BUG on addMonth

[minkbear]

if Today = 2017-03-29
and Today - 1 month = should be 2017-02-28 (expected end of last month)

Here is code

dd(Carbon::now())

Carbon\Carbon {#1352
  +"date": "2017-03-29 13:22:21.000000"
  +"timezone_type": 3
  +"timezone": "Asia/Bangkok"
}

dd(Carbon::now()->addMonth(-1))

Carbon\Carbon {#1352
  +"date": "2017-03-01 13:23:31.000000"
  +"timezone_type": 3
  +"timezone": "Asia/Bangkok"
}

[bramslob]

Same here, but with Carbon::now()->subMonth(1)->startOfMonth() returning :

Carbon\Carbon {#1341
     +"date": "2017-03-01 00:00:00.000000",
     +"timezone_type": 3,
     +"timezone": "Europe/Amsterdam",
}

[HercDotMe]

If you can disregard the day and need to check only months and years you can do: Carbon::now()->startOfMonth()->subMonth(1) which will return the first day of last month.

[bramslob]

@VladErc sadly I do need to work with the day. But as you can see in my comment, I did do the startOfMonth() but that still returned march

[HercDotMe]

@bramslob You did it the other way (first subMonth then startOfMonth), which, due to the bug, would've returned 1st of March and then take first of that month. My way gets you to first of March and then subtracting a month which will return 1st of February.

[bramslob]

@VladErc I see yes, that does work. But I do believe this is unintended behavior. The order in this should not matter. But thanks for showing a way in which it works for now

[leepownall]

#639
#761

Carbon::now()->subMonth() -> Carbon::now()->subMonthNoOverflow()
Carbon::now()->addMonth() -> Carbon::now()->addMonthNoOverflow()

Had same issue, not sure what the underlying reason is, but here is the fix.

[bramslob]

@leepownall found that option in the source as well, but did not see the explanation of 'overflow'. Now that you pointed to those issues I get it a lot more. Thanks, I guess we'll change our code accordingly

[HercDotMe]

@leepownall I would've expected default behaviour to be with no overflow, thanks for the fix however!

[DanielDarrenJones]

I also feel like the default behaviour should be changed to include the overflow, I was not aware of this until I saw a tweet about it just now and this would have certainly caught me out.

[dereuromark]

@DanielDarrenJones https://github.com/cakephp/chronos has the default behavior built in as expected.
For Carbon it would require a major bump in version.

[DanielDarrenJones]

@dereuromark ooo thanks for sharing that, it seems to cover some of the shortfalls I didn't like with carbon such as immutability, will defo give that a go 😄

[lucasmichot]

@minkbear then use addMonthsNoOverflow

[lucasmichot]

And have a look at \Carbon\Carbon::useMonthsOverflow