SITES-40700: fix linting/React by AmyJZhao · Pull Request #112 · adobe/uix-sdk

AmyJZhao · 2026-02-20T10:32:30Z

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

I have signed the Adobe Open Source CLA.
My code follows the code style of this project.
My change requires a change to the documentation.
I have updated the documentation accordingly.
I have read the CONTRIBUTING document.
I have added tests to cover my changes.
All new and existing tests passed.

Copilot

Pull request overview

This PR modernizes linting across the monorepo (moving to ESLint v9 flat config) and applies a wide set of formatting/type-import fixes, with a few refactors in React hooks/components to satisfy stricter lint rules.

Changes:

Introduces shared ESLint flat-config (eslint.base.mjs) and per-package eslint.config.mjs, plus workspace lint scripts.
Applies repo-wide lint-driven edits (type-only imports, trailing commas, object key ordering, arrow-function conversions, etc.).
Refactors parts of uix-host-react hooks/components to address React hook dependency and lint constraints.

Reviewed changes

Copilot reviewed 70 out of 73 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/uix-host/src/utils/comparePackagesVersions.ts	Formatting changes to satisfy lint rules (expanded `if` blocks).
packages/uix-host/src/utils/compareExtensions.ts	Type-only imports + stable string sorting with `localeCompare`.
packages/uix-host/src/port.ts	Lint/format updates; minor refactors (regex exec, arrow typeguards, parameter commas).
packages/uix-host/src/port.test.ts	Lint/format updates and import reordering for mocked `connectIframe`.
packages/uix-host/src/metrics.ts	Lint cleanup and minor refactors in metrics wrapper + runtime polling formatting.
packages/uix-host/src/host.ts	Type-only imports and formatting; minor statement/arg ordering adjustments.
packages/uix-host/src/extensions-provider/mute.ts	Type-only import + trailing comma to satisfy lint rules.
packages/uix-host/src/extensions-provider/extension-registry.ts	Type-only imports + formatting; minor lint suppressions.
packages/uix-host/src/extensions-provider/extension-registry.test.ts	Test formatting changes and lint suppression for `require`.
packages/uix-host/src/extensions-provider/composition.ts	Type-only imports + simplified arrow return.
packages/uix-host/src/dom-utils/iframe-normalizers.ts	Type-only imports split + formatting adjustments.
packages/uix-host/src/dom-utils/iframe-normalizers.test.ts	Formatting fixes (trailing commas, blank lines).
packages/uix-host/src/dom-utils/attribute-normalizers.ts	Minor formatting (padding lines).
packages/uix-host/src/dom-utils/attribute-normalizers.test.ts	Import reordering + formatting.
packages/uix-host/src/debug-host.ts	Type-only imports split + formatting updates.
packages/uix-host/package.json	Adds `lint` script for package-local eslint runs.
packages/uix-host/eslint.config.mjs	Adds package ESLint flat-config entrypoint.
packages/uix-host-react/src/hooks/useHost.ts	Converts to `export const` + type-only import cleanup.
packages/uix-host-react/src/hooks/useExtensions.ts	Refactors memo/deps handling, subscriptions, and unload handling to satisfy hooks lint.
packages/uix-host-react/src/hooks/useExtensions.test.tsx	Import cleanup and formatting updates for lint.
packages/uix-host-react/src/hooks/useExtensionListFetched.ts	Converts to `export const` + type-only import cleanup.
packages/uix-host-react/src/extension-context.ts	Type-only import cleanup + formatting.
packages/uix-host-react/src/components/GuestUIFrame.tsx	Refactors connection/resizing effects; removes default export; adds memo/callback refs.
packages/uix-host-react/src/components/ExtensibleWrapper/UrlExtensionProvider.ts	Type-only imports + functional style conversions; formatting updates.
packages/uix-host-react/src/components/ExtensibleWrapper/UrlExtensionProvider.test.ts	Test updates (https URLs, formatting, import changes).
packages/uix-host-react/src/components/ExtensibleWrapper/ExtensionManagerProvider.ts	Type-only imports + functional style conversions; formatting updates.
packages/uix-host-react/src/components/ExtensibleWrapper/ExtensionManagerProvider.test.ts	Test restructuring/formatting + global fetch mocking adjustments.
packages/uix-host-react/src/components/ExtensibleWrapper/ExtensibleWrapper.tsx	Type-only imports + formatting; adjusts `scope` typing to `Record<string,string>`.
packages/uix-host-react/src/components/ExtensibleComponentBoundary.tsx	Type-only import cleanup + minor component formatting; react-refresh lint suppression.
packages/uix-host-react/src/components/Extensible.tsx	Refactors helper + effects/deps to satisfy hooks lint; removes default export.
packages/uix-host-react/src/components/Extensible.test.tsx	Formatting + lint suppressions (max-lines-per-function) and minor mock reshaping.
packages/uix-host-react/package.json	Adds `lint` script (with `--fix`).
packages/uix-host-react/eslint.config.mjs	Adds React-enabled package ESLint flat-config entrypoint.
packages/uix-guest/src/index.ts	Import ordering/type-only adjustments + formatting.
packages/uix-guest/src/guest.ts	Formatting + changes around timeouts and postMessage payload ordering.
packages/uix-guest/src/guest-ui.ts	Import splitting (type vs value) + formatting + `declare` ordering.
packages/uix-guest/src/guest-server.ts	Import ordering/type-only tweaks.
packages/uix-guest/src/debug-guest.ts	Type-only import split + formatting.
packages/uix-guest/package.json	Adds `lint` script for package-local eslint runs.
packages/uix-guest/eslint.config.mjs	Adds package ESLint flat-config entrypoint.
packages/uix-core/src/value-assertions.ts	Formatting + trailing commas.
packages/uix-core/src/types.ts	Formatting + trailing commas + generic formatting.
packages/uix-core/src/tunnel/tunnel.ts	Refactors cleanup placement + adds lint suppressions (random, ignored exceptions).
packages/uix-core/src/tunnel/tunnel.test.ts	Formatting + minor data object key ordering.
packages/uix-core/src/tunnel/tunnel-messenger.ts	Safer `hasOwnProperty` usage + type-only imports split + formatting.
packages/uix-core/src/tunnel/tunnel-messenger.test.ts	Formatting + trailing commas.
packages/uix-core/src/rpc/call-sender.ts	Formatting + adds `max-params` suppression; minor ordering changes.
packages/uix-core/src/rpc/call-sender.test.ts	Import cleanup + formatting; avoids deprecated matcher style warnings.
packages/uix-core/src/rpc/call-receiver.ts	Formatting + argument ordering in response tickets.
packages/uix-core/src/rpc/call-receiver.test.ts	Import cleanup + formatting.
packages/uix-core/src/remote-subject.ts	Import order/type-only adjustments + formatting.
packages/uix-core/src/promises/timed.ts	Formatting + trailing commas.
packages/uix-core/src/promises/promise-wrappers.test.ts	Formatting + avoids deprecated matcher style warnings.
packages/uix-core/src/object-walker.ts	Type cleanup and formatting; refines function type constraints.
packages/uix-core/src/object-simulator.ts	Refactors receiver/sender creation; adjusts binding/caching logic; formatting/lint suppressions.
packages/uix-core/src/object-simulator.test.ts	Snapshot/test updates due to simulator changes + formatting.
packages/uix-core/src/namespace-proxy.ts	Type-only import + formatting + minor key ordering.
packages/uix-core/src/message-wrapper.ts	Formatting + trailing commas.
packages/uix-core/src/logging-formatters.ts	Adds explicit ignored-exception suppression; formatting.
packages/uix-core/src/emitter.ts	Switches to type-only import + formatting + trailing commas.
packages/uix-core/src/debuglog.ts	Formatting and some property ordering changes; minor refactors.
packages/uix-core/src/debug-emitter.ts	Type-only imports split + formatting and payload ordering change.
packages/uix-core/src/cross-realm-object.ts	Formatting + explicit function casting; trailing commas.
packages/uix-core/src/mocks/mock-finalization-registry.ts	Adds `jest` global comment + lint suppression for static mock.
packages/uix-core/src/helpers/jest.messagechannel.cjs	Adds eslint-disable header for CJS require + node globals.
packages/uix-core/package.json	Adds `lint` script for package-local eslint runs.
packages/uix-core/eslint.config.mjs	Adds package ESLint flat-config entrypoint.
package.json	Adds workspace lint runner + upgrades eslint/prettier toolchain deps to support flat config.
eslint.base.mjs	New shared ESLint flat configuration factory used by packages.
e2e/all-versions/host-app/package-lock.json	Updates resolved registry URLs for e2e lockfile dependencies.
e2e/all-versions/guest-app/package-lock.json	Updates resolved registry URLs for e2e lockfile dependencies.
.eslintrc.cjs	Removes legacy ESLint config in favor of flat config.

