react-hooks-js/immutability

Validates against mutating props, state, and other values that [are immutable](https://react.dev/reference/rules/components-and-hooks-must-be-pure#props-and-state-are-immutable)

Validation prompt

Confirm the detector match and collect the required evidence before deciding whether an edit is warranted.

Fires on writes to values the compiler proves are immutable: props, useState values, useReducer state: via property assignment (state.x = v), in-place array methods (push, pop, splice, sort, reverse), or Object.assign(state, ...).

Suppress when: the value is an Immer produce() draft (draft.x = v is legal inside the producer) or some other proxy that intentionally exposes mutable semantics.

Evidence boundary

The diagnostic proves only that the detector’s modeled source pattern matched. It does not prove runtime impact, product intent, rendered failure, or that one remediation is correct.

Establish the environment, repository policy, exceptions, and required rendered or runtime evidence before deciding the occurrence.

Record one outcome:

• Confirmed failure: The required evidence establishes the violation.
• Rejected: A documented exception or false-positive predicate applies.
• Needs evidence: Named evidence can still be collected.
• Unavailable: Required evidence cannot be collected in this run.
• Waived with evidence: An authorized, scoped exception applies to an established failure.
• Observation: The review records an optional tradeoff without claiming a defect.

A waiver records its scope, authority, evidence, and review condition. It is not a pass or false positive.

Default severity is registry metadata. Use the occurrence’s JSON severity after repository configuration when ordering real findings.

Fix prompt

Apply this candidate correction only after the required evidence confirms the risk.

Always create a new container: setItems([...items, newItem]) or setUser({ ...user, name }): spread at every nested level you change. For deep updates prefer useReducer with explicit immutable cases, or wrap producer code in Immer's produce(). React relies on reference identity (Object.is) to detect changes, so mutating the same array/object silently skips re-renders. See https://react.dev/reference/eslint-plugin-react-hooks/lints/immutability

Repository-wide copy prompt

Use this repository-wide prompt only after validating each occurrence. For one occurrence, use the guidance above.