pg_hint_plan_set_rel_pathlist() enforces an incorrect check for inheritance children, contrary to upstream commit d8e34fa.
Currently, parallel hints on single relations cannot be enforced properly without the GUCs related to parallelism to be reset first. Perhaps there is not much of a use-case when it comes to that, but let's add some regression tests to check this default behavior.
Hearing nothing, applied. The tests apply to all the stable branches and the check only to master as upstream includes d8e34fa only in 15~, so I have split the changes into two separate commits for clarity.
The following is done:
Per issue #102.