Files not reviewed (2)

e2e/all-versions/guest-app/package-lock.json: Language not supported
e2e/all-versions/host-app/package-lock.json: Language not supported

Comments suppressed due to low confidence (2)

packages/uix-guest/src/guest.ts:263

invokeAwaiter() sets a timeout whose callback returns Promise.reject(...), but that rejection is not wired to the returned promise (and can become an unhandled rejection when the timer fires). As written, the timeout never rejects the operation. Implement this as a real timeout (e.g., Promise.race between invokeChecker(...) and a promise that rejects in the timer, with proper clearTimeout in finally), or remove this timer if timeoutPromise already enforces the desired limit.
packages/uix-host/src/extensions-provider/extension-registry.ts:149
extensionRegistryExtensionsProvider() has an unreachable return Promise.resolve({}); after already returning the fetchExtensionsFromRegistry(...).then(...) chain. This is dead code and can be removed to avoid confusion (and potential lint warnings about unreachable code).

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Copilot · 2026-03-12T06:58:34Z

packages/uix-host-react/src/hooks/useExtensions.ts

+  const depsKey = JSON.stringify(deps);
  const {
-    requires,
    provides,
+    requires,
    updateOn = "each",
-  } = useMemo(() => configFactory(host), baseDeps);
-
+  } = useMemo(
+    () =>
+      host
+        ? configFactory(host)
+        : ({} as UseExtensionsConfig<Incoming, Outgoing>),
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+    [host, depsKey],
+  );


depsKey is derived via JSON.stringify(deps), which can throw on circular values and also collapses non-serializable deps (e.g., functions become null in arrays). That can cause the hook to stop re-running configFactory when deps actually change, or crash at runtime for certain deps. Prefer using the deps array directly in the dependency list (and require callers to pass stable deps), or compute a safe/stable key that won't throw (e.g., join of primitives) and document the constraint.

Copilot · 2026-03-12T06:58:35Z

packages/uix-core/src/object-simulator.ts

      );
+
      this.subject.onOutOfScope(fnTicket, cleanup);
      this.receiverTicketCache.set(boundFunction, fnTicket);


makeReceiver() looks up receiverTicketCache using the original fn, but stores the ticket using boundFunction as the key. When parent is provided, subsequent visits will call get(fn) again (miss) and create a new ticket each time, which breaks stability/caching of function IDs and can create multiple receivers for the same method. Either always cache by the original fn, or if binding is required, compute the cache key consistently (e.g., look up/store using the same boundFunction value).

Suggested change

this.receiverTicketCache.set(boundFunction, fnTicket);

this.receiverTicketCache.set(fn, fnTicket);

Copilot

Pull request overview

Copilot reviewed 74 out of 77 changed files in this pull request and generated 5 comments.

Files not reviewed (2)

e2e/all-versions/guest-app/package-lock.json: Language not supported
e2e/all-versions/host-app/package-lock.json: Language not supported

Comments suppressed due to low confidence (1)

packages/uix-host-react/src/hooks/useExtensions.ts:127

boundryExtensionPointsAsString is rebuilt with .map(...) on every render, so it gets a new array identity each time. Because getExtensions depends on it, the callback (and the subscribing effect) will also churn/resubscribe even when extensionPoints didn't change. Memoize the mapped array (e.g. useMemo keyed by extensionPoints) to keep dependencies stable.

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packages/uix-guest/src/guest.ts

+    const final = setTimeout(
+      () => Promise.reject(`${address} doesn't exist`),
+      20000,
+    );
    const res = await this.invokeChecker(invoker, address);
+
    return new Promise((resolve) => {
      clearTimeout(final);
      return resolve(res);
    }).catch((e) => {
      clearTimeout(final);
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-return
      return e;
    });


packages/uix-guest/src/guest.test.ts

+  it("BUG: setTimeout callback returns an unhandled rejected Promise instead of rejecting the returned promise", async () => {
+    // Intercept setTimeout to capture the 20s timeout callback without
+    // triggering a real timer (and without jest fake timers, which prevent
+    // Promise microtasks from settling in this test environment).
+    const capturedCallbacks: Array<() => unknown> = [];
+
+    jest.spyOn(global, "setTimeout").mockImplementation(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      (cb: any, ms?: number) => {
+        if (ms === 20000) {
+          capturedCallbacks.push(cb);
+
+          return 0 as unknown as ReturnType<typeof setTimeout>;
+        }
+
+        return 0 as unknown as ReturnType<typeof setTimeout>;
+      },
+    );
+
+    const guest = new Guest({ id: "test-guest" });
+
+    // invokeChecker never resolves — simulates the host method not existing
+    jest
+      .spyOn(guest as unknown as GuestPrivate, "invokeChecker")
+      .mockReturnValue(
+        new Promise(() => {
+          /* noop */
+        }),
+      );
+
+    let isSettled = false;
+
+    (guest as unknown as GuestPrivate)
+      .invokeAwaiter(jest.fn(), testAddress)
+      .then(
+        () => {
+          isSettled = true;
+        },
+        () => {
+          isSettled = true;
+        },
+      );
+
+    await Promise.resolve(); // flush initial microtasks
+
+    expect(capturedCallbacks).toHaveLength(1);
+
+    // Fire the 20-second timeout callback manually
+    const callbackResult = capturedCallbacks[0]();
+
+    // BUG (1): The callback returns a rejected Promise — this is an unhandled
+    // rejection. The correct fix would be to reject the invokeAwaiter promise
+    // via a mechanism that's connected to the outer async function (e.g.
+    // Promise.race or a reject handle captured from the outer promise).
+    expect(callbackResult).toBeInstanceOf(Promise);
+    // Handle the rejection here so it doesn't become an unhandled rejection
+    await expect(callbackResult as Promise<unknown>).rejects.toMatch(
+      /doesn't exist/,
+    );
+
+    await Promise.resolve(); // flush remaining microtasks
+
+    // BUG (2): The awaiterPromise is still pending — the setTimeout callback
+    // rejection was never connected to it, so the caller will wait forever.
+    expect(isSettled).toBe(false);
+  });


packages/uix-host-react/src/hooks/useExtensions.ts

+  const { host } = useHost();
  const [hostError, setHostError] = useState<Error>();
  const extensionPoints = useContext(ExtensibleComponentBoundaryContext);


packages/uix-host-react/src/hooks/useExtensions.ts

+  const depsKey = JSON.stringify(deps);
  const {
-    requires,
    provides,
+    requires,
    updateOn = "each",
-  } = useMemo(() => configFactory(host), baseDeps);
-
+  } = useMemo(
+    () =>
+      host
+        ? configFactory(host)
+        : ({} as UseExtensionsConfig<Incoming, Outgoing>),
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+    [host, depsKey],
+  );


packages/uix-host-react/src/components/GuestUIFrame.tsx

+      if (connection) {
+        connection.tunnel.destroy();
+      }
+    };
+  }, [guest, host, methods, privateMethods]);


Copilot

Pull request overview

Copilot reviewed 74 out of 77 changed files in this pull request and generated 3 comments.

