penpot/docs/component-bug-reports

Component / Variant subsystem — bug reports

Each report below is self-contained and meant to be tackled independently in a fresh agent context. They came out of the audit captured in ../component-subsystem-handoff.md (§14).

Read the handoff doc and the Serena memory critical-info before starting any of them.

#	Title	Category	Confidence	Severity	On hot path?
BUG-01	concat-changes accumulates :undo-changes as nested lazy concat	Stability + Perf	High	Medium (latent crash on large files)	Yes (library sync)
BUG-02	Un-memoized ref-chain walking during variant switch	Perf	Medium	Low–Medium	Yes (variant switch)
BUG-03	compare-children fallback is O(n²) with expensive constant	Perf	Medium	Low–Medium	Yes (sync)
BUG-04	update-attrs-on-switch composite-geometry guard audit	Correctness	Low (audit)	Variable	Yes (swap)
BUG-05	Silent no-op vs. bug ambiguity in direct sync	Diagnosability	Low	Low	Yes (sync)
BUG-06	d/index-of linear scan inside per-child sync callbacks	Perf	High	Medium	Yes (sync)
BUG-07	Inverse sync re-maps the entire change list at every tree node	Perf + Stability	High	Medium	Yes ("Update main")
BUG-08	variant-switch crashes on empty / out-of-range target (plugin-facing)	Correctness	High	High (reproducible crash)	Yes (Plugin API)

Suggested order

1. BUG-08 — reproducible plugin-triggered crash, small guard fix, clear test. Most aligned with the current alotor-fix-plugins-problems branch.
2. BUG-06 — pure perf, mechanical, no behavior change.
3. BUG-01 / BUG-07 — the lazy-concat stability pair (real crash risk on large files; needs care to preserve undo order).
4. BUG-02 / BUG-03 — profile first, then optimize.
5. BUG-04 / BUG-05 — audit / diagnosability, lower urgency.