lookup
 from django.db.models.query import QuerySet
 from django.db.models.sql.where import SubqueryConstraint, WhereNode
 
-from wagtail.search.index import class_is_indexed
+from wagtail.search.index import class_is_indexed, get_indexed_models
 from wagtail.search.query import MATCH_ALL, PlainText
 
 
@@ -272,6 +272,28 @@ class EmptySearchResults(BaseSearchResults):
         return 0
 
 
+class NullIndex:
+    """
+    Index class that provides do-nothing implementations of the indexing operations required by
+    BaseSearchBackend. Use this for search backends that do not maintain an index, such as the
+    database backend.
+    """
+    def add_model(self, model):
+        pass
+
+    def refresh(self):
+        pass
+
+    def add_item(self, item):
+        pass
+
+    def add_items(self, model, items):
+        pass
+
+    def delete_item(self, item):
+        pass
+
+
 class BaseSearchBackend:
     query_compiler_class = None
     autocomplete_query_compiler_class = None
@@ -282,7 +304,7 @@ class BaseSearchBackend:
         pass
 
     def get_index_for_model(self, model):
-        return None
+        return NullIndex()
 
     def get_rebuilder(self):
         return None
@@ -291,19 +313,24 @@ class BaseSearchBackend:
         raise NotImplementedError
 
     def add_type(self, model):
-        raise NotImplementedError
+        self.get_index_for_model(model).add_model(model)
 
     def refresh_index(self):
-        raise NotImplementedError
+        refreshed_indexes = []
+        for model in get_indexed_models:
+            index = self.get_index_for_model(model)
+            if index not in refreshed_indexes:
+                index.refresh()
+                refreshed_indexes.append(index)
 
     def add(self, obj):
-        raise NotImplementedError
+        self.get_index_for_model(type(obj)).add_item(obj)
 
     def add_bulk(self, model, obj_list):
-        raise NotImplementedError
+        self.get_index_for_model(model).add_items(model, obj_list)
 
     def delete(self, obj):
-        raise NotImplementedError
+        self.get_index_for_model(type(obj)).delete_item(obj)
 
     def _search(self, query_compiler_class, query, model_or_queryset, **kwargs):
         # Find model/queryset

wagtail/search/backends/elasticsearch2.py

@@ -1,6 +1,5 @@
 import copy
 import json
-import warnings
 from collections import OrderedDict
 from urllib.parse import urlparse
 
@@ -16,7 +15,6 @@ from wagtail.search.backends.base import (
 from wagtail.search.index import (
     AutocompleteField, FilterField, Indexed, RelatedFields, SearchField, class_is_indexed)
 from wagtail.search.query import And, Boost, MatchAll, Not, Or, PlainText
-from wagtail.utils.deprecation import RemovedInWagtail22Warning
 from wagtail.utils.utils import deep_update
 
 
@@ -1100,50 +1098,5 @@ class Elasticsearch2SearchBackend(BaseSearchBackend):
         # Use the rebuilder to reset the index
         self.get_rebuilder().reset_index()
 
-    def add_type(self, model):
-        warnings.warn(
-            "The `backend.add_type(model)` method is deprecated. "
-            "Please use `backend.get_index_for_model(model).add_model(model)` instead.",
-            category=RemovedInWagtail22Warning
-        )
-
-        self.get_index_for_model(model).add_model(model)
-
-    def refresh_index(self):
-        warnings.warn(
-            "The `backend.refresh_index()` method is deprecated. "
-            "Please use `backend.get_index_for_model(model).refresh()` for each model instead.",
-            category=RemovedInWagtail22Warning
-        )
-
-        self.get_index().refresh()
-
-    def add(self, obj):
-        warnings.warn(
-            "The `backend.add(obj)` method is deprecated. "
-            "Please use `backend.get_index_for_model(type(obj)).add_item(obj)` instead.",
-            category=RemovedInWagtail22Warning
-        )
-
-        self.get_index_for_model(type(obj)).add_item(obj)
-
-    def add_bulk(self, model, obj_list):
-        warnings.warn(
-            "The `backend.add_bulk(model, obj_list)` method is deprecated. "
-            "Please use `self.get_index_for_model(model).add_items(model, obj_list)` instead.",
-            category=RemovedInWagtail22Warning
-        )
-
-        self.get_index_for_model(model).add_items(model, obj_list)
-
-    def delete(self, obj):
-        warnings.warn(
-            "The `backend.delete(obj)` method is deprecated. "
-            "Please use `backend.get_index_for_model(type(obj)).delete_item(obj)` instead.",
-            category=RemovedInWagtail22Warning
-        )
-
-        self.get_index_for_model(type(obj)).delete_item(obj)
-
 
 SearchBackend = Elasticsearch2SearchBackend

wagtail/search/tests/test_db_backend.py

@@ -33,11 +33,6 @@ class TestDBBackend(BackendTests, TestCase):
     def test_search_boosting_on_related_fields(self):
         super().test_search_boosting_on_related_fields()
 
-    # Doesn't support ranking
-    @unittest.expectedFailure
-    def test_same_rank_pages(self):
-        super(TestDBBackend, self).test_same_rank_pages()
-
     # Doesn't support searching specific fields
     @unittest.expectedFailure
     def test_search_child_class_field_from_parent(self):

wagtail/utils/deprecation.py

@@ -1,7 +1,3 @@
-class RemovedInWagtail22Warning(DeprecationWarning):
-    pass
-
-
 class RemovedInWagtail23Warning(DeprecationWarning):
     pass