fix the custom datatype

ibis-server/app/model/connector.py

@@ -5,7 +5,6 @@
 from typing import Any
 
 import ibis
-import ibis.backends.bigquery
 import ibis.expr.datatypes as dt
 import ibis.expr.schema as sch
 import ibis.formats
@@ -117,6 +116,9 @@ def query(self, sql: str, limit: int) -> pd.DataFrame:
         try:
             return super().query(sql, limit)
         except ValueError as e:
+            # Import here to avoid override the custom datatypes
+            import ibis.backends.bigquery
+
             # Try to match the error message from the google cloud bigquery library matching Arrow type error.
             # If the error message matches, requries to get the schema from the result and generate a empty pandas dataframe with the mapped schema
             #

ibis-server/tests/routers/v2/connector/test_bigquery.py

@@ -199,7 +199,7 @@ async def test_query_values(client, manifest_str):
 
 
 async def test_query_empty_json(client, manifest_str):
-    # Test the empty result with json column
+    """Test the empty result with json column."""
     response = await client.post(
         url=f"{base_url}/query",
         json={
@@ -213,7 +213,7 @@ async def test_query_empty_json(client, manifest_str):
     assert len(result["data"]) == 0
     assert result["dtypes"] == {"f0_": "object"}
 
-    # Test only the json column is null
+    """Test only the json column is null."""
     response = await client.post(
         url=f"{base_url}/query",
         json={
@@ -260,6 +260,36 @@ async def test_avg_interval(client, manifest_str):
     assert result["dtypes"] == {"col": "object"}
 
 
+async def test_custom_datatypes_no_overrides(client, manifest_str):
+    # Trigger import the official BigQueryType
+    response = await client.post(
+        url=f"{base_url}/query",
+        json={
+            "manifestStr": manifest_str,
+            "connectionInfo": connection_info,
+            "sql": "select json_object('a', 1, 'b', 2) limit 0",
+        },
+    )
+    assert response.status_code == 200
+    result = response.json()
+    assert len(result["data"]) == 0
+    assert result["dtypes"] == {"f0_": "object"}
+
+    # Should use back the custom BigQueryType
+    response = await client.post(
+        url=f"{base_url}/query",
+        json={
+            "connectionInfo": connection_info,
+            "manifestStr": manifest_str,
+            "sql": "SELECT INTERVAL '1' YEAR + INTERVAL '100' MONTH + INTERVAL '100' DAY + INTERVAL '1' HOUR AS col",
+        },
+    )
+    assert response.status_code == 200
+    result = response.json()
+    assert result["data"][0] == ["112 months 100 days 3600000000 microseconds"]
+    assert result["dtypes"] == {"col": "object"}
+
+
 async def test_validate_with_unknown_rule(client, manifest_str):
     response = await client.post(
         url=f"{base_url}/validate/unknown_rule",