FloorMonth for last day of month, returns next month if month has 31 days

[atay]

Hello,

I encountered an issue with the following code:

<?php
require 'vendor/autoload.php';

use Carbon\Carbon;

function showDate($date) {
    echo "Date:" . $date->format("Y-m-d") . ", floorMonth: " . $date->copy()->floorMonth()->format("Y-m-d") . PHP_EOL;
}

$date1 = Carbon::parse("2021-03-30");
$date2 = Carbon::parse("2021-03-31");

showDate($date1);
showDate($date2);

Carbon version: 2.57.0 and 2.55.2

PHP version: 8.0.8 and 8.1.1

I expected to get:

Date:2021-03-30, floorMonth: 2021-03-01
Date:2021-03-31, floorMonth: 2021-03-01

But I actually get:

Date:2021-03-30, floorMonth: 2021-03-01
Date:2021-03-31, floorMonth: 2021-04-01

Thanks!

[atay]

Same issue with months that have 31 days:

<?php
require 'vendor/autoload.php';

use Carbon\Carbon;

function showDate($date) {
    echo "Date: " . $date->format("Y-m-d") . ", floorMonth: " . $date->copy()->floorMonth()->format("Y-m-d") . PHP_EOL;
}

for ($i = 1; $i <= 12; $i++) {
    showDate(Carbon::parse("2021-$i-01")->endOfMonth());
}

Output:

Date: 2021-01-31, floorMonth: 2021-02-01
Date: 2021-02-28, floorMonth: 2021-02-01
Date: 2021-03-31, floorMonth: 2021-04-01
Date: 2021-04-30, floorMonth: 2021-04-01
Date: 2021-05-31, floorMonth: 2021-06-01
Date: 2021-06-30, floorMonth: 2021-06-01
Date: 2021-07-31, floorMonth: 2021-08-01
Date: 2021-08-31, floorMonth: 2021-09-01
Date: 2021-09-30, floorMonth: 2021-09-01
Date: 2021-10-31, floorMonth: 2021-11-01
Date: 2021-11-30, floorMonth: 2021-11-01
Date: 2021-12-31, floorMonth: 2022-01-01 

[kylekatarnls]

This will be fixed in the next release, it can be tested using composer require "nesbot/carbon:dev-master as 2.58.0"

Thanks 🙏