This bug was only present on v15. MarkGUCPrefixReserved() is new in
v15, and in v16, it was rewritten to use a hash table and the new
implementation did not have this bug.
Author: Karina Litskevich, Ekaterina Sokolova
Discussion: https://www.postgresql.org/message-id/CACiT8ibqyC=_g1n6FXyFJvFW0BEjAH3_5aGqUSFeEp8GpnVrhw@mail.gmail.com
num_guc_variables--;
memmove(&guc_variables[i], &guc_variables[i + 1],
(num_guc_variables - i) * sizeof(struct config_generic *));
+ i--;
}
}