fix(assembly): prevent segfault when all joints are removed #310

forbes · 2026-02-21T15:47:39Z

forbes commented

2026-02-21 15:47:39 +00:00

Problem

Removing all joints from an assembly causes a segmentation fault (stack overflow).

Root Cause

updateSolveStatus() calls solve() when lastResult_.placements is empty, but solve() calls updateSolveStatus() at the end. When an assembly has zero constraints (all joints removed), the solver returns zero placements, so lastResult_.placements.empty() remains true on every call — causing infinite recursion until stack overflow.

solve() → updateSolveStatus() → solve() → updateSolveStatus() → ... → segfault

Fix

Add a static re-entrancy guard to updateSolveStatus() so the recursive solve() call is skipped when already on the call stack.

Testing

Open an assembly with joints
Remove all joints
Verify no crash — assembly should remain open with all parts unconstrained

## Problem Removing all joints from an assembly causes a segmentation fault (stack overflow). ## Root Cause `updateSolveStatus()` calls `solve()` when `lastResult_.placements` is empty, but `solve()` calls `updateSolveStatus()` at the end. When an assembly has zero constraints (all joints removed), the solver returns zero placements, so `lastResult_.placements.empty()` remains true on every call — causing **infinite recursion** until stack overflow. ``` solve() → updateSolveStatus() → solve() → updateSolveStatus() → ... → segfault ``` ## Fix Add a static re-entrancy guard to `updateSolveStatus()` so the recursive `solve()` call is skipped when already on the call stack. ## Testing 1. Open an assembly with joints 2. Remove all joints 3. Verify no crash — assembly should remain open with all parts unconstrained

forbes added 1 commit 2026-02-21 15:47:41 +00:00

fix(assembly): prevent segfault when all joints are removed

Build and Test / build (pull_request) Has been cancelled

Details

b6b0ebb4dc

updateSolveStatus() calls solve() when lastResult_.placements is empty,
but solve() calls updateSolveStatus() at the end. When an assembly has
zero constraints (all joints removed), the solver returns zero
placements, causing infinite recursion until stack overflow (segfault).

Add a static re-entrancy guard so the recursive solve() call is skipped
if updateSolveStatus() is already on the call stack.

forbes merged commit 62f077a267 into main

2026-02-21 15:48:02 +00:00

forbes deleted branch fix/assembly-empty-joints-segfault

2026-02-21 15:48:02 +00:00

forbes referenced this issue from a commit

2026-02-21 15:48:03 +00:00

Merge pull request 'fix(assembly): prevent segfault when all joints are removed' (#310) from fix/assembly-empty-joints-segfault into main

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Reference: kindred/create#310