When Does print_r() Cause DateTime Objects to Gain Phantom Properties?

print_r() Function and DateTime Objects: Adding Phantom Properties

In PHP 5.3, the print_r() function can cause DateTime objects to acquire additional properties that are not explicitly defined in the class. Consider the following code example:

<code class="php">$m_oDate = new DateTime('2013-06-12 15:54:25');
print_r($m_oDate);</code>

The output of this code will include additional properties, such as "date", that are not visible by default.

However, if the same object is accessed directly, these properties will be undefined:

<code class="php">$m_oDate = new DateTime('2013-06-12 15:54:25');
echo $m_oDate->date;</code>

This inconsistency arises from a change in the PHP 5.3 internals to facilitate debugging by providing additional information about the timestamp stored within DateTime objects. This leads to the creation of phantom public properties when the object is dumped to text.

To avoid this issue, it is recommended to use reflection or the appropriate DateTime methods to access the desired information instead. Here are some examples:

• $obj->date

  • Use $obj->format('Y-m-d H:i:s') instead.

• $obj->timezone

  • Use $obj->getTimezone()->getName(), $obj->getTimezone()->getOffset(), or $obj->getTimezone()->listAbbreviations() instead.

Note that the "timezone_type" property is not accessible through the PHP API as it is an internal value related to the string representation of the timezone.

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