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perf: avoid await import for code that's guaranteed to execute #8086

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a40221b
perf: avoid async loading of import that is always used
Wodann Mar 25, 2026
2ba408b
perf: avoid async loading of deepClone
Wodann Mar 25, 2026
95f0b50
perf: avoid async loading of HardhatEthersSigner
Wodann Mar 25, 2026
242cea9
fix: linter
Wodann Mar 26, 2026
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9 changes: 3 additions & 6 deletions v-next/hardhat-ethers/src/internal/hardhat-helpers/hardhat-helpers.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,6 @@ import type {
Libraries,
} from "../../types.js";
import type { HardhatEthersProvider } from "../hardhat-ethers-provider/hardhat-ethers-provider.js";
import type { HardhatEthersSigner } from "../signers/signers.js";
import type { ethers as EthersT } from "ethers";
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Copilot AI Mar 25, 2026

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Switching from a dynamic import to a static import here means the signer implementation (and its transitive deps like ethers) will be loaded as soon as this module is evaluated, even in flows that never call getSigner/getSigners. If the goal is to remove per-call await import(...) overhead but keep lazy loading, consider caching the imported module/class the first time getSigner is called (lazy + cached) rather than importing it unconditionally at top-level.

Copilot uses AI. Check for mistakes.
import type {
Abi,
Expand All @@ -19,6 +18,8 @@ import {
HardhatError,
} from "@nomicfoundation/hardhat-errors";

import { HardhatEthersSigner } from "../signers/signers.js";

interface Link {
sourceName: string;
libraryName: string;
Expand Down Expand Up @@ -68,11 +69,7 @@ export class HardhatHelpers {
}

public async getSigner(address: string): Promise<HardhatEthersSigner> {
const { HardhatEthersSigner: SignerWithAddressImpl } = await import(
"../signers/signers.js"
);

const signerWithAddress = await SignerWithAddressImpl.create(
const signerWithAddress = await HardhatEthersSigner.create(
this.#provider,
this.#networkName,
this.#networkConfig,
Expand Down
11 changes: 3 additions & 8 deletions v-next/hardhat-utils/src/internal/lang.ts
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@@ -1,15 +1,10 @@
import type rfdcT from "rfdc";
import rfdc from "rfdc";

import { isObject } from "../lang.js";

let clone: ReturnType<typeof rfdcT> | null = null;
export async function getDeepCloneFunction(): Promise<<T>(input: T) => T> {
const { default: rfdc } = await import("rfdc");

if (clone === null) {
clone = rfdc();
}
const clone = rfdc();

export function getDeepCloneFunction(): <T>(input: T) => T {
return clone;
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Copilot AI Mar 25, 2026

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getDeepCloneFunction now eagerly imports rfdc and initializes clone at module load (const clone = rfdc()). Because @nomicfoundation/hardhat-utils/lang is imported widely for unrelated helpers (e.g. isObject, sleep), this change makes every consumer pay the rfdc import/init cost even when deepClone is never called, which can regress startup performance and changes when failures would surface (module-load vs first-call).

Consider restoring lazy initialization while keeping deepClone synchronous, e.g. cache clone but only require("rfdc")/initialize it inside getDeepCloneFunction (using createRequire in ESM), or otherwise ensure this eager load is actually on a guaranteed-hot path.

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}

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6 changes: 2 additions & 4 deletions v-next/hardhat-utils/src/lang.ts
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Expand Up @@ -10,10 +10,8 @@ import {
* @param value The value to clone.
* @returns The deep clone of the provided value.
*/
export async function deepClone<T>(value: T): Promise<T> {
const _deepClone = await getDeepCloneFunction();

return _deepClone<T>(value);
export function deepClone<T>(value: T): T {
return getDeepCloneFunction()<T>(value);
}
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Copilot AI Mar 25, 2026

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Changing deepClone from async (returning Promise<T>) to a synchronous function (returning T) is a breaking public API change for @nomicfoundation/hardhat-utils/lang. Any external consumers using promise chaining (e.g. deepClone(x).then(...)) or typed as Promise will break.

If the sync behavior is required for perf, consider introducing a new sync API (and keeping the existing async deepClone as a thin wrapper for backwards compatibility), or ensure this is released with an appropriate major-version bump and explicit migration notes.

Copilot uses AI. Check for mistakes.

/**
Expand Down
24 changes: 12 additions & 12 deletions v-next/hardhat-utils/test/lang.ts
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Expand Up @@ -17,7 +17,7 @@ describe("lang", () => {
describe("deepClone", () => {
it("Should clone an object", async () => {
const obj = { a: 1, b: 2, c: { d: 3 } };
const clonedObj = await deepClone(obj);
const clonedObj = deepClone(obj);

assert.deepEqual(clonedObj, obj);
assert.notEqual(clonedObj, obj);
Expand All @@ -27,7 +27,7 @@ describe("lang", () => {

it("Should clone an array", async () => {
const arr = [1, 2, [3]];
const clonedArr = await deepClone(arr);
const clonedArr = deepClone(arr);

assert.deepEqual(clonedArr, arr);
assert.notEqual(clonedArr, arr);
Expand All @@ -37,47 +37,47 @@ describe("lang", () => {

