• Type: Correctness / Data corruption risk
• Severity: High
• Component: Particle checkpoint/plotfile pre-post metadata
• Location:
  • Src/Particle/AMReX_ParticleIO.H:485
  • Src/Particle/AMReX_ParticleContainer.H:1262
  • Src/Particle/AMReX_ParticleContainer.H:1422

Problem

CheckpointPre() computes maxnextid as Long, then stores it as:

maxnextidPrePost = int(maxnextid);

The container member and getter are also int. Particle IDs are 64-bit packed IDs and can exceed 32-bit range.

Impact

• ID truncation in pre/post write path.
• Header can store a wrapped/incorrect next ID.
• Restart may reset ID generator too low, risking duplicate IDs and corrupted particle identity semantics.

Suggested patch

Keep this value in Long end-to-end.

--- a/Src/Particle/AMReX_ParticleContainer.H
+++ b/Src/Particle/AMReX_ParticleContainer.H
@@
-    int GetMaxNextIDPrePost () const { return maxnextidPrePost; }
+    Long GetMaxNextIDPrePost () const { return maxnextidPrePost; }
@@
-    int maxnextidPrePost;
+    Long maxnextidPrePost;

--- a/Src/Particle/AMReX_ParticleIO.H
+++ b/Src/Particle/AMReX_ParticleIO.H
@@
-    maxnextidPrePost  = int(maxnextid);
+    maxnextidPrePost  = maxnextid;

Prepared by Codex