Files not reviewed (2)

e2e/all-versions/guest-app/package-lock.json: Language not supported
e2e/all-versions/host-app/package-lock.json: Language not supported

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packages/uix-guest/src/guest.ts

+    const final = setTimeout(
+      () => Promise.reject(`${address} doesn't exist`),
+      20000,
+    );
    const res = await this.invokeChecker(invoker, address);
+
    return new Promise((resolve) => {
      clearTimeout(final);
      return resolve(res);
    }).catch((e) => {
      clearTimeout(final);
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-return
      return e;
    });
  }


packages/uix-guest/src/guest.test.ts

+  it("BUG: setTimeout callback returns an unhandled rejected Promise instead of rejecting the returned promise", async () => {
+    // Intercept setTimeout to capture the 20s timeout callback without
+    // triggering a real timer (and without jest fake timers, which prevent
+    // Promise microtasks from settling in this test environment).
+    const capturedCallbacks: Array<() => unknown> = [];
+
+    jest.spyOn(global, "setTimeout").mockImplementation(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      (cb: any, ms?: number) => {
+        if (ms === 20000) {
+          capturedCallbacks.push(cb);
+
+          return 0 as unknown as ReturnType<typeof setTimeout>;
+        }
+
+        return 0 as unknown as ReturnType<typeof setTimeout>;
+      },
+    );
+
+    const guest = new Guest({ id: "test-guest" });
+
+    // invokeChecker never resolves — simulates the host method not existing
+    jest
+      .spyOn(guest as unknown as GuestPrivate, "invokeChecker")
+      .mockReturnValue(
+        new Promise(() => {
+          /* noop */
+        }),
+      );
+
+    let isSettled = false;
+
+    (guest as unknown as GuestPrivate)
+      .invokeAwaiter(jest.fn(), testAddress)
+      .then(
+        () => {
+          isSettled = true;
+        },
+        () => {
+          isSettled = true;
+        },
+      );
+
+    await Promise.resolve(); // flush initial microtasks
+
+    expect(capturedCallbacks).toHaveLength(1);
+
+    // Fire the 20-second timeout callback manually
+    const callbackResult = capturedCallbacks[0]();
+
+    // BUG (1): The callback returns a rejected Promise — this is an unhandled
+    // rejection. The correct fix would be to reject the invokeAwaiter promise
+    // via a mechanism that's connected to the outer async function (e.g.
+    // Promise.race or a reject handle captured from the outer promise).
+    expect(callbackResult).toBeInstanceOf(Promise);
+    // Handle the rejection here so it doesn't become an unhandled rejection
+    await expect(callbackResult as Promise<unknown>).rejects.toMatch(
+      /doesn't exist/,
+    );
+
+    await Promise.resolve(); // flush remaining microtasks
+
+    // BUG (2): The awaiterPromise is still pending — the setTimeout callback
+    // rejection was never connected to it, so the caller will wait forever.
+    expect(isSettled).toBe(false);
+  });


packages/uix-host/src/metrics.ts

  if ("exc-module-runtime" in window) {
    metrics.mertricsInstance = createMetricsInstance();
    return;


- Revert useEffect deps in Extensible.tsx back to [debug, hostName, runtimeContainer, extensions] to avoid spurious re-runs caused by host state feedback and unintended guestOptions reactivity; suppress the exhaustive-deps lint warning with eslint-disable comment - Revert scope type in ExtensibleWrapper.tsx from Record<string, string> back to Record<string, any> to preserve the public TypeScript contract; suppress no-explicit-any with eslint-disable comment - Restore unload: mockUnload to MockedHost.mockImplementation in Extensible.test.tsx — accidentally dropped by alphabetical key reordering during the linting pass, causing 4 tests to silently fail Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Copilot

Pull request overview

Copilot reviewed 74 out of 77 changed files in this pull request and generated 11 comments.

Files not reviewed (2)

e2e/all-versions/guest-app/package-lock.json: Language not supported
e2e/all-versions/host-app/package-lock.json: Language not supported

Comments suppressed due to low confidence (3)

packages/uix-host-react/src/components/GuestUIFrame.tsx:207

This file previously had a default export (now removed). If any downstream code relies on deep-importing GuestUIFrame as a default export, this is a breaking change. Consider keeping a default export for backwards compatibility (or explicitly documenting the breaking change) while still exporting the named GuestUIFrame.
packages/uix-host-react/src/components/Extensible.tsx:257
This component file previously provided a default export (now removed). If consumers deep-import Extensible as a default export, this becomes a breaking change. Consider retaining a default export for compatibility (or clearly documenting the breaking change) while keeping the named export.
packages/uix-host-react/src/components/ExtensibleWrapper/ExtensibleWrapper.tsx:154
This file previously exported ExtensibleWrapper as a default export (now removed). If any consumers deep-import it via default export, this is a breaking change. Consider keeping a default export for backwards compatibility (or documenting the breaking change) while still exporting the named ExtensibleWrapper.

