Carry property, Font and Media Replacement overrides into the collapsed nested EvalCtx so nested layers render beyond the precomp frame instead of falling back to a clipped, flattened image. Key the layer cache on instance overrides to keep distinct collapsed instances isolated.
Every undoable edit keeps the previous project for undo, so the comp it touches
is shared and Arc::make_mut deep-copies it: every layer and every keyframe. An
edit therefore costs time in proportion to the comp's size, and a script that
sets many keyframes in a big comp goes quadratic (a 1,600-layer build with
~100k sampled keys took ~45 minutes).
Comp::layers is now a Layers collection backed by Vec<Arc<Layer>>: copying the
stack copies pointers, and only the layer an edit changes is copied. The API
mirrors Vec<Layer>; serialized form is unchanged (a list of layers).
Comp::layer_mut and the iter_mut().filter/find call sites use find_mut /
iter_mut_where so they copy only the layers they actually change.
- prop.addKey in a 400-layer comp: 1.36 ms -> 0.16 ms per key (flat in comp size)
- the 1,600-layer script build: ~45 min -> 47 s, frames pixel-identical
- regression tests: an edit leaves the other layers shared with undo; layers
round-trip as a plain list
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VkpGcKfWyCudfSsQNiWAaG
bflatastic