fix(sqlalchemy-spanner): fail fast on non-string names and fix AND spacing

Author: Samin061

packages/sqlalchemy-spanner/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py

@@ -86,6 +86,11 @@ def _escape_sql_string_literal(value):
     otherwise close the literal so the remainder is parsed as SQL. Escaping the
     backslash, both quote characters and newlines keeps the name contained.
     """
+    if not isinstance(value, str):
+        raise spanner_dbapi.exceptions.ProgrammingError(
+            "Unsupported type for SQL string literal escaping: "
+            "{!r}".format(type(value).__name__)
+        )
     return (
         value.replace("\\", "\\\\")
         .replace("'", "\\'")
@@ -1549,7 +1554,7 @@ def get_multi_foreign_keys(
                 The schema is ``None`` if no schema is provided.
         """
         table_filter_query = self._get_table_filter_query(filter_names, "tc", True)
-        schema_filter_query = " tc.table_schema = '{schema}' AND".format(
+        schema_filter_query = " tc.table_schema = '{schema}' AND ".format(
             schema=_escape_sql_string_literal(schema or "")
         )
         table_type_query = self._get_table_type_query(kind, True)

packages/sqlalchemy-spanner/tests/unit/test_dialect.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 from unittest.mock import MagicMock
+import pytest
 from sqlalchemy.testing import eq_
 from sqlalchemy.testing.plugin.plugin_base import fixtures
 from google.cloud.sqlalchemy_spanner.sqlalchemy_spanner import SpannerDialect
@@ -154,3 +155,16 @@ def test_escape_sql_string_literal(self):
         eq_(_escape_sql_string_literal("a\\b"), "a\\\\b")
         eq_(_escape_sql_string_literal("a\nb"), "a\\nb")
         eq_(_escape_sql_string_literal("plain"), "plain")
+
+    def test_escape_sql_string_literal_rejects_non_string(self):
+        """A non-string name must fail fast rather than be silently coerced."""
+        from google.cloud.sqlalchemy_spanner.sqlalchemy_spanner import (
+            _escape_sql_string_literal,
+        )
+        from google.cloud.spanner_dbapi.exceptions import ProgrammingError
+
+        with pytest.raises(ProgrammingError):
+            _escape_sql_string_literal(None)
+
+        with pytest.raises(ProgrammingError):
+            _escape_sql_string_literal(123)