fix(postgres): handle enums by delegating to the parent class (#9769)

Handle postgres enum types as unknown. Closes #9295.

Author: cpcloud

ibis/backends/postgres/tests/test_client.py

@@ -384,7 +384,7 @@ def test_infoschema_dtypes(con):
 
 
 def test_password_with_bracket():
-    password = f"{IBIS_POSTGRES_PASS}["
+    password = f"{IBIS_POSTGRES_PASS}[]"
     quoted_pass = quote_plus(password)
     url = f"postgres://{IBIS_POSTGRES_USER}:{quoted_pass}@{IBIS_POSTGRES_HOST}:{IBIS_POSTGRES_PORT}/{POSTGRES_TEST_DB}"
     with pytest.raises(
@@ -417,3 +417,18 @@ def test_create_geospatial_table_with_srid(con):
             for column, dtype in zip(column_names, column_types)
         }
     )
+
+
+@pytest.fixture(scope="module")
+def enum_table(con):
+    name = gen_name("enum_table")
+    con.raw_sql("CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy')")
+    con.raw_sql(f"CREATE TEMP TABLE {name} (mood mood)")
+    yield name
+    con.raw_sql(f"DROP TABLE {name}")
+    con.raw_sql("DROP TYPE mood")
+
+
+def test_enum_table(con, enum_table):
+    t = con.table(enum_table)
+    assert t.mood.type() == dt.unknown

ibis/backends/sql/datatypes.py

@@ -193,12 +193,11 @@ def from_string(cls, text: str, nullable: bool | None = None) -> dt.DataType:
 
         try:
             sgtype = sg.parse_one(text, into=sge.DataType, read=cls.dialect)
-            return cls.to_ibis(sgtype, nullable=nullable)
         except sg.errors.ParseError:
             # If sqlglot can't parse the type fall back to `dt.unknown`
-            pass
-
-        return dt.unknown
+            return dt.unknown
+        else:
+            return cls.to_ibis(sgtype, nullable=nullable)
 
     @classmethod
     def to_string(cls, dtype: dt.DataType) -> str:
@@ -468,11 +467,8 @@ def _from_ibis_Map(cls, dtype: dt.Map) -> sge.DataType:
     def from_string(cls, text: str, nullable: bool | None = None) -> dt.DataType:
         if text.lower().startswith("vector"):
             text = "vector"
-        if dtype := cls.unknown_type_strings.get(text.lower()):
-            return dtype
 
-        sgtype = sg.parse_one(text, into=sge.DataType, read=cls.dialect)
-        return cls.to_ibis(sgtype, nullable=nullable)
+        return super().from_string(text, nullable=nullable)
 
 
 class RisingWaveType(PostgresType):