Fractional JSON numbers evaluate as false in IF and WHERE

MariaDB 12.3.3 evaluates nonzero fractional JSON numbers as false when they are used directly as boolean expressions. The same values are nonzero numerically, and ordinary fractional numeric literals evaluate as true.

This occurs when a fractional JSON number is evaluated directly as a boolean expression, including in IF or WHERE.

Steps to reproduce

1. Run the following statements in one MariaDB session. They create no persistent state.

SELECT 'fraction' AS case_name,

 IF(JSON_EXTRACT('0.5','$'),1,0) AS actual,

 IF(0.5,1,0) AS expected,

 JSON_EXTRACT('0.5','$') <> 0 AS numeric_nonzero;

SELECT 'negative_fraction' AS case_name,

 IF(JSON_EXTRACT('-0.5','$'),1,0) AS actual,

 IF(-0.5,1,0) AS expected;

SELECT 'zero' AS case_name,

 IF(JSON_EXTRACT('0','$'),1,0) AS actual,

 0 AS expected;

SELECT 'json_true' AS case_name,

 IF(JSON_EXTRACT('true','$'),1,0) AS actual,

 1 AS expected;

SELECT 'json_false' AS case_name,

 IF(JSON_EXTRACT('false','$'),1,0) AS actual,

 0 AS expected;

SELECT 'predicate' AS case_name,

 COUNT(*) AS actual,

 1 AS expected

FROM (SELECT 1 AS n) AS row_source

WHERE JSON_EXTRACT('0.5','$');

Actual result

case_name          actual  expected  numeric_nonzero

fraction           0       1         1

case_name          actual  expected

negative_fraction  0       1

zero               0       0

json_true          1       1

json_false         0       0

predicate          0       1

Both 0.5 and -0.5 extracted from JSON evaluate as false. The WHERE predicate also discards its row. The numeric comparison reports that the extracted 0.5 is nonzero, while the zero and JSON-boolean controls return their expected values.

Expected result

A nonzero numeric scalar should evaluate as true regardless of whether it originated as a JSON number. The positive and negative fraction queries should therefore return actual = 1, and the WHERE query should count one row.

The source-level hypothesis from the reproducer is that JSON boolean evaluation uses an integer conversion that loses the fractional part before testing the value.