[intl] Weird numeric sort in Collator

[arokettu]

Description

The following code:

<?php

$arr = [
    '2023-02-04 14:00:00',
    '2023-01-08 12:00:00',
    '2023-01-03 12:00:00',
    '2023-01-03 12:00:00',
    '2021-01-03 12:00:00',
    '2023-01-05 14:00:00',
    '2024-01-03 12:00:00',
    '2023-01-03 12:00:00',
];

$coll = Collator::create('de');

$coll->asort($arr, Collator::SORT_REGULAR);

echo json_encode($arr, JSON_PRETTY_PRINT);

Resulted in this output:

{
    "4": "2021-01-03 12:00:00",
    "0": "2023-02-04 14:00:00",
    "1": "2023-01-08 12:00:00",
    "2": "2023-01-03 12:00:00",
    "3": "2023-01-03 12:00:00",
    "5": "2023-01-05 14:00:00",
    "7": "2023-01-03 12:00:00",
    "6": "2024-01-03 12:00:00"
}%

But I expected this output instead:

{
    "4": "2021-01-03 12:00:00",
    "2": "2023-01-03 12:00:00",
    "3": "2023-01-03 12:00:00",
    "7": "2023-01-03 12:00:00",
    "5": "2023-01-05 14:00:00",
    "1": "2023-01-08 12:00:00",
    "0": "2023-02-04 14:00:00",
    "6": "2024-01-03 12:00:00"
}

PHP Version

Since the dawn of time up to 8.4.7 apparently introduced in PHP6(!)

https://3v4l.org/fVcRj

Operating System

any

[arokettu]

The ultimate cause seems to be collator_convert_string_to_number_if_possible thinking that it's possible to convert to number and making them all (int)2021, (int)2023, (int)2024

php-src/ext/intl/collator/collator_convert.c

Line 322 in 2e70a89

if( is_numeric == IS_LONG ) {

php-src/ext/intl/collator/collator_is_numeric.c

Line 207 in 2e70a89

uint8_t collator_is_numeric( UChar *str, int32_t length, zend_long *lval, double *dval, bool allow_errors )