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packages/uix-guest/src/guest.ts

  private async invokeAwaiter(
    invoker: RemoteMethodInvoker<unknown>,
    address: HostMethodAddress<unknown[]>,
  ): Promise<any> {
-    const final = setTimeout(() => {
-      return new Promise((resolve, reject) =>
-        reject(`${address} doesn't exist`),
-      );
-    }, 20000);
+    const final = setTimeout(
+      () => Promise.reject(`${address} doesn't exist`),
+      20000,
+    );
    const res = await this.invokeChecker(invoker, address);
+
    return new Promise((resolve) => {
      clearTimeout(final);
      return resolve(res);
    }).catch((e) => {
      clearTimeout(final);
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-return
      return e;
    });


packages/uix-guest/src/guest.test.ts

+  it("BUG: setTimeout callback returns an unhandled rejected Promise instead of rejecting the returned promise", async () => {
+    // Intercept setTimeout to capture the 20s timeout callback without
+    // triggering a real timer (and without jest fake timers, which prevent
+    // Promise microtasks from settling in this test environment).
+    const capturedCallbacks: Array<() => unknown> = [];
+
+    jest.spyOn(global, "setTimeout").mockImplementation(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      (cb: any, ms?: number) => {
+        if (ms === 20000) {
+          capturedCallbacks.push(cb);
+
+          return 0 as unknown as ReturnType<typeof setTimeout>;
+        }
+
+        return 0 as unknown as ReturnType<typeof setTimeout>;
+      },
+    );
+
+    const guest = new Guest({ id: "test-guest" });
+
+    // invokeChecker never resolves — simulates the host method not existing
+    jest
+      .spyOn(guest as unknown as GuestPrivate, "invokeChecker")
+      .mockReturnValue(
+        new Promise(() => {
+          /* noop */
+        }),
+      );
+
+    let isSettled = false;
+
+    (guest as unknown as GuestPrivate)
+      .invokeAwaiter(jest.fn(), testAddress)
+      .then(
+        () => {
+          isSettled = true;
+        },
+        () => {
+          isSettled = true;
+        },
+      );
+
+    await Promise.resolve(); // flush initial microtasks
+
+    expect(capturedCallbacks).toHaveLength(1);
+
+    // Fire the 20-second timeout callback manually
+    const callbackResult = capturedCallbacks[0]();
+
+    // BUG (1): The callback returns a rejected Promise — this is an unhandled
+    // rejection. The correct fix would be to reject the invokeAwaiter promise
+    // via a mechanism that's connected to the outer async function (e.g.
+    // Promise.race or a reject handle captured from the outer promise).
+    expect(callbackResult).toBeInstanceOf(Promise);
+    // Handle the rejection here so it doesn't become an unhandled rejection
+    await expect(callbackResult as Promise<unknown>).rejects.toMatch(
+      /doesn't exist/,
+    );
+
+    await Promise.resolve(); // flush remaining microtasks
+
+    // BUG (2): The awaiterPromise is still pending — the setTimeout callback
+    // rejection was never connected to it, so the caller will wait forever.
+    expect(isSettled).toBe(false);
+  });


package.json

    "lint": "run-p lint:*",
+    "lint:eslint": "npm run --workspaces --if-present lint",
    "lint:format": "prettier --check packages/*/src",
    "lint:pkg": "fixpack --dryRun; npx --ws -p fixpack -c 'fixpack --dryRun --quiet'",


package.json

    "del-cli": "^5.0.0",
-    "eslint": "^8.21.0",
+    "eslint": "9.31.0",
+    "eslint-config-prettier": "^10.1.8",
+    "eslint-import-resolver-typescript": "^4.4.4",


package.json

    "lint": "run-p lint:*",
+    "lint:eslint": "npm run --workspaces --if-present lint",


packages/uix-core/package.json

  "scripts": {
    "build": "tsup",
    "build:esm": "tsup --format esm,cjs",
+    "lint": "eslint src --fix",


packages/uix-guest/package.json

  "scripts": {
    "build": "tsup",
    "build:esm": "tsup --format esm,cjs,iife",
+    "lint": "eslint src --fix",
    "watch": "tsup --watch --silent"


packages/uix-host-react/package.json

  "scripts": {
    "build": "tsup",
    "build:esm": "tsup --format esm,cjs",
+    "lint": "eslint src --fix",
    "test": "NODE_ENV=test jest",


packages/uix-host/src/port.ts

  public get metadata(): GuestMetadata {
    if (this.isReady() && this.guestServer) {
      const server = this.guestServer.getRemoteApi();
+
      return server && server.metadata;
    }
  }


packages/uix-host/src/extensions-provider/extension-registry.ts

    }, {}),
  );

  return Promise.resolve({});
-}
+};


