[jipeng6036-del]

With enableArrayMethods(), a recipe that moves an object between lists and then updates it can mutate the original state, or throw when the base is frozen:

produce({todo: [{done: false}], done: []}, draft => {
  const item = draft.todo.pop()
  draft.done.push(item)
  item.done = true
})

Read only the removed element through the existing draft proxy before optimized pop / shift. Use the normal proxy path for splice, preserving removed drafts, native argument coercion and sparse-array behavior. Newly inserted external objects keep their existing undrafted behavior.

splice consequently has the standard proxy cost; pop / shift retain their internal-copy optimization. The documentation makes that tradeoff explicit.

Validation:

• 32 regression cases: original source 10 failures / 22 controls pass; candidate all pass, including frozen inputs, patches/undo, prior draft identity, external values, getters and no-op sharing.
• Windows and Linux: yarn test (4,244 source and 3,693 production tests pass; 8 skips in each), Flow, coverage and all four existing performance scripts passed. The unchanged fork Test workflow also passed on this commit.
• Fresh consumers installed actual local npm pack artifacts: 102 public CJS/ESM checks pass across Windows/Linux; baseline defects reproduce. These are local artifacts, not a registry release.

Reproduction, exact artifacts, independent checks and size/performance limitations. The size tool needed a size-only OpenSSL compatibility option; the original failed measurements are retained separately.

Prepared and validated with Codex.