This is because in wily, fs operations like mkfs, e2label, or other things which directly open the block device don't trigger a change event any more:
$ sudo modprobe scsi_debug $ udevadm monitor
Then run this in another terminal: sudo sh -c '> /dev/sda'
Up to vivid you get
KERNEL[40.913525] change /devices/pseudo_0/adapter0/host2/target2:0:0/2:0:0:0/block/sda (block) UDEV [41.021205] change /devices/pseudo_0/adapter0/host2/target2:0:0/2:0:0:0/block/sda (block)
In wily there is no uevent.
This is because in wily, fs operations like mkfs, e2label, or other things which directly open the block device don't trigger a change event any more:
$ sudo modprobe scsi_debug
$ udevadm monitor
Then run this in another terminal: sudo sh -c '> /dev/sda'
Up to vivid you get
KERNEL[40.913525] change /devices/ pseudo_ 0/adapter0/ host2/target2: 0:0/2:0: 0:0/block/ sda (block) pseudo_ 0/adapter0/ host2/target2: 0:0/2:0: 0:0/block/ sda (block)
UDEV [41.021205] change /devices/
In wily there is no uevent.