…config This branch upgrades ESLint v8 → v9.31.0 and introduces a flat config setup (eslint.base.mjs shared factory + per-package eslint.config.mjs), wires ESLint into npm run lint via lint:eslint, and restores uix-guest as a Jest project in jest.config.ts. Update copilot-instructions.md: - Stack line: ESLint 9 flat config, Prettier 3 - Step 5 in command sequence: lint now includes ESLint --fix - npm test description: lint phase now includes ESLint - ESLint section: rewrite for flat config; document key rules that cause failures (import order, key order, function length, etc.) - Testing config: 4 Jest projects (uix-guest restored) - Key config table: replace .eslintrc.cjs with eslint.base.mjs Update CLAUDE.md: - Clarify npm run lint and npm run format descriptions Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

- Update .nvmrc from 16.* to 18.* — ESLint 9 requires Node >= 18 - Remove unreachable 'return Promise.resolve({})' in extensionRegistryExtensionsProvider() (dead code after a return) - Fix typo: metrics.mertricsInstance -> metrics.metricsInstance (getter, setter, and call site in runtimeSpy — internal only) - Change package lint scripts from 'eslint src --fix' to 'eslint src' so npm run lint / npm test does not auto-mutate the working tree; auto-fix is handled separately via npm run format Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Renaming the public getter/setter from mertricsInstance to metricsInstance caused a TS2300 duplicate identifier clash with the existing private backing field of the same name. Rename the private field to _metricsInstance to distinguish it from the public accessor. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Copilot

Pull request overview

Copilot reviewed 77 out of 80 changed files in this pull request and generated 9 comments.

Files not reviewed (2)

e2e/all-versions/guest-app/package-lock.json: Language not supported
e2e/all-versions/host-app/package-lock.json: Language not supported

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packages/uix-guest/src/guest.ts

  private async invokeAwaiter(
    invoker: RemoteMethodInvoker<unknown>,
    address: HostMethodAddress<unknown[]>,
  ): Promise<any> {
-    const final = setTimeout(() => {
-      return new Promise((resolve, reject) =>
-        reject(`${address} doesn't exist`),
-      );
-    }, 20000);
+    const final = setTimeout(
+      () => Promise.reject(`${address} doesn't exist`),
+      20000,
+    );
    const res = await this.invokeChecker(invoker, address);
+
    return new Promise((resolve) => {
      clearTimeout(final);
      return resolve(res);
    }).catch((e) => {
      clearTimeout(final);
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-return
      return e;
    });


packages/uix-guest/src/guest.test.ts

+  it("BUG: setTimeout callback returns an unhandled rejected Promise instead of rejecting the returned promise", async () => {
+    // Intercept setTimeout to capture the 20s timeout callback without
+    // triggering a real timer (and without jest fake timers, which prevent
+    // Promise microtasks from settling in this test environment).
+    const capturedCallbacks: Array<() => unknown> = [];
+
+    jest.spyOn(global, "setTimeout").mockImplementation(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      (cb: any, ms?: number) => {
+        if (ms === 20000) {
+          capturedCallbacks.push(cb);
+
+          return 0 as unknown as ReturnType<typeof setTimeout>;
+        }
+
+        return 0 as unknown as ReturnType<typeof setTimeout>;
+      },
+    );
+
+    const guest = new Guest({ id: "test-guest" });
+
+    // invokeChecker never resolves — simulates the host method not existing
+    jest
+      .spyOn(guest as unknown as GuestPrivate, "invokeChecker")
+      .mockReturnValue(
+        new Promise(() => {
+          /* noop */
+        }),
+      );
+
+    let isSettled = false;
+
+    (guest as unknown as GuestPrivate)
+      .invokeAwaiter(jest.fn(), testAddress)
+      .then(
+        () => {
+          isSettled = true;
+        },
+        () => {
+          isSettled = true;
+        },
+      );
+
+    await Promise.resolve(); // flush initial microtasks
+
+    expect(capturedCallbacks).toHaveLength(1);
+
+    // Fire the 20-second timeout callback manually
+    const callbackResult = capturedCallbacks[0]();
+
+    // BUG (1): The callback returns a rejected Promise — this is an unhandled
+    // rejection. The correct fix would be to reject the invokeAwaiter promise
+    // via a mechanism that's connected to the outer async function (e.g.
+    // Promise.race or a reject handle captured from the outer promise).
+    expect(callbackResult).toBeInstanceOf(Promise);
+    // Handle the rejection here so it doesn't become an unhandled rejection
+    await expect(callbackResult as Promise<unknown>).rejects.toMatch(
+      /doesn't exist/,
+    );
+
+    await Promise.resolve(); // flush remaining microtasks
+
+    // BUG (2): The awaiterPromise is still pending — the setTimeout callback
+    // rejection was never connected to it, so the caller will wait forever.
+    expect(isSettled).toBe(false);
+  });


