Backport of CSV labels fix from #2214

datasette/views/base.py

@@ -308,9 +308,11 @@ async def stream_fn(r):
                                     if cell is None:
                                         new_row.extend(("", ""))
                                     else:
-                                        assert isinstance(cell, dict)
-                                        new_row.append(cell["value"])
-                                        new_row.append(cell["label"])
+                                        if not isinstance(cell, dict):
+                                            new_row.extend((cell, ""))
+                                        else:
+                                            new_row.append(cell["value"])
+                                            new_row.append(cell["label"])
                                 else:
                                     new_row.append(cell)
                             await writer.writerow(new_row)

tests/test_csv.py

@@ -1,10 +1,12 @@
+from datasette.app import Datasette
 from bs4 import BeautifulSoup as Soup
 from .fixtures import (  # noqa
     app_client,
     app_client_csv_max_mb_one,
     app_client_with_cors,
     app_client_with_trace,
 )
+import pytest
 import urllib.parse
 
 EXPECTED_TABLE_CSV = """id,content
@@ -90,6 +92,40 @@ def test_table_csv_with_nullable_labels(app_client):
     assert response.text == EXPECTED_TABLE_WITH_NULLABLE_LABELS_CSV
 
 
+@pytest.mark.asyncio
+async def test_table_csv_with_invalid_labels():
+    # https://github.com/simonw/datasette/issues/2214
+    ds = Datasette()
+    await ds.invoke_startup()
+    db = ds.add_memory_database("db_2214")
+    await db.execute_write_script(
+        """
+        create table t1 (id integer primary key, name text);
+        insert into t1 (id, name) values (1, 'one');
+        insert into t1 (id, name) values (2, 'two');
+        create table t2 (textid text primary key, name text);
+        insert into t2 (textid, name) values ('a', 'alpha');
+        insert into t2 (textid, name) values ('b', 'beta');
+        create table if not exists maintable (
+            id integer primary key,
+            fk_integer integer references t1(id),
+            fk_text text references t2(textid)
+        );
+        insert into maintable (id, fk_integer, fk_text) values (1, 1, 'a');
+        insert into maintable (id, fk_integer, fk_text) values (2, 3, 'b'); -- invalid fk_integer
+        insert into maintable (id, fk_integer, fk_text) values (3, 2, 'c'); -- invalid fk_text
+    """
+    )
+    response = await ds.client.get("/db_2214/maintable.csv?_labels=1")
+    assert response.status_code == 200
+    assert response.text == (
+        "id,fk_integer,fk_integer_label,fk_text,fk_text_label\r\n"
+        "1,1,one,a,alpha\r\n"
+        "2,3,,b,beta\r\n"
+        "3,2,two,c,\r\n"
+    )
+
+
 def test_table_csv_blob_columns(app_client):
     response = app_client.get("/fixtures/binary_data.csv")
     assert response.status == 200