CREATE FUNCTION foo (VARIADIC anyarray) RETURNS void AS $$ DECLARE BEGIN END $$ LANGUAGE plpgsql; SELECT foo (ARRAY[1]);
I would expect an error: Like: ERROR: function f3oo(integer[]) does not exist
But I get this error: ERROR: could not find array type for data type integer[]
Why VARIADIC functions are found on array input? In my opinion it makes no sense and the disadvantage is that overloading with a function like: CREATE OR REPLACE FUNCTION foo (anyarray) doesn't work.
A variadic functions are exception in mechanism, how postgres choose any specific function. Usually parser try to search function with same name and most similar parameter types list. Variadic functions works differently - we try to dynamically prepare parameter list to be able consume values specified by caller. This mechanism has some corner cases - we are not able detect all possible ambiguous parameters in creation time, and some times it raises little bit unclean messages, but generally it works well - but every enhancing is welcome