packages/uix-host/eslint.config.mjs

+import { createConfig } from "../../eslint.base.mjs";
+
+export default createConfig({ tsconfigRootDir: import.meta.dirname });


packages/uix-host-react/eslint.config.mjs

+import { createConfig } from "../../eslint.base.mjs";
+
+export default createConfig({
+  tsconfigRootDir: import.meta.dirname,
+  includeReact: true,
+});


packages/uix-guest/eslint.config.mjs

+import { createConfig } from "../../eslint.base.mjs";
+
+export default createConfig({ tsconfigRootDir: import.meta.dirname });


packages/uix-core/eslint.config.mjs

+import { createConfig } from "../../eslint.base.mjs";
+
+export default createConfig({ tsconfigRootDir: import.meta.dirname });


jest.config.ts

@@ -4,6 +4,9 @@ const sdkProject = (sdkName: string, overrides: JestConfigWithTsJest) => ({
  displayName: `uix-${sdkName}`,
  testMatch: [`<rootDir>/packages/uix-${sdkName}/src/**/*.test.ts`],


CLAUDE.md

 npm run test:unit:watch   # Watch mode for unit tests
-npm run lint              # Check formatting and linting
-npm run format            # Auto-fix formatting issues
+npm run lint              # ESLint (--fix), Prettier check, and fixpack — all in parallel


