Hi,
The parallel code-path isn't actually exercised in the tests added in[1], as evidenced by [2] (they just explain). That imo needs to befixed.
Greetings,
Andres Freund
[1] https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=f35742ccb7aa53ee3ed8416bbb378b0c3eeb6bb9[2] https://coverage.postgresql.org/src/backend/executor/nodeBitmapHeapscan.c.gcov.html