fix(EffectComposer): drop dedupeByLastOccurrence, fixed upstream in r3f 9.7.0

r3f 9.7.0 fixes the reconciler bug this workaround existed for: internal
instance children were drifting out of sync on a keyed reorder (reported
upstream by us, fixed in pmndrs/react-three-fiber#3808). With the fix in
place, group.current.__r3f.children no longer contains a stale duplicate
after React moves a keyed child, so the dedupe step is no longer needed.

Bumped @react-three/fiber to ^9.7.0 and removed dedupeByLastOccurrence,
reading groupInstance.children directly.

Verified empirically: the existing reorder-with-key test passes on 9.7.0
without the workaround, and fails with the exact same symptom as before
(Expected EffectPass with 2 effects) when temporarily downgraded back to
9.6.1 with the workaround still removed - confirming this is the actual
upstream fix taking effect, not a coincidence.

Author: kvvasuu

package.json

@@ -38,7 +38,7 @@
     "@eslint/compat": "^2.1.0",
     "@eslint/eslintrc": "^3.3.6",
     "@eslint/js": "^9.39.5",
-    "@react-three/fiber": "^9.6.1",
+    "@react-three/fiber": "^9.7.0",
     "@types/node": "^26.1.1",
     "@types/react": "^19.2.17",
     "@types/three": "^0.182.0",

src/EffectComposer.tsx

@@ -59,22 +59,6 @@ type ComposerState = {
 const isConvolution = (effect: Effect): boolean =>
   (effect.getAttributes() & EffectAttribute.CONVOLUTION) === EffectAttribute.CONVOLUTION
 
-/**
- * r3f's host config doesn't detach an existing instance from its old slot
- * when React moves it (a key-preserving reorder of siblings) — it just
- * splices/pushes the moved instance into its new slot, leaving a stale
- * duplicate of the same object behind at the old one. Deduping by last
- * occurrence recovers the correct order regardless: the stale copy is
- * always left behind first, the moved one lands later.
- */
-function dedupeByLastOccurrence(children: Instance<Group>['children']): unknown[] {
-  const lastIndex = new Map<unknown, number>()
-  children.forEach((child, index) => lastIndex.set(child.object, index))
-  return Array.from(lastIndex.entries())
-    .sort(([, a], [, b]) => a - b)
-    .map(([object]) => object)
-}
-
 /**
  * Groups a flat, ordered list of Effect/Pass instances into actual composer
  * passes, merging consecutive non-convolution Effects into a single
@@ -192,7 +176,7 @@ export const EffectComposer = /* @__PURE__ */ memo(function EffectComposer({
     const groupInstance = (group.current as Group & { __r3f: Instance<Group> }).__r3f
 
     if (groupInstance) {
-      const nodes = dedupeByLastOccurrence(groupInstance.children).filter(
+      const nodes = groupInstance.children.map((child) => child.object).filter(
         (object): object is Effect | Pass => object instanceof Effect || object instanceof Pass
       )