[Flashmyname]

Summary

setLowLODElement accepted a building as its own LOD, directly or through a chain, and the building lost its collision. Calling it on a group that holds the LOD did the same to the LOD.

Motivation

Builds on #5521.

Test plan

crun setElementPosition(localPlayer,0,0,4) k=createBuilding(1337,3,0,10) m=createBuilding(1337,3,4,10)
crun return setLowLODElement(k,k), isLineOfSightClear(3,0,13,3,0,9,true,false,false,false)
crun return setLowLODElement(m,k), setLowLODElement(k,m), isLineOfSightClear(3,4,13,3,4,9,true,false,false,false)
run a=createBuilding(8661,0,240,12) return setLowLODElement(a,a)

Master returns true, true, true, true, true and true, with the fix false, false, true, false, false and false.

Checklist

• Your code should follow the coding guidelines.
• Smaller pull requests are easier to review. If your pull request is beefy, your pull request should be reviewable commit-by-commit.

[Copilot]

🟢 Approval recommended

No active review issues remain for the client and server changes intended to prevent cyclic building LOD links.

No open issues 🎉

What changed in this PR

Builds on #5521’s building LOD-link fixes by rejecting direct and indirect LOD cycles on both the client and server, preventing the collision loss described in the PR.

Changes:

• Walk the proposed LOD chain and reject links that lead back to the current building.
• Validate before removing the existing LOD link, preserving it when a cyclic assignment is rejected.

Include the goals, reasoning, and test results in the commit message.

File	Description
Server/​mods/​deathmatch/​logic/​CBuilding.cpp	Rejects cyclic building LOD assignments before modifying server-side links.
Client/​mods/​deathmatch/​logic/​CClientBuilding.cpp	Adds matching cycle validation before modifying client-side links.

_{Review effort: Balanced}