I can't get passive creature controls to work. The following code for spawn.json still allows passive creatures to spawn on blocks other than what I specify. This is in vanilla forge 2226 for mc 1.11.2. If there is additional code needed to control the spawning, could you let me know?

Thanks,
(spawn.json)
[
{
"passive": true,
"result": "deny"
},
{
"passive": true,
"block": ["minecraft:stone"],
"result": "allow"
},
{
"result": "deny"
}
]

Here's a picture of them still spawning on grass:

I think this is due to passive mob spawning being separated into two parts: on chunk loading first time, and normal spawning.

We are having this issue as well incontrol-3.5.2 for 1.10.2. We have Aroma mining dimension blacklisted for all passive spawns. With debug mode on we see it preventing squid and bat spawns but things like cows/sheep/chickens etc. still spawn.

[
{
"passive": "true",
"dimension": 6,
"result": "deny"
}
]

http://imgur.com/a/tgR35

You must use "onjoin": true if you also want to stop passive mobs from being generated during chunk generation.

@Timeslice42 Thanks a lot for the answer!!

@McJty Thanks a lot for the mod!!

I got the following to work for spawning only rabbits:

[
  {
    "passive": true,
    "mob": "minecraft:rabbit",
    "result": "allow"
  },
  {
    "passive": true,
    "mob": "minecraft:rabbit",
    "onjoin": true,
    "result": "allow"
  },
  {
    "passive": true,
    "onjoin": true,
    "result": "deny"
  },
  {
    "result": "deny"
  }
]