PHP错误的DateTime :: diff()返回错误的DateInterval

我有两个日期时间差异的问题.以下是显示DateInterval对象的命令行：

php -r "\$a = new Datetime('first day of 4 months ago midnight'); \$b = new Datetime('first day of 1 month ago midnight'); var_dump(\$a->diff(\$b));"

这里是DateInterval输出：

class DateInterval#3 (15) {
  public $y =>      int(0)
  public $m =>      int(3)
  public $d =>      int(3)
  public $h =>      int(0)
  public $i =>      int(0)
  public $s =>      int(0)
  public $weekday =>               int(0)
  public $weekday_behavior =>      int(0)
  public $first_last_day_of =>     int(0)
  public $invert =>                int(0)
  public $days =>                  int(92)
  public $special_type =>               int(0)
  public $special_amount =>             int(0)
  public $have_weekday_relative =>      int(0)
  public $have_special_relative =>      int(0)
}

编辑：第一个和第二个Datetime：

class DateTime#1 (3) {
  public $date =>
  string(19) "2014-03-01 00:00:00"
  public $timezone_type =>
  int(3)
  public $timezone =>
  string(13) "Europe/Zurich"
}

class DateTime#2 (3) {
  public $date =>
  string(19) "2014-06-01 00:00:00"
  public $timezone_type =>
  int(3)
  public $timezone =>
  string(13) "Europe/Zurich"
}

注意3天！我使用的是PHP 5.5.8,但我确信这个DateInterval前几天有0个月. DateInterval在PHP 5.4.28和5.5.14中输出0天.我不确定PHP版本是否有效.

在这两种情况下,天属性为92.

解决方法:

提供对Paul T. Rawkeen’s answer的深入了解,DateTime :: diff的问题在于它首先是converts the timezone to UTC before computation.

<?php

$zurich = new DateTimeZone('Europe/Zurich');
$utc = new DateTimeZone('UTC');

$a = new DateTime('first day of 4 months ago midnight',$zurich);
$b = new DateTime('first day of 1 month ago midnight',$zurich);

var_dump($a,$b);

$a->setTimezone($utc);
$b->setTimezone($utc);

var_dump($a,$b);

?>

给出以下内容：

object(DateTime)[3]
  public 'date' => string '2014-03-01 00:00:00' (length=19)
  public 'timezone_type' => int 3
  public 'timezone' => string 'Europe/Zurich' (length=13)
object(DateTime)[4]
  public 'date' => string '2014-06-01 00:00:00' (length=19)
  public 'timezone_type' => int 3
  public 'timezone' => string 'Europe/Zurich' (length=13)
object(DateTime)[3]
  public 'date' => string '2014-02-28 23:00:00' (length=19)
  public 'timezone_type' => int 3
  public 'timezone' => string 'UTC' (length=3)
object(DateTime)[4]
  public 'date' => string '2014-05-31 22:00:00' (length=19)
  public 'timezone_type' => int 3
  public 'timezone' => string 'UTC' (length=3)

3天的差异现在非常明显,在时区从Europe / Zurich转换为UTC后,日期分别为2014-02-28 23:00:00和2014-05-31 22:00:00 $a和$b分别.

解决方案是完全使用UTC并在显示DateTime之前进行转换：

<?php

$zurich = new DateTimeZone('Europe/Zurich');
$utc = new DateTimeZone('UTC');

$a = new DateTime('first day of 4 months ago midnight',$utc);
$b = new DateTime('first day of 1 month ago midnight',$utc);

var_dump($a,$b);

$a->setTimezone($zurich);
$b->setTimezone($zurich);

var_dump($a,$b);

?>

请注意,所有日期现在都是01,尽管时间现在有点不同(请参阅本答案末尾的注释)：

object(DateTime)[3]
  public 'date' => string '2014-03-01 00:00:00' (length=19)
  public 'timezone_type' => int 3
  public 'timezone' => string 'UTC' (length=3)
object(DateTime)[4]
  public 'date' => string '2014-06-01 00:00:00' (length=19)
  public 'timezone_type' => int 3
  public 'timezone' => string 'UTC' (length=3)
object(DateTime)[3]
  public 'date' => string '2014-03-01 01:00:00' (length=19)
  public 'timezone_type' => int 3
  public 'timezone' => string 'Europe/Zurich' (length=13)
object(DateTime)[4]
  public 'date' => string '2014-06-01 02:00:00' (length=19)
  public 'timezone_type' => int 3
  public 'timezone' => string 'Europe/Zurich' (length=13)

要对此现象提供一些见解,请注意以下事项：

>二月有28天(2014年)
>可能有31天
>夏令时开始于3月30日：01：00
> Europe / Zurich是UTC 02:00

从欧洲/苏黎世转换为UTC时,必须考虑的不仅仅是年,月和日,还要考虑小时,分钟和秒.如果这是除了任何一个月的第一天之外的任何其他日期,则不会发生此问题,但是时间仍然是23:00和22:00(在上面的示例之前).

标签：php,datetime,dateinterval
来源： https://codeday.me/bug/20190825/1714432.html