Conditional functions with constant expression as condition should evaluate only one branch

[vpanfilov]

For example, if I use UInt8 constant for if condition then only one branch is evaluated:

SELECT if(1, 'success', throwIf(1, 'Executing FALSE branch'))

┌─'success'─┐
│ success   │
└───────────┘

1 rows in set. Elapsed: 0.003 sec.

But if I use some constant expression, then both branches are evaluated:

SELECT if(empty(''), 'success', throwIf(1, 'Executing FALSE branch'))

0 rows in set. Elapsed: 0.003 sec.

Received exception from server (version 21.12.2):
Code: 395. DB::Exception: Received from localhost:9000. DB::Exception: Executing FALSE branch: While processing if(empty(''), 'success', throwIf(1, 'Executing FALSE branch')). (FUNCTION_THROW_IF_VALUE_IS_NON_ZERO)

[den-crane]

hm,

SELECT if(empty(''), 1, sleep(1));
Elapsed: 0.001 sec.

SELECT if(empty(''), 1, toDecimal64(1,2)/0);
DB::Exception: Division by zero:


SELECT if(x = '', 1, toDecimal64(1, 2) / 0)
FROM
(
    SELECT materialize('') AS x
)
DB::Exception: Division by zero:

[kitaisreal]

Cannot be implemented until #23194.