Edit report at https://bugs.php.net/bug.php?id=76848&edit=1
ID: 76848
Comment by: wojciech dot mocek at gmail dot com
Reported by: wojciech dot mocek at gmail dot com
Summary: Possible to create Datetime from wrong month day
Status: Not a bug
Type: Bug
Package: Date/time related
Operating System: Linux
PHP Version: 7.1.21
Block user comment: N
Private report: N
New Comment:
You asked "should both evaluate to the same value, shouldn't they?". So the answer
is: no, they should not.
This is how it was solved in other object language:
$ docker container run --rm -it openjdk jshell
Oct 25, 2019 11:21:53 PM java.util.prefs.FileSystemPreferences$1 run
INFO: Created user preferences directory.
| Welcome to JShell -- Version 13.0.1
| For an introduction type: /help intro
jshell> var dateA = java.time.LocalDate.parse("2018-01-31");
jshell> dateA.plusMonths(1)
$2 ==> 2018-02-28
jshell> var dateB = java.time.LocalDate.parse("2018-02-31");
| Exception java.time.format.DateTimeParseException: Text '2018-02-31' could not be
parsed: Invalid date 'FEBRUARY 31'
(...)
Do you agree that PHP DateTime class is class for handling date and time? If yes, then do you agree
that it should behave according to real date&time? If yes, then do we have in our calendar date
'2018-02-31'?
Previous Comments:
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[2018-11-21 15:10:06] cmb@php.net
Obviously,
new DateTime('2018-01-31 +1 month')
and
new DateTime('2018-02-31')
should both evaluate to the same value, shouldn't they?
------------------------------------------------------------------------
[2018-11-21 15:05:30] wojciech dot mocek at gmail dot com
What is the correlation between your question and reported bug?
------------------------------------------------------------------------
[2018-11-21 12:43:28] cmb@php.net
And how should the following be handled?
new DateTime('2018-01-31 +1 month')
------------------------------------------------------------------------
[2018-11-21 11:06:29] wojciech dot mocek at gmail dot com
Open.
------------------------------------------------------------------------
[2018-09-11 11:44:56] wojciech dot mocek at gmai dot com
You wrote:
1. "That's right, it does not validate the date."
Well, hmm, I just run script:
$ php <<< "<?php var_dump(new \Datetime('2018-09-32'), new
\Datetime('2018-02-32'));"
PHP Fatal error: Uncaught Exception: DateTime::__construct(): Failed to parse time string
(2018-09-32) at position 9 (2): Unexpected character in Standard input code:1
Stack trace:
#0 Standard input code(1): DateTime->__construct('2018-09-32')
#1 {main}
thrown in Standard input code on line 1
So it looks that is validates given input somehow.
2. "It tries its best to come up with the most reasonable interpretation of the string passed
to it. Just like how strtotime does.". Come on, please ask people around to do something on
"2018-02-31", I think noone will think to do it on "2018-03-03" My question #2
is: do you say that if tell me "Send this mail on 2018-02-31" it is MOST REASONABLE to
interpret this as "send it on 2018-03-03" ?!
3. "It tries its best to come up with the most reasonable interpretation of the string passed
to it. Just like how strtotime does." . You mentioned about strtotime:
$ php <<< "<?php var_dump(strtotime('2018-02-31'));"
int(1520035200)
$ php <<< "<?php var_dump(strtotime('2018-02-32'));"
bool(false)
$ php <<< "<?php var_dump(new \Datetime('2018-02-32'));"
PHP Fatal error: Uncaught Exception: DateTime::__construct(): Failed to parse time string
(2018-02-32) at position 9 (2): Unexpected character in Standard input code:1
Stack trace:
#0 Standard input code(1): DateTime->__construct('2018-02-32')
#1 {main}
thrown in Standard input code on line 1
- 31 of February - there is no such date ever in calendar, but PHP creates time.
- 32 of February - also there is no such date ever in calendar, PHP forbids to create time
"It tries its best to come up with the most reasonable interpretation of the string passed to
it" - if it is possible to create time from "never existing 31 of February", so why
it is not possible to create time from also "never existing 32 of February" ?
3. In normal life we cannot do anything on 31 of February, nor 31 of September. If you write
business application for invoicing, banks, anything, you must validate the date. And if someone
writes 31 of February to for example pay tax or send cash, it is mistake and NOT REASONABLE to
process. So "day of month" validation should be implemented. Otherwise all business
applications will have to use some custom PHP date library, only because native PHP allows to create
such nonsense like date from '2018-02-31'.
------------------------------------------------------------------------
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https://bugs.php.net/bug.php?id=76848
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