@test successful and thank you, bembelimen! Before the patch I got "Warning: DateTime::setTimezone() expects parameter 1 to be DateTimeZone, null given" when using the DatePeriod in my component.
After applying the patch, the Warning disappeared

Hi

What code we need to run in order to seeing the error? Look at JDate class, I see $gmt property is already initialized in contructor https://github.com/joomla/joomla-cms/blob/staging/libraries/joomla/date/date.php#L84, so I don't know when it is empty and cause the warning?

Hello,

don't ask me why, but the PHP class "DatePeriod" delivers a JDate object when you use the Traversable property (=> foreach ($dateperiod ...)) and the first parameter (http://php.net/manual/en/dateperiod.construct.php) is a JDate object. If you try to use ->format(...), the JDate method will be used and then this error appears...

Hi

As I mentioned before, the self::$gmt is initialized when a JDate object is created, so I don't know in what case it is empty. Could you provide sample code which we can run to prove this error?

After several months without further reply to the request for further information this issue is being closed. It can always be re-opened

I can confirm issue, use this gist code

You will see something like this:

object(JDate)#341 (4) { ["tz":protected]=> NULL ["date"]=> string(26) "2015-10-08 10:00:26.000000" ["timezone_type"]=> int(2) ["timezone"]=> string(3) "GMT" }

Warning: DateTime::setTimezone() expects parameter 1 to be DateTimeZone, null given in pathwww/libraries/joomla/date/date.php on line 321

Edit: added a fix without need to change core code (eg: JDate class); see comments in gist.

Thank you - sorry that I did not post the code which caused the warning for me, it is too much. Could you please test with bembelimen's patch? It worked for me also when I updated to 3.4.4 and solves the problem for me.

@test patch fix the notice

before:

object(JDate)#324 (4) { ["tz":protected]=> NULL ["date"]=> string(26) "2015-10-08 08:30:00.000000" ["timezone_type"]=> int(2) ["timezone"]=> string(3) "GMT" } 
Warning: DateTime::setTimezone() expects parameter 1 to be DateTimeZone, null given in pathwww/libraries/joomla/date/date.php on line 321

after:

object(JDate)#324 (4) { ["tz":protected]=> NULL ["date"]=> string(26) "2015-10-08 08:30:00.000000" ["timezone_type"]=> int(2) ["timezone"]=> string(3) "GMT" } 

Just want to point out, after patch tz can be null, did this really good?

@chmst see that to a workaround: how JHtml date handle date
-> set timezone based on user config or general config

@Devportobello - thank you! I'll try this.

It works. I put the example code of the gist code and write it in index.php of the template. After saving I got [Warning: DateTime::setTimezone() expects parameter 1 to be DateTimeZone] and after patch the warning disappears.

Restarted Travis build to see if tests pass (I expect them to pass). Looks fine from review.

I have tested this item successfully on bc71688

Tested with the provided instructions / code - workes as described.

Thanks. --> RTC for 3.4.6

Travis don't fails on this PR is fails on different