PHP Carbon "month()" method generates wrong DateTime

I just stumbled upon something really weird. I use the "Carbon" package to generate DateTime objects.

I use the following code to create a DateTime string for the beginning of September 2016:

Carbon::create()->month(9)

If I output this using Laravel's "dd()" function, I receive the following output:

Carbon\Carbon {
  +"date": "2016-10-01 10:22:36.000000"
  +"timezone_type": 3
  +"timezone": "Europe/Vienna"
}

It returns the 1st of October, rather than the 1st of September! It works fine with every other month.

Ive also tried these:

Carbon::now()->month(9)
(new Carbon)->month(9)

But I get the same wrong result.

Does anyone else experience this bug or can someone please try this out and tell me if you receive the same output? Or am I just doing something wrong, even though I can't think of anything?

Thanks in advance.

Solution

I guess that the problem is todays date which is the 31st.

Carbon::create()->month(9) tries to take the same day for September. Since there is no 31st in September, it returns October 1st. Try:

Carbon::create()->day(1)->month(9);

Carbon::create()->startOfMonth()->month(9);

Carbon::create(null, 9);