fix(bigquery): maintain custom client project id when provided

Author: dlstadther

ibis/backends/bigquery/__init__.py

@@ -410,7 +410,8 @@ def do_connect(
             An instance of the BigQuery backend.
 
         """
-        default_project_id = client.project if client is not None else project_id
+        client_project_id = client.project if client is not None else None
+        default_project_id = None
 
         # Only need `credentials` to create a `client` and
         # `storage_client`, so only one or the other needs to be set.
@@ -443,7 +444,7 @@ def do_connect(
                 use_local_webserver=auth_local_webserver,
             )
 
-        project_id = project_id or default_project_id
+        project_id = client_project_id or project_id or default_project_id
 
         (
             self.data_project,

ibis/backends/bigquery/tests/system/test_connect.py

@@ -256,3 +256,21 @@ def test_create_table_from_memtable_needs_quotes(project_id, dataset_id, credent
         assert t.schema() == ibis.schema(schema)
     finally:
         con.drop_table(name)
+
+
+def test_project_id_from_arg(project_id):
+    con = ibis.bigquery.connect(project_id=project_id)
+    assert con.project_id == project_id
+
+
+def test_project_id_from_client(project_id):
+    bq_client = bq.Client(project=project_id)
+    con = ibis.bigquery.connect(client=bq_client, project_id="not-a-real-project")
+    assert con.project_id == project_id
+
+
+def test_project_id_from_default(default_credentials):
+    _, default_project_id = default_credentials
+    # `connect()` re-evaluates default credentials and sets project_id since no client nor explicit project_id is provided
+    con = ibis.bigquery.connect()
+    assert con.project_id == default_project_id