Fix case of empty results

POSTHOG-TTG

posthog/tasks/exports/csv_exporter.py

@@ -100,10 +100,12 @@ def _convert_response_to_csv_data(data: Any) -> Generator[Any, None, None]:
             return
 
     if isinstance(results, list):
-        first_result = results[0]
+        first_result = next(iter(results), None)
 
-        # persons modal like
-        if len(results) == 1 and set(results[0].keys()) == {"people", "count"}:
+        if not first_result:
+            return
+        elif len(results) == 1 and set(results[0].keys()) == {"people", "count"}:
+            # persons modal like
             yield from results[0].get("people")
             return
         elif isinstance(first_result, list) or first_result.get("action_id"):

posthog/tasks/exports/test/csv_renders/hogql_empty.json

@@ -0,0 +1,7 @@
+{
+    "csv_rows": ["person,id,created_at,person.$delete", ",,,", ""],
+    "response": {
+        "columns": ["person", "id", "created_at", "person.$delete"],
+        "results": []
+    }
+}

posthog/tasks/exports/test/test_csv_exporter_renders.py

@@ -59,7 +59,7 @@ def test_csv_rendering(mock_settings, mock_process_query, mock_request, filename
         if fixture.get("hogql_response"):
             # If HogQL has a different response structure, add it to the fixture as `hogql_response`
             mock_process_query.return_value = fixture["hogql_response"]
-        elif fixture["response"].get("results"):
+        elif fixture["response"].get("results") is not None:
             mock_process_query.return_value = fixture["response"]
         else:
             mock_process_query.return_value = {"results": fixture["response"].pop("result"), **fixture["response"]}