From: Tom Lane <tgl@sss.pgh.pa.us>
To: Pavel Stehule <pavel.stehule@gmail.com>
cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>,
        PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: bugfix: BUG #15477: Procedure call with named inout refcursor
 parameter - "invalid input syntax for type boolean"
In-reply-to: <26116.1541278051@sss.pgh.pa.us>
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Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
	message dated "Sat, 03 Nov 2018 16:47:31 -0400"
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Date: Sat, 03 Nov 2018 17:47:04 -0400
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I wrote:
> I'm going to go see about converting this to just call
> expand_function_arguments and then drop all the special-case code.

So while looking at that ... isn't the behavior for non-writable output
parameters basically insane?  It certainly fails to accord with the
plpgsql documentation, which shows an example that would throw an error:

	CREATE PROCEDURE triple(INOUT x int)
	...
	CALL triple(5);

It's even weirder that you can get away with not supplying a writable
target value for an output argument so long as it has a default.

I think the behavior here ought to be "if the actual argument is a plpgsql
variable, assign the output back to it, otherwise do nothing".  That's
much closer to the behavior of OUT arguments in other old-school
programming languages.

			regards, tom lane