test_create_table_error_rows_twice_with_duplicates, refs #1927

datasette/views/database.py

@@ -683,7 +683,11 @@ async def post(self, request):
             bad_pks = False
             if len(actual_pks) == 1 and data.get("pk") and data["pk"] != actual_pks[0]:
                 bad_pks = True
-            elif len(actual_pks) > 1 and data.get("pks") and set(data["pks"]) != set(actual_pks):
+            elif (
+                len(actual_pks) > 1
+                and data.get("pks")
+                and set(data["pks"]) != set(actual_pks)
+            ):
                 bad_pks = True
             if bad_pks:
                 return _error(["pk cannot be changed for existing table"])

tests/test_api_write.py

@@ -1236,6 +1236,39 @@ async def test_create_table_error_if_pk_changed(ds_write):
     }
 
 
+@pytest.mark.asyncio
+async def test_create_table_error_rows_twice_with_duplicates(ds_write):
+    # Error if you don't send ignore: True or replace: True
+    token = write_token(ds_write)
+    input = {
+        "rows": [{"id": 1, "name": "Row 1"}, {"id": 2, "name": "Row 2"}],
+        "table": "test_create_twice",
+        "pk": "id",
+    }
+    first_response = await ds_write.client.post(
+        "/data/-/create",
+        json=input,
+        headers={
+            "Authorization": "Bearer {}".format(token),
+            "Content-Type": "application/json",
+        },
+    )
+    assert first_response.status_code == 201
+    second_response = await ds_write.client.post(
+        "/data/-/create",
+        json=input,
+        headers={
+            "Authorization": "Bearer {}".format(token),
+            "Content-Type": "application/json",
+        },
+    )
+    assert second_response.status_code == 400
+    assert second_response.json() == {
+        "ok": False,
+        "errors": ["UNIQUE constraint failed: test_create_twice.id"],
+    }
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "path",