.github/copilot-instructions.md

@@ -48,22 +48,31 @@ npm run format        # Runs `format:code` (Prettier --write) + `format:pkg` (fi
 npm run declarations:build
 ```

-`npm test` runs `lint → test:unit → test:subtests` sequentially via `run-s`. The `lint` step only runs the Prettier check and fixpack; it does not run ESLint. In workflows that invoke `npm test` (and in local pre-publish checks), all three must pass; do not skip the `lint` phase.
+`npm test` runs `lint → test:unit → test:subtests` sequentially via `run-s`. The `lint` step runs ESLint (with `--fix`), Prettier check, and fixpack in parallel. All three phases must pass; do not skip the `lint` phase.

 **Production build** (used in CI release): `npm run build:production`

 ## ESLint

-ESLint is configured via `.eslintrc.cjs` at the root (ESLint v8). It extends `eslint:recommended`, `plugin:@typescript-eslint/recommended`, and `plugin:@typescript-eslint/recommended-requiring-type-checking`. Two unsafe-assignment/unsafe-return rules are turned off; all other recommended TypeScript rules apply.
+ESLint 9 flat config. The shared factory is in `eslint.base.mjs` at the repo root; each package imports it in its own `eslint.config.mjs`. `npm run lint` runs `lint:eslint` (per-package `eslint src --fix`) in parallel with Prettier and fixpack.



…pace scripts npm run lint now runs ESLint in check-only mode (eslint src, no --fix). Auto-fixing ESLint violations requires running eslint src --fix manually inside the relevant package. Update CLAUDE.md and copilot-instructions.md to reflect this accurately. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Remove four high-churn, opinionated rules from eslint.base.mjs: - Remove sort-keys-fix entirely (alphabetic key ordering is unusual and breaks intentional semantic groupings) - Simplify padding-line-between-statements to only the import separator rule (remove 9 sub-rules enforcing blank lines around all statements) - Turn off func-style and arrow-body-style (style preferences with no correctness impact; function declarations have legitimate hoisting uses) - Turn off max-statements (max-lines-per-function: 75 already limits function size more meaningfully) Also remove now-unused eslint-disable-next-line max-statements comments from 7 src files that were suppressing the removed rule. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Copilot

Pull request overview

Copilot reviewed 77 out of 80 changed files in this pull request and generated 8 comments.

Files not reviewed (2)

e2e/all-versions/guest-app/package-lock.json: Language not supported
e2e/all-versions/host-app/package-lock.json: Language not supported

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packages/uix-guest/src/guest.ts

+    const final = setTimeout(
+      () => Promise.reject(`${address} doesn't exist`),
+      20000,
+    );
    const res = await this.invokeChecker(invoker, address);
+
    return new Promise((resolve) => {
      clearTimeout(final);
      return resolve(res);
    }).catch((e) => {
      clearTimeout(final);
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-return
      return e;
    });


packages/uix-core/src/message-wrapper.ts

  const keys = Object.keys(item);
  const hasRoot = keys.includes(NS_ROOT);
+
  if (hasRoot && keys.length != 1) {


packages/uix-core/src/types.ts

+// eslint-disable-next-line @typescript-eslint/no-unused-vars
 type ExtractKeys<T, U> = {
  [P in keyof T]: T[P] extends U ? P : never;
 }[keyof T];


packages/uix-host-react/src/hooks/useExtensions.ts

  const { host, error } = useHost();
+
  if (error) {
    return {
+      error,
      extensions: NO_EXTENSIONS,
      loading: false,
-      error,
    };
  }
+
+  /* eslint-disable react-hooks/rules-of-hooks, react-hooks/exhaustive-deps -- early return above is pre-existing; fixing requires a larger refactor */
  const [hostError, setHostError] = useState<Error>();
  const extensionPoints = useContext(ExtensibleComponentBoundaryContext);
  const boundryExtensionPointsAsString = extensionPoints?.map(


packages/uix-host-react/src/components/GuestUIFrame.tsx

  const ref = useRef<HTMLIFrameElement>();
  const { host } = useHost();
+
  if (!host) {
    return null;
  }
+
  const guest = host.guests.get(guestId);
  const frameUrl = new URL(src, guest.url.href);

+  /* eslint-disable react-hooks/rules-of-hooks, react-hooks/exhaustive-deps -- early return above is pre-existing; fixing requires a larger refactor */
  useEffect(() => {
    if (ref.current) {


packages/uix-host-react/src/components/GuestUIFrame.tsx

  const guest = host.guests.get(guestId);
