chore: release v8.12.6 @W-17528745

package.json

@@ -1,6 +1,6 @@
 {
     "name": "lwc-monorepo",
-    "version": "8.12.5",
+    "version": "8.12.6",
     "private": true,
     "description": "Lightning Web Components",
     "repository": {
@@ -24,6 +24,7 @@
         "test:ci": "vitest run --workspace vitest.workspace.mjs --coverage",
         "test:karma": "nx test @lwc/integration-karma",
         "test:karma:start": "nx start @lwc/integration-karma",
+        "test:hydration:start": "nx hydration:start @lwc/integration-karma",
         "test:integration": "nx sauce @lwc/integration-tests",
         "test:performance": "nx test @lwc/perf-benchmarks",
         "test:performance:best": "nx test:best @lwc/perf-benchmarks",
@@ -48,9 +49,9 @@
         "@swc/helpers": "~0.5.15",
         "@types/babel__core": "^7.20.5",
         "@types/node": "^22.10.7",
-        "@vitest/coverage-v8": "^2.1.8",
+        "@vitest/coverage-v8": "^3.0.3",
         "@vitest/eslint-plugin": "^1.1.25",
-        "@vitest/ui": "^2.1.8",
+        "@vitest/ui": "^3.0.3",
         "bytes": "^3.1.2",
         "es-module-lexer": "^1.6.0",
         "eslint": "9.18.0",
@@ -71,7 +72,7 @@
         "tslib": "^2.8.1",
         "typescript": "5.4.5",
         "typescript-eslint": "8.20.0",
-        "vitest": "^2.1.8"
+        "vitest": "^3.0.3"
     },
     "lint-staged": {
         "*.{js,mjs,ts}": "eslint --cache",

packages/@lwc/aria-reflection/package.json

@@ -4,7 +4,7 @@
         "You can safely modify dependencies, devDependencies, keywords, etc., but other props will be overwritten."
     ],
     "name": "@lwc/aria-reflection",
-    "version": "8.12.5",
+    "version": "8.12.6",
     "description": "ARIA element reflection polyfill for strings",
     "keywords": [
         "aom",

packages/@lwc/babel-plugin-component/package.json

@@ -4,7 +4,7 @@
         "You can safely modify dependencies, devDependencies, keywords, etc., but other props will be overwritten."
     ],
     "name": "@lwc/babel-plugin-component",
-    "version": "8.12.5",
+    "version": "8.12.6",
     "description": "Babel plugin to transform a LWC module",
     "keywords": [
         "lwc"
@@ -47,8 +47,8 @@
     },
     "dependencies": {
         "@babel/helper-module-imports": "7.25.9",
-        "@lwc/errors": "8.12.5",
-        "@lwc/shared": "8.12.5",
+        "@lwc/errors": "8.12.6",
+        "@lwc/shared": "8.12.6",
         "line-column": "~1.0.2"
     },
     "devDependencies": {

packages/@lwc/babel-plugin-component/src/__tests__/fixtures/wire-decorator/decorator-expects-a-function-identifier-as-first-parameter/actual.js

@@ -0,0 +1,4 @@
+import { wire, LightningElement } from "lwc";
+export default class Test extends LightningElement {
+  @wire(function adapter() {}, {}) wiredProp;
+}

packages/@lwc/babel-plugin-component/src/__tests__/fixtures/wire-decorator/decorator-expects-a-function-identifier-as-first-parameter/error.json

@@ -0,0 +1,10 @@
+{
+    "message": "LWC1097: @wire expects a function identifier as first parameter.",
+    "loc": {
+        "line": 3,
+        "column": 8,
+        "start": 107,
+        "length": 21
+    },
+    "filename": "test.js"
+}

packages/@lwc/babel-plugin-component/src/__tests__/fixtures/wire-decorator/decorator-rejects-computed-props/actual.js

@@ -0,0 +1,5 @@
+import { wire, LightningElement } from "lwc";
+import Foo from "foo";
+export default class Test extends LightningElement {
+  @wire(Foo['Bar'], {}) wiredProp;
+}

packages/@lwc/babel-plugin-component/src/__tests__/fixtures/wire-decorator/decorator-rejects-computed-props/error.json

@@ -0,0 +1,10 @@
+{
+    "message": "LWC1131: @wire identifier cannot contain computed properties",
+    "loc": {
+        "line": 4,
+        "column": 8,
+        "start": 130,
+        "length": 10
+    },
+    "filename": "test.js"
+}

packages/@lwc/babel-plugin-component/src/decorators/wire/validate.ts

@@ -25,60 +25,67 @@ function validateWireId(id: NodePath | undefined, path: NodePath, state: LwcBabe
         );
     }
 
-    const isMemberExpression = id.isMemberExpression();
+    let adapter: NodePath<types.Identifier>;
 
-    if (!id.isIdentifier() && !isMemberExpression) {
-        throw generateError(
-            id,
-            {
-                errorInfo: DecoratorErrors.FUNCTION_IDENTIFIER_SHOULD_BE_FIRST_PARAMETER,
-            },
-            state
-        );
-    }
+    if (id.isIdentifier()) {
+        // @wire(adapter)
+        adapter = id;
+    } else if (id.isMemberExpression()) {
+        if (id.node.computed) {
+            // @wire(adapter[computed])
+            throw generateError(
+                id,
+                {
+                    errorInfo: DecoratorErrors.FUNCTION_IDENTIFIER_CANNOT_HAVE_COMPUTED_PROPS,
+                },
+                state
+            );
+        }
 
