TYPO3 Core

Entering date and/or time into the BE form results in wrong date going into database. Value is always incremented by user's timezone offset. When it is loaded next time, value is incremeneted by server's timezone offset and it will be shown even more in the future. Saving it adds more offset to the future.

This affects all date time fields: extension's defined or starttime/endtime.

The solution is to remove new code that appeared in 4.2.

Here is what was found during investigation (copied from http://support.typo3.org/index.php?id=17&tx_nntpreader_pi1[nid]=2&tx_nntpreader_pi1[mid]=326796&cHash=44acdb9066 ):
0. User, who is in UTC+2 time zone, opens new/edit form for the record with datetime field in it. Any startime/endtime will do. Let's use $TIME for indication of current _local time.
1. New datetime value is entered or checkbox is checked near datetime control
2. jsfunc.tbe_editor.js _substructs the value of "getTimezoneOffset()" from $TIME and stores result in hidden form field. Value of "getTimezoneOffset()" is "-2h" for UTC+2. Due to substruction we now have $TIME+2h in the hidden form now. It is important, so I repeat: we have local time + 2h in the hidden form field. This is time in future. Wonder why this is done? Read on.
3. User leaves datetime input control. Now jsfunc.evalfield.ls is called. It takes value from step 2 ($TIME+2h) and uses getUTC* functions to get... yes, $TIME. I repeat: it uses getUTC* functions but gets local time, not UTC (due to step 2).
4. Value calculated at step 3 is set back to control. So visible control shows proper local time. Hidden control still keeps value of future time ($TIME+2h).
5. User saves the form
6. Wrong value of $TIME+2 gets into the database.
7. Form loads again
8. t3lib/class.t3lib_tceforms.php adds date('O')/100 to the date value from database ($TIME+2h in the datbase). Now this value becomes localtime+4
9. form loads, go to step 2. If you did not realize it yet, time value in the form is $TIME+2h and value in the hidden field is $time+4h now. What happens if save form again? You are right if you think that time value jumps teo hours ahead. Save it 12 times and you are in the next day
(issue imported from #M7626)