[1.21.1 / 0.8] Weak Automata targets its own turtle again (regression of #698)

[cmoyates]

Describe

Possible regression of #698 on the 1.21.1 / 0.8 line: a Weak Automata Core targets its own turtle instead of the block in front. lookAtBlock({yaw=0,pitch=0}) non-destructively confirms the self-hit. An earlier digBlock call interrupted the turtle immediately, and the player observed it apparently mining itself; we stopped destructive testing and verified the target with lookAtBlock instead.

Expected: zero relative yaw/pitch looks forward past the source turtle and reports the front block.

Observed on installed AP 1.21.1-0.8.0a: turtle.inspect() reports ars_controle:scryers_linkage, while the core reports computercraft:turtle_normal at a hit point approximately 0.0045 blocks forward of the turtle center. Turtle was stationary and facing north. Fuel, selected slot, inventory fingerprints and pickaxe damage were unchanged by the look diagnostic.

I searched existing issues/PRs. #698 is closed as completed and concerns an earlier development build. I did not find an open matching report for the current 0.8 line.

Steps to reproduce

1. In the reported setup, use a normal turtle with Weak Automata Core on the left (Chunky on the right). Keep the turtle stationary, facing north, with a Scryer's Linkage directly in front. The linkage in this setup forwards a barrel inventory; turtle.inspect() verifies its physical block identity.
2. Perform this non-destructive targeting check (no pickaxe or dig call needed):

local present, front = turtle.inspect()
assert(present, "Place a block directly in front first")
local core = assert(peripheral.wrap("left"))
print("Physical front: " .. front.name)
local hit, err = core.lookAtBlock({ yaw = 0, pitch = 0 })
print(textutils.serialize(hit or { error = err }))

3. Compare the front block with the ray result. The equivalent single-call diagnostic in our test returned:

-- turtle.inspect():
{ name = "ars_controle:scryers_linkage", state = {} }

-- core.lookAtBlock({yaw=0, pitch=0}), relevant fields:
{
  name = "computercraft:turtle_normal",
  x = 0, y = 0, z = -0.0045000000000001705,
  r = 0, u = 0, f =  0.0045000000000001705
}

Please use the look-only reproduction rather than digBlock on a valuable turtle. Look is non-destructive, not strictly side-effect-free: it updates the upgrade animation charge and round-trips the fake-player inventory. We observed no fuel/item/durability changes during this diagnostic.

Source investigation / newer-version check

Live reproduction is 0.8.0a only. We have not installed or live-tested 0.8.1a or a development build. However, the same apparent missing source exclusion remains in the 0.8.1a tag (02868e922b9a4a1af91cadaaf835c51bd016cfe6) and dev/0.8-1.21.1 (67a8a687189a6eeb14eb8d7fe75d8a5b87f2c948) as checked for this report:

• FakePlayerProviderTurtle.load at the current 0.8 development commit positions the fake player at (turtle.x+0.5, turtle.y+0.5, turtle.z+0.5) with the turtle's facing, but does not call setSourceBlock.
• APFakePlayer initializes source = null and exposes a setter. findHit passes that source into the block clipper.
• HitResultUtil.AdvancedClipContext.getBlockShape skips a block only if source != null && source.equals(pPos).
• The ray origin is inside the turtle outline. Installed-bytecode review shows both lookAtBlock and digBlock use findHit(true, false); no later self-block exclusion protects digging. A scan of the installed AP 0.8.0a class files found the setter definition but no callers.
• 0.8.1a release provider likewise does not set the source block. The default dev/1.21.1 branch uses a different, older clipping implementation that explicitly skips blockPosition(); it should not be confused with the 0.8 release/development line.

Likely fix direction: initialize/refresh the source-block exclusion from the turtle's current position whenever loading the fake player, and add regression coverage for self-hit exclusion, including after movement. This is a source-based suggestion, not a patch we have tested.

Multiplayer?

No — single-player integrated server.

Version

Other. (probably unsupported): 1.21.1-0.8.0a, installed AdvancedPeripherals-1.21.1-0.8.0a.jar. The issue form no longer lists this release. The newer 0.8.1a and 0.8 development source were inspected as noted above, not live-tested.

Minecraft, Forge and maybe other related mods versions

• Minecraft 1.21.1
• NeoForge 21.1.249
• CC: Tweaked 1.120.2, confirmed by live _HOST: ComputerCraft 1.120.2 (Minecraft 1.21.1)
• Ars Controle 1.21.1-1.6.15 (physical front block)
• All the Mods 10 installation; not yet reproduced in a clean minimal pack
• For transparency, the pack directory contains both CC 1.113.1 and 1.120.2 JARs; the live runtime identifies 1.120.2. No mods/configs were changed to obtain this result.

Screenshots or Videos

None. Normalized output from the actual non-destructive diagnostic is included above.

Crashlog/log

No JVM crash was observed. The original dig test's last checkpoint was its first dig intent, followed by loss of turtle heartbeat; on return, the supervisor reported the test interrupted and did not rerun it. The subsequent look-only diagnostic completed and failed its safety check with UNSAFE: core ray hits a turtle instead of the front linkage, lookCalls=1, hitsTurtle=true, and unchanged inventory/fuel/selection/front block. Private filesystem paths and unrelated full modpack logs are omitted.