php strtotime "last monday" if today is monday?

I want to use strtotime("last Monday").

The thing is, if today IS MONDAY, what does it return? It seems to be returning the date for the monday of last week. How can I make it return today's date in that case?

If you read the manual, there is an great example that describes exactly what you want to do http://www.php.net/manual/en/datetime.formats.relative.php

strtotime('Monday this week');

Update: There appears to be a bug introduced in newer versions of PHP where this week returns the wrong week when ran on Sundays. You can vote on the bug here: https://bugs.php.net/bug.php?id=63740

Update 2: As of May 18th 2016, this has been fixed in PHP 5.6.22, PHP 7.0.7 and PHP 7.1-dev (and hopefully remains fixed in subsequent releases) as seen here: https://bugs.php.net/bug.php?id=63740#1463570467

How can I make it return today's date in that case?

pseudocode:

if (today == monday)
    return today;
else
    return strtotime(...);

Btw, this trick also could work:

strtotime('last monday', strtotime('tomorrow'));

If today is Monday, strtotime("last Monday") will return a date 7 days in the past. Why don't you just check if today is Monday and if yes, return today's date and if not, return last week?

That would be a foolproof way of doing this.

if (date('N', time()) == 1) return date('Y-m-d');
else return date('Y-m-d', strtotime('last Monday'));

http://us2.php.net/manual/en/function.date.php

As it was correctly outlined in the previous answer, this trick works, but also had caveats prior to PHP 5.6.22, PHP 7.0.7 and PHP 7.1-dev:

strtotime('last monday', strtotime('tomorrow'));

// or this one, which is shorter, but was buggy:
strtotime('Monday this week');

To those, who prefer the "Jedy-way", to work with objects of the DateTime class, the solution is next:

(new \DateTime())->modify('tomorrow')->modify('previous monday')->format('Y-m-d');

or even shorter notation:

\DateTime('Monday this week')

Be carefull, because if you do the same on SQL, you don't need to have any of these tricks in mysql with addition of "tomorrow". Here's how the solution will look:

SELECT DATE_SUB(CURDATE(), INTERVAL WEEKDAY(CURDATE()) DAY) as last_monday;