  const frameUrl = new URL(src, guest.url.href);



packages/uix-host/src/port.ts

+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+export class Port<_GuestApi = unknown>
  extends Emitter<GuestConnectionEvents>
  implements GuestConnection


packages/uix-guest/src/guest.test.ts

+  it("BUG: setTimeout callback returns an unhandled rejected Promise instead of rejecting the returned promise", async () => {
+    // Intercept setTimeout to capture the 20s timeout callback without
+    // triggering a real timer (and without jest fake timers, which prevent
+    // Promise microtasks from settling in this test environment).
+    const capturedCallbacks: Array<() => unknown> = [];
+
+    jest.spyOn(global, "setTimeout").mockImplementation(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      (cb: any, ms?: number) => {
+        if (ms === 20000) {
+          capturedCallbacks.push(cb);
+
+          return 0 as unknown as ReturnType<typeof setTimeout>;
+        }
+
+        return 0 as unknown as ReturnType<typeof setTimeout>;
+      },
+    );
+
+    const guest = new Guest({ id: "test-guest" });
+
+    // invokeChecker never resolves — simulates the host method not existing
+    jest
+      .spyOn(guest as unknown as GuestPrivate, "invokeChecker")
+      .mockReturnValue(
+        new Promise(() => {
+          /* noop */
+        }),
+      );
+
+    let isSettled = false;
+
+    (guest as unknown as GuestPrivate)
+      .invokeAwaiter(jest.fn(), testAddress)
+      .then(
+        () => {
+          isSettled = true;
+        },
+        () => {
+          isSettled = true;
+        },
+      );
+
+    await Promise.resolve(); // flush initial microtasks
+
+    expect(capturedCallbacks).toHaveLength(1);
+
+    // Fire the 20-second timeout callback manually
+    const callbackResult = capturedCallbacks[0]();
+
+    // BUG (1): The callback returns a rejected Promise — this is an unhandled
+    // rejection. The correct fix would be to reject the invokeAwaiter promise
+    // via a mechanism that's connected to the outer async function (e.g.
+    // Promise.race or a reject handle captured from the outer promise).
+    expect(callbackResult).toBeInstanceOf(Promise);
+    // Handle the rejection here so it doesn't become an unhandled rejection
+    await expect(callbackResult as Promise<unknown>).rejects.toMatch(
+      /doesn't exist/,
+    );
+
+    await Promise.resolve(); // flush remaining microtasks
+
+    // BUG (2): The awaiterPromise is still pending — the setTimeout callback
+    // rejection was never connected to it, so the caller will wait forever.
+    expect(isSettled).toBe(false);
+  });


AmyJZhao added 6 commits February 19, 2026 00:59

linting and React

85d56a7

fix linting errors and react

41c356a

fix npm run build

6725b56

undo react hooks

2e99565

Merge branch 'main' into fix-linting-react

661978b

linting

3778d33

AmyJZhao requested a review from Copilot March 12, 2026 06:27

fix package-lock

11a090e

Copilot started reviewing on behalf of AmyJZhao March 12, 2026 06:54 View session

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fe-lix- and others added 4 commits March 12, 2026 13:46

Adding tests

7ff0672

Updating to the latest linting configuration

7a05aa6

Merge branch 'main' into fix-linting-react

d3a06ba

merge main

1154ab4

Copilot AI review requested due to automatic review settings March 16, 2026 15:29

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revert react hooks

660dc19

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fe-lix- and others added 5 commits March 17, 2026 11:50

Fixing issues with the linting configuration

1e388d8

All linting passing

f9a7f9f

Fixing linting

9c9be9f

Merge branch 'main' into fix-linting-react

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SITES-40700: fix linting/React#112

SITES-40700: fix linting/React#112
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	this.receiverTicketCache.set(boundFunction, fnTicket);
	this.receiverTicketCache.set(fn, fnTicket);

		"lint": "run-p lint:*",
		"lint:eslint": "npm run --workspaces --if-present lint",

		import { createConfig } from "../../eslint.base.mjs";

		export default createConfig({ tsconfigRootDir: import.meta.dirname });

		@@ -4,6 +4,9 @@ const sdkProject = (sdkName: string, overrides: JestConfigWithTsJest) => ({
		displayName: `uix-${sdkName}`,
		testMatch: [`<rootDir>/packages/uix-${sdkName}/src/*/.test.ts`],

		const guest = host.guests.get(guestId);
		const frameUrl = new URL(src, guest.url.href);

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