[Maria-developers] Review request[major 5.3/5.5 bug]: MDEV-4511 Assertion `scale <= precision' fails on GROUP BY TIMEDIFF with incorrect types, , Agile Board, , Export

Hello Sergei, A few weeks ago we fixed this bug for 10.0 by changing temporal items not to have decimals=NOT_FIXED_DEC (more MySQL-5.6 compatibility), and agreed to have a separate patch for the pre-10.0 branches. This patch is for 5.3 and 5.5 only. It back-ports the mdev-4511 tests from 10.0 as is. But it does not touch the NOT_FIXED_DEC behavior of the temporal items and fixes the problem in a different way. Greetings.