I'd suggest pulling out this system view change into its own patch.
But within this thread or new one?
Thread. The subject line needs to make clear we are proposing changing a system view.
The connection limit can be set to 0. What should be displayed in this case, blank or 0?
0 or even "not allowed" to make it clear
The connection limit can be set for superusers. What should be displayed in this case,
blank or actual non-effective value?
print "# (ignored)" ?
CREATE|ALTER ROLE commands allow incorrect values to be set for 'Conn limit' and 'Valid until'.
How can the administrator see them and fix them?
That is unfortunate...but they can always go look at the actual system view. Or do what i showed above and add (invalid) after the real value. Note I'm only really talking about -1 here being the value that is simply hidden from display since it means unlimited and not actually -1
I'd be more inclined to print "forever" for valid until since the existing presentation of a timestamp is already multiple characters. Using a word for a column that is typically a number is less appealing.