Constructor validation prevents reconstruction of groups with removed members

[johnson86tw]

Problem

The Group constructor validates that no member can be 0n, but the removeMember() method sets removed members to 0n. This creates an inconsistency where a valid group state cannot be reconstructed using the constructor with the members array.

Steps to Reproduce

import { Group } from "@semaphore-protocol/group"

// Create a group and remove a member
const group = new Group([1n, 2n, 3n])
group.removeMember(1)  // Sets members[1] to 0n

// Try to recreate the group from its members
const members = group.members  // [1n, 0n, 3n]
const newGroup = new Group(members)  // ❌ Throws: "Failed to add member: value cannot be 0"

Current Behavior

The constructor throws an error when trying to create a group from a members array that contains 0n values (removed members).

Expected Behavior

The constructor should accept 0n values.

Impact

Users cannot reconstruct a group from its members array if any members have been removed

Related Code

semaphore/packages/group/src/index.ts

Lines 25 to 30 in 1dc597a

	constructor(members: BigNumber[] = []) {
	for (const member of members) {
	if (member === 0n || member === "0") {
	throw new Error("Failed to add member: value cannot be 0")
	}
	}