Wrong usage of $gmt parameter in date_i18n() in options-general.php

[swissspidy]

For showing the universal time on the "General Settings" screen, the following code is used:

date_i18n( $timezone_format, false, 'gmt' )

However, the third parameter, $gmt is actually a boolean has been that way ever since 0.71.

It should therefore look like this:

date_i18n( $timezone_format, false, true )

It currently only works because of this line in date_i18n, where gmt is implicitly true and thus gmdate is used:

$datefunc = $gmt? 'gmdate' : 'date';

Introduced in [9616].

[jdgrimes]

Actually, there is no difference between date() and gmdate() in WordPress, so that line can be removed. At the time WordPress was experimenting with setting the default PHP time based on the site's timezone, but in the end it was decided to just always have the default timezome be UTC/GMT. Which means that date() and time() always return UTC values, and thus using gmdate() is unnecessary. (I discovered this just the other day when I was researching a date/time-related bug in a plugin.) See #9588 and [12727].

I'd suggest that every reference to gmdate() in core be changed to date() to avoid this confusion.

[jdgrimes]

Note that the $gmt parameter is still needed for these lines in date_i18n():

<?php
    if ( false === $i ) {
        if ( ! $gmt )
            $i = current_time( 'timestamp' );
        else
            $i = time();
        // we should not let date() interfere with our
        // specially computed timestamp
        $gmt = true;
    }

However, they could be simplified to just:

<?php
    if ( false === $i ) {
        $i = current_time( 'timestamp', $gmt );
    }

I guess maybe we'll want to open a separate ticket for that though.

[swissspidy]

Feel free to open a new ticket for that :-) Such a change would need lots of tests beforehand though.

Simplifying date_i18n would probably also help for #18146.

[fronaldaraujo]

Passing true instead of 'gmt'

[fronaldaraujo]

Attached a patch that fixes the last parameter.

[jorbin]

In 38502:

Administration: Use a bool when when a bool is called for

The third parameter of date_i18n is a bool. Currently, it's a weak check, otherwise the call showing the universal time on the "General Settings" screen would be messed up. Use an actual bool so we call our own functions correctly.

Fixes #37634.
Props fronaldaraujo.

[jdgrimes]

Replying to swissspidy:

Feel free to open a new ticket for that :-) Such a change would need lots of tests beforehand though.

Simplifying date_i18n would probably also help for #18146.

I've opened #37910.