fix(sql): quote identifiers in transpile_to_dialect to fix case-sensitive column filters (#39521)

superset/common/query_object.py

@@ -360,11 +360,18 @@ class QueryObject:  # pylint: disable=too-many-instance-attributes
                     engine = database.db_engine_spec.engine
 
                     if needs_transpilation:
-                        clause = transpile_to_dialect(clause, engine)
+                        # source_engine=engine ensures idempotency: this
+                        # method can run more than once (validate() is called
+                        # from both raise_for_access and get_df_payload), so
+                        # the second pass must be able to re-parse the
+                        # dialect-specific output (e.g. BigQuery backticks)
+                        # produced by the first pass.
+                        clause = transpile_to_dialect(
+                            clause, engine, source_engine=engine, identify=True
+                        )
 
                     sanitized_clause = sanitize_clause(clause, engine)
-                    if sanitized_clause != clause:
-                        self.extras[param] = sanitized_clause
+                    self.extras[param] = sanitized_clause
                 except QueryClauseValidationException as ex:
                     raise QueryObjectValidationError(ex.message) from ex
 

superset/sql/parse.py

@@ -1568,6 +1568,7 @@ def transpile_to_dialect(
     sql: str,
     target_engine: str,
     source_engine: str | None = None,
+    identify: bool = False,
 ) -> str:
     """
     Transpile SQL from one database dialect to another using SQLGlot.
@@ -1576,6 +1577,7 @@ def transpile_to_dialect(
         sql: The SQL query to transpile
         target_engine: The target database engine (e.g., "mysql", "postgresql")
         source_engine: The source database engine. If None, uses generic SQL dialect.
+        identify: If True, quote all identifiers per the target dialect.
 
     Returns:
         The transpiled SQL string
@@ -1598,6 +1600,7 @@ def transpile_to_dialect(
             copy=True,
             comments=False,
             pretty=False,
+            identify=identify,
         )
     except ParseError as ex:
         raise QueryClauseValidationException(f"Cannot parse SQL clause: {sql}") from ex

tests/unit_tests/sql/transpile_to_dialect_test.py

@@ -396,3 +396,127 @@ def test_transpile_unknown_source_engine_uses_generic() -> None:
         "SELECT * FROM orders", "postgresql", "unknown_engine"
     )
     assert result == "SELECT * FROM orders"
+
+
+# Tests for identify=True (identifier quoting)
+@pytest.mark.parametrize(
+    "sql,dialect,expected",
+    [
+        # PostgreSQL - double-quoted identifiers
+        (
+            "STATE ILIKE '%AL%'",
+            "postgresql",
+            "\"STATE\" ILIKE '%AL%'",
+        ),
+        # MySQL - backtick-quoted identifiers, ILIKE transpiled
+        (
+            "STATE ILIKE '%AL%'",
+            "mysql",
+            "LOWER(`STATE`) LIKE LOWER('%AL%')",
+        ),
+        # BigQuery - backtick-quoted identifiers, ILIKE transpiled
+        (
+            "STATE ILIKE '%AL%'",
+            "bigquery",
+            "LOWER(`STATE`) LIKE LOWER('%AL%')",
+        ),
+        # Snowflake - double-quoted identifiers
+        (
+            "STATE ILIKE '%AL%'",
+            "snowflake",
+            "\"STATE\" ILIKE '%AL%'",
+        ),
+        # MSSQL - bracket-quoted identifiers
+        (
+            "STATE = 'CA'",
+            "mssql",
+            "[STATE] = 'CA'",
+        ),
+        # Compound filter with multiple identifiers
+        (
+            "STATE = 'CA' AND AIRLINE = 'Delta'",
+            "postgresql",
+            "\"STATE\" = 'CA' AND \"AIRLINE\" = 'Delta'",
+        ),
+        # Lowercase identifiers also get quoted
+        (
+            "name = 'test'",
+            "postgresql",
+            "\"name\" = 'test'",
+        ),
+    ],
+)
+def test_identify_quotes_identifiers(sql: str, dialect: str, expected: str) -> None:
+    """Test that identify=True quotes identifiers per target dialect."""
+    assert transpile_to_dialect(sql, dialect, identify=True) == expected
+
+
+def test_identify_unknown_engine_returns_unchanged() -> None:
+    """Test that identify=True has no effect on unknown engines."""
+    sql = "STATE = 'CA'"
+    assert transpile_to_dialect(sql, "unknown_engine", identify=True) == sql
+
+
+@pytest.mark.parametrize(
+    "sql,engine,expected",
+    [
+        (
+            "STATE ILIKE '%AL%'",
+            "postgresql",
+            "\"STATE\" ILIKE '%AL%'",
+        ),
+        (
+            "country ILIKE '%Italy%'",
+            "bigquery",
+            "LOWER(`country`) LIKE LOWER('%Italy%')",
+        ),
+    ],
+)
+def test_identify_with_source_engine(sql: str, engine: str, expected: str) -> None:
+    """Test identify=True with source_engine matching target engine."""
+    result = transpile_to_dialect(sql, engine, source_engine=engine, identify=True)
+    assert result == expected
+
+
+@pytest.mark.parametrize(
+    "engine",
+    ["postgresql", "bigquery", "mysql", "snowflake"],
+)
+def test_identify_transpilation_is_idempotent(engine: str) -> None:
+    """Test that transpiling twice produces the same result (idempotent).
+
+    This matters because _sanitize_filters() can be called multiple times
+    via validate().
+    """
+    clause = "STATE ILIKE '%AL%'"
+    pass1 = transpile_to_dialect(clause, engine, source_engine=engine, identify=True)
+    pass2 = transpile_to_dialect(pass1, engine, source_engine=engine, identify=True)
+    assert pass1 == pass2
+
+
+def test_sanitize_filters_writes_back_transpiled_clause() -> None:
+    """Test that _sanitize_filters always persists the transpiled clause.
+
+    Regression test: a previous conditional `if sanitized_clause != clause`
+    skipped the write-back when transpile_to_dialect had already modified
+    the clause, leaving the original unquoted value in extras.
+    """
+    from unittest.mock import MagicMock
+
+    from superset.common.query_object import QueryObject
+
+    mock_datasource = MagicMock()
+    mock_datasource.database.db_engine_spec.engine = "postgresql"
+
+    query_obj = QueryObject(
+        datasource=mock_datasource,
+        columns=["STATE"],
+        metrics=[],
+        extras={
+            "where": "STATE = 'CA'",
+            "transpile_to_dialect": True,
+        },
+    )
+    query_obj.validate()
+
+    assert '"STATE"' in query_obj.extras["where"]