Richard Beck

I see this as well

made test case with no stairs, and zombies would climb up block paths east and west, but not north or south

made a test case with stairs in each direction: the zombies would climb east and west facing stairs, but not north or south facing stairs

with the villagers all dead, the zombie does not wonder away, but still wont climb

I removed all stairs and rebuilt it one block over, no change

I have found that the zombies will climb some stairs, but in older versions they climbed these stairs too
I tried eliminating the redstone next to the path, didn't help

killed all villagers and still the same thing

My daughter pointed out that the zombie spends most of its time looking toward a village with villagers, but this dint happen in older versions, I will try killing them all

I went back to 15w51b and confirmed that I still see the same thing
not sure what other info is needed, I attached a screenshot

I was seeing this issue with render set above 12
then with 4G allocated and VOB on was ok at 32
then made new world and nothing rendered, sank to Y=0, only saw the particles that you see when Y < 6

---- Minecraft Crash Report ----
// Why did you do that?

Time: 8/10/14 9:14 PM
Description: Manually triggered debug crash

java.lang.Throwable
	at bsn.r(SourceFile:1566)
	at bsn.as(SourceFile:875)
	at bsn.a(SourceFile:312)
	at net.minecraft.client.main.Main.main(SourceFile:120)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at cee.a(SourceFile:308)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [cif['ALostDog'/40764, l='MpServer', x=-53.50, y=-0.01, z=261.50]]
	Chunk stats: MultiplayerChunkCache: 0, 0
	Level seed: 0
	Level generator: ID 04 - customized, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: -44.00,64.00,256.00 - World: (-44,64,256), Chunk: (at 4,4,0 in -3,16; contains blocks -48,0,256 to -33,255,271), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 3726 game time, 3726 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
	Forced entities: 1 total; [cif['ALostDog'/40764, l='MpServer', x=-53.50, y=-0.01, z=261.50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at cee.a(SourceFile:308)
	at bsn.b(SourceFile:2255)
	at bsn.a(SourceFile:321)
	at net.minecraft.client.main.Main.main(SourceFile:120)

-- System Details --
Details:
	Minecraft Version: 14w32d
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_65, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 272785072 bytes (260 MB) / 1694318592 bytes (1615 MB) up to 4281597952 bytes (4083 MB)
	JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx4G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
	IntCache: cache: 1, tcache: 1, allocated: 12, tallocated: 94
	Launched Version: 14w32d
	LWJGL: 2.9.1
	OpenGL: AMD Radeon HD 6530D Graphics GL version 4.1.11079 Compatibility Profile Context, ATI Technologies Inc.
	GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

	Using VBOs: Yes
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: English (US)
	Profiler Position: N/A (disabled)

I found that if you dig out an area one down and 4 to each side of the spawner, mobs don't spawn in light.
In other words its the light level at there feet that seems to count, and if they spawn with feet under a block, well its dark under the block.
Anyway it seems that no checking for blocks is happening, they can spawn in the blocks of walls and floors of a dungeon.
I tested this on a new world on 14w27b.

I see this too, Kinda makes the game unplayable at the point where you need slimes, I think this has been an issue for me for at least three patches including the latest 14w21b.
I would also like to say that finding this using the built in search is not easy, in part cause all of the old postings about slimes, and that it wont let me change the display order.