Fixed #28126 -- Added GistIndex to contrib.postgres.

Thanks to Marc Tamlyn for the initial patch.

django/contrib/postgres/indexes.py

@@ -1,16 +1,19 @@
 from django.db.models import Index
 
-__all__ = ['BrinIndex', 'GinIndex']
+__all__ = ['BrinIndex', 'GinIndex', 'GistIndex']
 
 
-class BrinIndex(Index):
-    suffix = 'brin'
+class MaxLengthMixin:
     # Allow an index name longer than 30 characters since the suffix is 4
     # characters (usual limit is 3). Since this index can only be used on
     # PostgreSQL, the 30 character limit for cross-database compatibility isn't
     # applicable.
     max_name_length = 31
 
+
+class BrinIndex(MaxLengthMixin, Index):
+    suffix = 'brin'
+
     def __init__(self, *, pages_per_range=None, **kwargs):
         if pages_per_range is not None and pages_per_range <= 0:
             raise ValueError('pages_per_range must be None or a positive integer')
@@ -58,3 +61,31 @@ class GinIndex(Index):
         if with_params:
             statement.parts['extra'] = 'WITH ({}) {}'.format(', '.join(with_params), statement.parts['extra'])
         return statement
+
+
+class GistIndex(MaxLengthMixin, Index):
+    suffix = 'gist'
+
+    def __init__(self, *, buffering=None, fillfactor=None, **kwargs):
+        self.buffering = buffering
+        self.fillfactor = fillfactor
+        super().__init__(**kwargs)
+
+    def deconstruct(self):
+        path, args, kwargs = super().deconstruct()
+        if self.buffering is not None:
+            kwargs['buffering'] = self.buffering
+        if self.fillfactor is not None:
+            kwargs['fillfactor'] = self.fillfactor
+        return path, args, kwargs
+
+    def create_sql(self, model, schema_editor):
+        statement = super().create_sql(model, schema_editor, using=' USING gist')
+        with_params = []
+        if self.buffering is not None:
+            with_params.append('buffering = {}'.format('on' if self.buffering else 'off'))
+        if self.fillfactor is not None:
+            with_params.append('fillfactor = %s' % self.fillfactor)
+        if with_params:
+            statement.parts['extra'] = 'WITH ({}) {}'.format(', '.join(with_params), statement.parts['extra'])
+        return statement

django/contrib/postgres/operations.py

@@ -33,6 +33,12 @@ class BtreeGinExtension(CreateExtension):
         self.name = 'btree_gin'
 
 
+class BtreeGistExtension(CreateExtension):
+
+    def __init__(self):
+        self.name = 'btree_gist'
+
+
 class CITextExtension(CreateExtension):
 
     def __init__(self):