Fix postgresql_include in create_index

Fixed issue where usage of the PostgreSQL ``postgresql_include`` option
within a :meth:`.Operations.create_index` would raise a KeyError, as the
additional column(s) need to be added to the table object used by the
construct internally. The issue is equivalent to the SQL Server issue fixed
in 🎫`513`. Pull request courtesy Steven Bronson.

Copied from e01041b and 174cb4b.

Fixes: #874
Closes: #875
Pull-request: #875
Pull-request-sha: 2f9b518

Change-Id: I68cc2a75dafd3297c5121c5125ff9c463c74f777

alembic/ddl/postgresql.py

@@ -16,6 +16,7 @@
 from sqlalchemy.dialects.postgresql import BIGINT
 from sqlalchemy.dialects.postgresql import ExcludeConstraint
 from sqlalchemy.dialects.postgresql import INTEGER
+from sqlalchemy.schema import CreateIndex
 from sqlalchemy.sql.elements import ColumnClause
 from sqlalchemy.sql.elements import UnaryExpression
 from sqlalchemy.types import NULLTYPE
@@ -71,6 +72,16 @@ class PostgresqlImpl(DefaultImpl):
     )
     identity_attrs_ignore = ("on_null", "order")
 
+    def create_index(self, index):
+        # this likely defaults to None if not present, so get()
+        # should normally not return the default value.  being
+        # defensive in any case
+        postgresql_include = index.kwargs.get("postgresql_include", None) or ()
+        for col in postgresql_include:
+            if col not in index.table.c:
+                index.table.append_column(Column(col, sqltypes.NullType))
+        self._exec(CreateIndex(index))
+
     def prep_table_for_batch(self, batch_impl, table):
 
         for constraint in table.constraints:

docs/build/unreleased/874.rst

@@ -0,0 +1,9 @@
+.. change::
+   :tags: bug, postgresql
+   :tickets: 874
+
+   Fixed issue where usage of the PostgreSQL ``postgresql_include`` option
+   within a :meth:`.Operations.create_index` would raise a KeyError, as the
+   additional column(s) need to be added to the table object used by the
+   construct internally. The issue is equivalent to the SQL Server issue fixed
+   in :ticket:`513`. Pull request courtesy Steven Bronson.

tests/test_postgresql.py

@@ -103,6 +103,19 @@ def test_create_index_postgresql_concurrently(self):
             "CREATE INDEX CONCURRENTLY geocoded ON locations (coordinates)"
         )
 
+    @config.requirements.sqlalchemy_14
+    def test_create_index_postgresql_include(self):
+        context = op_fixture("postgresql")
+        op.create_index(
+            "i", "t", ["c1", "c2"], unique=False, postgresql_include=["inc"]
+        )
+        context.assert_("CREATE INDEX i ON t (c1, c2) INCLUDE (inc)")
+
+    def test_create_index_postgresql_include_is_none(self):
+        context = op_fixture("postgresql")
+        op.create_index("i", "t", ["c1", "c2"], unique=False)
+        context.assert_("CREATE INDEX i ON t (c1, c2)")
+
     def test_drop_index_postgresql_concurrently(self):
         context = op_fixture("postgresql")
         op.drop_index("geocoded", "locations", postgresql_concurrently=True)