it("Should clone a string", async () => {
const str = "hello";
const clonedStr = await deepClone(str);
const clonedStr = deepClone(str);

assert.equal(clonedStr, str);
expectTypeOf(clonedStr).toBeString();
});

it("Should clone a number", async () => {
const num = 42;
const clonedNum = await deepClone(num);
const clonedNum = deepClone(num);

assert.equal(clonedNum, num);
expectTypeOf(clonedNum).toBeNumber();
});

it("Should clone null", async () => {
const n = null;
const clonedN = await deepClone(n);
const clonedN = deepClone(n);

assert.equal(clonedN, n);
expectTypeOf(clonedN).toBeNull();
});

it("Should clone undefined", async () => {
const u = undefined;
const clonedU = await deepClone(u);
const clonedU = deepClone(u);

assert.equal(clonedU, u);
expectTypeOf(clonedU).toBeUndefined();
});

it("Should reference a function", async () => {
const fn = () => {};
const clonedFn = await deepClone(fn);
const clonedFn = deepClone(fn);

assert.equal(clonedFn, fn);
expectTypeOf(clonedFn).toEqualTypeOf<typeof fn>();
});

it("Should clone a Date", async () => {
const date = new Date();
const clonedDate = await deepClone(date);
const clonedDate = deepClone(date);

assert.deepEqual(clonedDate, date);
assert.notEqual(clonedDate, date);
Expand All @@ -89,7 +89,7 @@ describe("lang", () => {
["a", 1],
["b", 2],
]);
const clonedMap = await deepClone(map);
const clonedMap = deepClone(map);

assert.deepEqual(clonedMap, map);
assert.notEqual(clonedMap, map);
Expand All @@ -98,7 +98,7 @@ describe("lang", () => {

it("Should clone a Set", async () => {
const set = new Set([1, 2]);
const clonedSet = await deepClone(set);
const clonedSet = deepClone(set);

assert.deepEqual(clonedSet, set);
assert.notEqual(clonedSet, set);
Expand All @@ -107,7 +107,7 @@ describe("lang", () => {

it("Should clone a Buffer", async () => {
const buffer = Buffer.from("test");
const clonedBuffer = await deepClone(buffer);
const clonedBuffer = deepClone(buffer);

const expected: { [key: number]: number } = {};
for (let i = 0; i < buffer.length; i++) {
Expand All @@ -124,7 +124,7 @@ describe("lang", () => {
return arguments;
}
const args = testFunc(1, "2", false);
const clonedArgs = await deepClone(args);
const clonedArgs = deepClone(args);

assert.deepEqual(clonedArgs, { "0": 1, "1": "2", "2": false });
expectTypeOf(clonedArgs).toHaveProperty("0").toBeNumber();
Expand Down
2 changes: 1 addition & 1 deletion v-next/hardhat/src/internal/builtin-plugins/network-manager/config-resolution.ts
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Expand Up @@ -224,7 +224,7 @@ export function resolveCoinbase(
export async function resolveChainDescriptors(
chainDescriptors: ChainDescriptorsUserConfig | undefined,
): Promise<ChainDescriptorsConfig> {
const resolvedChainDescriptors: ChainDescriptorsConfig = await deepClone(
const resolvedChainDescriptors: ChainDescriptorsConfig = deepClone(
DEFAULT_CHAIN_DESCRIPTORS,
);

Expand Down
5 changes: 1 addition & 4 deletions v-next/hardhat/src/internal/builtin-plugins/network-manager/hook-handlers/network.ts
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Expand Up @@ -12,6 +12,7 @@ import type { RequestHandler } from "../request-handlers/types.js";
import { AsyncMutex } from "@nomicfoundation/hardhat-utils/synchronization";

import { isJsonRpcResponse } from "../json-rpc.js";
import { createHandlersArray } from "../request-handlers/handlers-array.js";

export default async (): Promise<Partial<NetworkHooks>> => {
// This map is essential for managing multiple network connections in Hardhat V3.
Expand All @@ -37,10 +38,6 @@ export default async (): Promise<Partial<NetworkHooks>> => {
nextJsonRpcRequest: JsonRpcRequest,
) => Promise<JsonRpcResponse>,
) {
const { createHandlersArray } = await import(
"../request-handlers/handlers-array.js"
);

const requestHandlers = await initializationMutex.exclusiveRun(
async () => {
let handlersPerConnection =
Expand Down
2 changes: 1 addition & 1 deletion v-next/hardhat/src/internal/builtin-plugins/solidity/build-system/compilation-job.ts
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Expand Up @@ -130,7 +130,7 @@ export class CompilationJobImplementation implements CompilationJob {
// from other files (e.g. new Foo()), and it won't output its bytecode if
// it's not asked for. This would prevent EDR from doing any runtime
// analysis.
const outputSelection = await deepClone(settings.outputSelection ?? {});
const outputSelection = deepClone(settings.outputSelection ?? {});
outputSelection["*"] ??= {};
outputSelection["*"][""] ??= [];
outputSelection["*"]["*"] ??= [];
Expand Down
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