Robert Haas <robertmhaas@gmail.com> writes:
> Looking at it, this sounds suspiciously something where we could just
> test EXEC_FLAG_BACKWARD, based on the comments for that flag, but I
> wouldn't be willing to bet very much on me being right about that.
> Can somebody try to fetch backward even if this flag wasn't provided?
They're not supposed to, and it would be a bug of theirs not yours
if they did. Other node types that rely on eflags being provided
honestly generally just Assert that they're not asked for something
else later.
regards, tom lane