I have been doing redstone for a project that I started since the 1.8 snapshots. Since the third to last snapshot came out, I started to experience problems with command blocks using the command: "/execute @p[score_Spear_min=6,ry=92,rym=88] ~ ~ ~ /testfor @p[ry=92,rym=88]" which leads a comparator output to a command block doing: "/execute @p[score_Spear_min=6] ~ ~ ~ /summon Arrow ~-1 ~1 ~

". There is another command block set next to it with the same commands, except that the ry and the rym are both negative, and the arrow is summoned at ~1 ~1 ~ and a positive motion. When one gets activated, it activates both sets and summon two arrows going in opposite directions.

From MC-78450:
The target selectors ry= and rym= appear to be broken. I tested the following target selectors with both @p and @a in both a command block and in the chat bar.

[ry=-90]
Applies to targets with Horizontal Rotation greater than 0 or less than -89.0 (including all positive numbers)
This target selector is supposed to select only targets with a maximum Horizontal Rotation of -90

[ry=90]
Applies to targets with Horizontal Rotation between 0.1 to 90.9
This target selector is supposed to select only targets with a maximum Horizontal Rotation of 90

rym=90
Applies to targets with Horizontal Rotation greater than 90.0 or less than 0.1 (including all negative numbers)
This target selector is supposed to select only targets with a minimum Horizontal Rotation of 90

rym=-90
Applies to targets with Horizontal Rotation between 0 and -89.9
This target selector is supposed to select only targets with a minimum Horizontal Rotation of -90