remove _json_from_json patch

.changes/unreleased/Fixes-20231219-153446.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: remove json patch to leverage bigquery-python improvement
+time: 2023-12-19T15:34:46.843931-08:00
+custom:
+  Author: colin-rogers-dbt
+  Issue: "1055"

dbt/adapters/bigquery/connections.py

@@ -15,7 +15,6 @@
 
 import google.auth
 import google.auth.exceptions
-import google.cloud.bigquery as bigquery
 import google.cloud.exceptions
 from google.api_core import retry, client_info
 from google.auth import impersonated_credentials
@@ -63,16 +62,6 @@
 )
 
 
-# Override broken json deserializer for dbt show --inline
-# can remove once this is fixed: https://github.com/googleapis/python-bigquery/issues/1500
-def _json_from_json(value, _):
-    """NOOP string -> string coercion"""
-    return json.loads(value)
-
-
-bigquery._helpers._CELLDATA_FROM_JSON["JSON"] = _json_from_json
-
-
 @lru_cache()
 def get_bigquery_defaults(scopes=None) -> Tuple[Any, Optional[str]]:
     """

dev-requirements.txt

@@ -2,7 +2,7 @@
 # TODO: how to automate switching from develop to version branches?
 git+https://github.com/dbt-labs/dbt-core.git#egg=dbt-core&subdirectory=core
 git+https://github.com/dbt-labs/dbt-core.git#egg=dbt-tests-adapter&subdirectory=tests/adapter
-
+git+https://github.com/googleapis/python-bigquery.git#egg=google-cloud-bigquery
 # if version 1.x or greater -> pin to major version
 # if version 0.x -> pin to minor
 black~=23.12

tests/functional/adapter/dbt_show/test_dbt_show.py

@@ -24,6 +24,10 @@
     limit 5
     """
 
+model_with_null_json_struct = """
+    select (struct<k json>(null)) as null_struct
+"""
+
 
 class TestBigQueryShowLimit(BaseShowLimit):
     pass
@@ -40,7 +44,11 @@ class TestBigQueryShowSqlWorksWithJSONStruct:
     def models(self):
         return {
             "json_struct_model.sql": model_with_json_struct,
+            "null_json_struct_model.sql": model_with_null_json_struct,
         }
 
     def test_sql_header(self, project):
         run_dbt(["show", "--select", "json_struct_model"])
+
+    def test_show_with_null_json_struct(self, project):
+        run_dbt(["show", "--select", "null_json_struct_model"])