Write Upgrade

Writing a Webiny Upgrade Script

File Structure

Every upgrade lives in src/upgrades/<version>/ and consists of exactly two files:

src/upgrades/6.2.0/
  Upgrade.ts    # implementation
  index.ts      # feature export (default export)

Use relative imports throughout — ~/ aliases are not reliable here.

Upgrade.ts

Implement Upgrade.Interface — a version property and two methods: canHandle and execute.

canHandle returns true when this upgrade's version falls within the range (currentVersion, targetVersion] — strictly greater than currentVersion and less than or equal to targetVersion.

• currentVersion is the user's installed Webiny version. It acts as a lower bound so that upgrades at or below the user's current version are skipped. The handler advances currentVersion after each successful upgrade step, so when running 6.1.0 → 6.3.0, the 6.2.0 upgrade sees currentVersion=6.1.0 and the 6.3.0 upgrade sees currentVersion=6.2.0.
• targetVersion is the version the user wants to reach. It caps the upper bound so only relevant upgrades run.

Both bounds are required — without currentVersion, older upgrades would re-run on every invocation. The handler also checks upgrade history and skips already-executed upgrades as a second layer of protection. Do not use registry checks — the version does not exist on npm yet when the upgrade is being written.

import { Upgrade as UpgradeAbstraction } from "../../base/Upgrade/index.js";
import { PackageJsonTool } from "../../tool/PackageJsonTool/index.js";
import { WebinyConfigTool } from "../../tool/WebinyConfigTool/index.js";
import { Version } from "../../base/Version/index.js";

class UpgradeImpl implements UpgradeAbstraction.Interface {
    public readonly version = Version.create("6.2.0");

    public constructor(
        private readonly packageJsonTool: PackageJsonTool.Interface,
        private readonly webinyConfigTool: WebinyConfigTool.Interface
    ) {}

    public async canHandle({ targetVersion, currentVersion }: UpgradeAbstraction.Params): Promise<boolean> {
        return this.version.between(currentVersion, targetVersion);
    }

    public async execute(): Promise<void> {
        const packageJson = this.packageJsonTool.loadOrThrow();
        // Version-specific transformations go here.
        this.packageJsonTool.save(packageJson);
    }
}

export const Upgrade = UpgradeAbstraction.createImplementation({
    implementation: UpgradeImpl,
    dependencies: [PackageJsonTool, WebinyConfigTool]
});

Only include WebinyConfigTool in dependencies if the upgrade actually modifies webiny.config.tsx.

index.ts

import { createFeature } from "../../utils/createFeature.js";
import { Upgrade } from "./Upgrade.js";

export default createFeature({
    name: "Upgrade 6.2.0",
    register(container) {
        container.register(Upgrade);
    }
});

Available Dependencies

Declare these in the dependencies array of createImplementation. They are resolved from the DI container automatically.

WebinyConfigFile API

The object returned by WebinyConfigTool.read():

// imports sub-object
file.imports.add(options: ImportOptions): void
file.imports.remove(options: RemoveImportOptions): void

// jsx sub-object
file.jsx.addChild(tag: string, options?: ChildOptions): void
file.jsx.insertBefore(ref: string, tag: string, options?: ChildOptions): void
file.jsx.insertAfter(ref: string, tag: string, options?: ChildOptions): void

// file
file.save(): void

type ImportEntry = string | Record<string, string>;
interface ImportOptions {
    package: string;
    imports: ImportEntry[];        // plain string or { originalName: localAlias }
}

interface RemoveImportOptions {
    package: string;
    imports?: string[];            // omit to remove the entire declaration
}

interface ChildOptions {
    comment?: string;                       // renders as {/* comment */} above the element
    props?: Record<string, string>;         // expression syntax: { passphrase: 'process.env.X || ""' }
    children?: (jsx: Jsx) => void;          // nested children callback
}

jsx.addChild behaviour:

• Not found → inserts after the last JSX fragment child (self-closing if no children, block element if children provided)
• Found, no children callback → logs a warning and skips (never creates duplicates)
• Found, children callback provided → structural merge: recurses into the existing element

jsx.insertBefore(ref, tag, options) / jsx.insertAfter(ref, tag, options) behaviour:

• ref not found → warns and falls back to append at end
• tag already exists → warns and no-ops — no structural merge, even if options.children provided
• Normal path → inserts tag immediately before/after the first occurrence of ref; indent is inferred from ref's column offset
• Available at every nesting level via the Jsx object passed to a children callback

PackageJsonFile API

The object returned by PackageJsonTool.load() or PackageJsonService.load():

// read
file.getDependencies(): Record<string, string>
file.getDevDependencies(): Record<string, string>
file.getPeerDependencies(): Record<string, string>
file.getResolutions(): Record<string, string>
file.getVersion(): string | null

// dependencies
file.getDependency(name: string): string | null
file.setDependency(name: string, version: string | Version): void
file.removeDependency(name: string): void

// devDependencies
file.getDevDependency(name: string): string | null
file.setDevDependency(name: string, version: string | Version): void
file.removeDevDependency(name: string): void

// peerDependencies
file.getPeerDependency(name: string): string | null
file.setPeerDependency(name: string, version: string | Version): void
file.removePeerDependency(name: string): void

// resolutions
file.getResolution(name: string): string | null
file.setResolution(name: string, version: string | Version): void
file.removeResolution(name: string): void

// arbitrary fields
file.get(key: string): unknown
file.set(key: string, value: unknown): void

Testing

Every upgrade needs both a unit test and an integration test.

Unit test (Upgrade.test.ts)

Next to Upgrade.ts. Mocks PackageJsonTool via registerUpgradeDeps. Uses the canonical createMockPackageJsonFile from src/__tests__/utils/. If the upgrade uses WebinyConfigTool, register a mock instance directly in createContainer (not in registerUpgradeDeps). Existing examples: src/upgrades/6.3.0/Upgrade.test.ts.

Integration test (Upgrade.integration.test.ts)

Next to Upgrade.ts. Uses the real UpgradeHandler + UpgradeRunner pipeline against a fixture package.json copied into a tmpdir.

Layout:

src/upgrades/<version>/
├── Upgrade.ts
├── Upgrade.test.ts
├── Upgrade.integration.test.ts
├── __tests__/
│   └── fixtures/
│       └── before/
│           └── package.json         ← hand-written, minimal, self-contained
└── index.ts

Test shape:

import { describe, it, expect } from "vitest";
import path from "node:path";
import { createUpgradeIntegrationHarness } from "../../__tests__/utils/createUpgradeIntegrationHarness.js";

const fixtureDir = path.join(import.meta.dirname, "__tests__", "fixtures", "before");

describe("Upgrade 6.x.0 - integration", () => {
    it("applies its transformations and pins @webiny/* to the target version", async () => {
        const harness = await createUpgradeIntegrationHarness({
            fixtureDir,
            currentVersion: "6.(x-1).0",
            targetVersion: "6.x.0"
        });

        await harness.run();

        const pkg = harness.readPackageJson();
        // assert upgrade-specific transformations
        expect(pkg.dependencies?.["@webiny/cli"]).toBe("6.x.0");
        expect(harness.upgradeHistory.list()).toContainEqual(
            expect.objectContaining({ version: "6.x.0" })
        );
    });
});

Chain test

After shipping a new upgrade, bump targetVersion and extend assertions in src/__tests__/integration/chain.test.ts.

Coverage

Thresholds in vitest.config.ts enforce 100% statements / functions / lines and 98% branches. yarn test:coverage fails if any threshold regresses.

Post-Task Sequence

After every change, run:

yarn && yarn build && yarn adio:check && yarn format:fix && yarn lint:fix && yarn test:coverage

If any step fails, fix the issue and re-run the full chain.

Fix Upgrades

To ship a bugfix for an already-released upgrade (e.g. 6.1.0), create a new upgrade with a pre-release version like 6.1.0-fix.0. History matching is exact on version.raw, so 6.1.0-fix.0 runs even when 6.1.0 is already in history.

Rules

• canHandle must return this.version.between(currentVersion, targetVersion) — this upgrade's hardcoded version must fall in the range
• Do NOT call upWebiny.execute() in an upgrade — the handler pins all @webiny/* packages to the target version after all upgrade steps complete
• Never check the npm registry in canHandle or execute — the version does not exist yet
• Always inject dependencies, never instantiate services directly
• Use relative imports, not ~/
• Windows compatibility: use path.join() for all file paths, never string concatenation or hardcoded slashes