Council refund script - https://github.com/paritytech/polkadot/issues/4160

council-fix.ts

import { ApiPromise, WsProvider } from "@polkadot/api";
import { BN } from "@polkadot/util";
import axios from "axios";

async function scrapeSubscan(api: ApiPromise) {
	const [from, to] = [3899547, 4876134];
	const DOTS = new BN(10000000000);
	const HUNDRED = new BN(100);
	const REFUND = new BN(new BN(495).mul(DOTS).div(HUNDRED))
	const key = process.env['API'] || "DEFAULT_KEY";
	console.log(`using api key: ${key}`)
	const finalRefunds = [];

	function DOT(amount: BN) {
		return api.createType('Balance', amount).toHuman()
	}

	let page = 0;
	const rows = 10;

	while (true) {
		const data = await axios.post(`https://polkadot.api.subscan.io/api/scan/extrinsics`, {
			"row": rows,
			"page": page,
			"module": "electionsphragmen",
			"call": "remove_voter",
			"signed": "all",
			"block_range": `${from}-${to}`,
			"no_params": true,
			"address": "",
		}, { headers: { "X-API-Key": key } })

		// @ts-ignore
		const txs: any[] = data.data.data.extrinsics;

		if (!txs || txs.length === 0) {
			break
		}
		console.log(`fetched remove_voter ${txs.length} transactions from page ${page}`);

		for (const tx of txs) {
			if (!tx.success) {
				continue
			}
			const who = tx.account_id;

			const block = Number(tx.block_num);
			const hash = await api.rpc.chain.getBlockHash(block);
			const parentHash = (await api.rpc.chain.getHeader(hash)).parentHash;
			// @ts-ignore
			const postReserved: BN = (await api.query.system.account.at(hash, who)).data.reserved

			const parentHashApi = await api.at(parentHash);

			// @ts-ignore
			const preReserved: BN = (await parentHashApi.query.system.account(who)).data.reserved;
			let preDeposit = new BN(0);
			if (parentHashApi.query.electionsPhragmen) {
				// @ts-ignore
				preDeposit = (await parentHashApi.query.electionsPhragmen.voting(who)).deposit
			}  else if (parentHashApi.query.phragmenElection) {
				// @ts-ignore
				preDeposit = (await parentHashApi.query.phragmenElection.voting(who)).deposit
			} else {
				console.log('ERRROR');
				throw "could not get PreDeposit from anywhere"
			}

			if (preDeposit.eq(DOTS.mul(new BN(5)).div(HUNDRED))) {
				console.log(`🚨 ${who} at ${block} // preReserve: ${DOT(preReserved)} postReserved: ${DOT(postReserved)} // preDeposit ${DOT(preDeposit)}`)
				// this person has left whilst the deposit was recorded 5 milli DOTS.
				if (!preReserved.sub(postReserved).abs().eq(preDeposit)) {
					// the pre-post reserve's diff must be exactly our expected preDeposit.
					console.log('\tbut something seems off here...')
					continue
				}
				if (postReserved.lt(REFUND)) {
					console.log(`\t🤷 but this does not have enough reserved balance`);
					continue
				}
				finalRefunds.push(api.createType('AccountId', who).toU8a())
			} else {
				console.log(`😮‍💨 ${who} at ${block}, not issues with PreDeposit of ${DOT(preDeposit)} [reserved: ${DOT(preReserved)} -> ${DOT(postReserved)}]`)
			}

		}
		page += 1
	}

	page = 0;
	while (true) {
		const data = await axios.post(`https://polkadot.api.subscan.io/api/scan/extrinsics`, {
			"row": rows,
			"page": page,
			"module": "electionsphragmen",
			"call": "vote",
			"signed": "all",
			"block_range": `${from}-${to}`,
			"no_params": true,
			"address": "",
		}, { headers: { "X-API-Key": key } })

		// @ts-ignore
		const txs: any[] = data.data.data.extrinsics;

		if (!txs || txs.length === 0) {
			break
		}
		console.log(`fetched vote ${txs.length} transactions from page ${page}, ${txs.filter((t) => !t.success).length} of which are invalid`);

		for (const tx of txs) {
			if (!tx.success) {
				continue
			}
			const who = tx.account_id;

			const block = Number(tx.block_num);
			const hash = await api.rpc.chain.getBlockHash(block);
			const parentHash = (await api.rpc.chain.getHeader(hash)).parentHash;
			// @ts-ignore
			const postReserved: BN = (await api.query.system.account.at(hash, who)).data.reserved

			const parentHashApi = await api.at(parentHash);

			// @ts-ignore
			const preReserved: BN = (await parentHashApi.query.system.account(who)).data.reserved;
			let preDeposit = new BN(0);
			if (parentHashApi.query.electionsPhragmen) {
				// @ts-ignore
				preDeposit = (await parentHashApi.query.electionsPhragmen.voting(who)).deposit
			}  else if (parentHashApi.query.phragmenElection) {
				// @ts-ignore
				preDeposit = (await parentHashApi.query.phragmenElection.voting(who)).deposit
			} else {
				console.log('ERRROR');
				throw "could not get PreDeposit from anywhere"
			}

			if (preDeposit.eq(DOTS.mul(new BN(5)).div(HUNDRED))) {
				console.log(`🚨 ${who} at ${block} // preReserve: ${DOT(preReserved)} postReserved: ${DOT(postReserved)} // preDeposit ${DOT(preDeposit)}`)
				if (postReserved.lt(REFUND)) {
					console.log(`\t🤷 but this does not have enough reserved balance`);
					continue
				}
				finalRefunds.push(api.createType('AccountId', who).toU8a())
				// this person has left whilst the deposit was recorded 5 milli DOTS.
			} else {
				console.log(`😮‍💨 ${who} at ${block}, not issues with PreDeposit of ${DOT(preDeposit)} [reserved: ${DOT(preReserved)} -> ${DOT(postReserved)}]`)
			}
		}
		page += 1
	}

	console.log('✅ Done');
	console.log(finalRefunds);

}

async function main() {
	const provider = new WsProvider("wss://rpc.polkadot.io");
	const api = await ApiPromise.create({ provider });
	console.log(`Connected to node polkadot ${(await api.rpc.system.chain()).toHuman()} [ss58: ${api.registry.chainSS58}]`)

	await scrapeSubscan(api)
}

main().catch(console.error).finally(() => process.exit());