-    if (id.isMemberExpression({ computed: true })) {
-        throw generateError(
-            id,
-            {
-                errorInfo: DecoratorErrors.FUNCTION_IDENTIFIER_CANNOT_HAVE_COMPUTED_PROPS,
-            },
-            state
-        );
-    }
+        const object = id.get('object');
 
-    // TODO [#3444]: improve member expression computed typechecking
-    // @ts-expect-error type narrowing incorrectly reduces id to `never`
-    if (isMemberExpression && !id.get('object').isIdentifier()) {
+        if (object.isIdentifier()) {
+            // @wire(adapter.foo)
+            adapter = object;
+        } else {
+            // @wire(adapter.foo.bar)
+            throw generateError(
+                id,
+                {
+                    errorInfo:
+                        DecoratorErrors.FUNCTION_IDENTIFIER_CANNOT_HAVE_NESTED_MEMBER_EXRESSIONS,
+                },
+                state
+            );
+        }
+    } else {
+        // @wire(1), @wire('adapter'), @wire(function adapter() {}), etc.
         throw generateError(
             id,
             {
-                errorInfo: DecoratorErrors.FUNCTION_IDENTIFIER_CANNOT_HAVE_NESTED_MEMBER_EXRESSIONS,
+                errorInfo: DecoratorErrors.FUNCTION_IDENTIFIER_SHOULD_BE_FIRST_PARAMETER,
             },
             state
         );
     }
 
-    // TODO [#3444]: improve member expression computed typechecking
     // Ensure wire adapter is imported (check for member expression or identifier)
-    // @ts-expect-error type narrowing incorrectly reduces id to `never`
-    const wireBinding = isMemberExpression ? id.node.object.name : id.node.name;
-    if (!path.scope.getBinding(wireBinding)) {
+    const adapterBinding = path.scope.getBinding(adapter.node.name);
+    if (!adapterBinding) {
         throw generateError(
             id,
             {
                 errorInfo: DecoratorErrors.WIRE_ADAPTER_SHOULD_BE_IMPORTED,
-                messageArgs: [id.node.name],
+                messageArgs: [adapter.node.name],
             },
             state
         );
     }
 
     // ensure wire adapter is a first parameter
     if (
-        wireBinding &&
-        !path.scope.getBinding(wireBinding)!.path.isImportSpecifier() &&
-        !path.scope.getBinding(wireBinding)!.path.isImportDefaultSpecifier()
+        !adapterBinding.path.isImportSpecifier() &&
+        !adapterBinding.path.isImportDefaultSpecifier()
     ) {
         throw generateError(
             id,

packages/@lwc/compiler/package.json

@@ -4,7 +4,7 @@
         "You can safely modify dependencies, devDependencies, keywords, etc., but other props will be overwritten."
     ],
     "name": "@lwc/compiler",
-    "version": "8.12.5",
+    "version": "8.12.6",
     "description": "LWC compiler",
     "keywords": [
         "lwc"
@@ -52,11 +52,11 @@
         "@babel/plugin-transform-class-properties": "7.25.9",
         "@babel/plugin-transform-object-rest-spread": "7.25.9",
         "@locker/babel-plugin-transform-unforgeables": "0.22.0",
-        "@lwc/babel-plugin-component": "8.12.5",
-        "@lwc/errors": "8.12.5",
-        "@lwc/shared": "8.12.5",
-        "@lwc/ssr-compiler": "8.12.5",
-        "@lwc/style-compiler": "8.12.5",
-        "@lwc/template-compiler": "8.12.5"
+        "@lwc/babel-plugin-component": "8.12.6",
+        "@lwc/errors": "8.12.6",
+        "@lwc/shared": "8.12.6",
+        "@lwc/ssr-compiler": "8.12.6",
+        "@lwc/style-compiler": "8.12.6",
+        "@lwc/template-compiler": "8.12.6"
     }
 }

packages/@lwc/compiler/src/transformers/__tests__/transform-html.spec.ts

@@ -9,10 +9,10 @@ import { APIVersion, noop } from '@lwc/shared';
 import { transformSync } from '../transformer';
 import type { TransformOptions } from '../../options';
 
-const TRANSFORMATION_OPTIONS: TransformOptions = {
+const TRANSFORMATION_OPTIONS = {
     namespace: 'x',
     name: 'foo',
-};
+} satisfies TransformOptions;
 
 describe('transformSync', () => {
     it('should throw when processing an invalid HTML file', () => {
@@ -74,7 +74,10 @@ describe('transformSync', () => {
         ];
         it.for(configs)('$name', ({ config, expected }) => {
             const template = `<template><img src="http://example.com/img.png" crossorigin="anonymous"></template>`;
-            const { code, warnings } = transformSync(template, 'foo.html', config);
+            const { code, warnings } = transformSync(template, 'foo.html', {
+                ...TRANSFORMATION_OPTIONS,
+                ...config,
+            });
             expect(warnings!.length).toBe(0);
             if (expected) {
                 expect(code).toContain('<img');

packages/@lwc/engine-core/package.json

@@ -4,7 +4,7 @@
         "You can safely modify dependencies, devDependencies, keywords, etc., but other props will be overwritten."
     ],
     "name": "@lwc/engine-core",
-    "version": "8.12.5",
+    "version": "8.12.6",
     "description": "Core LWC engine APIs.",
     "keywords": [
         "lwc"
@@ -46,9 +46,9 @@
         }
     },
     "dependencies": {
-        "@lwc/features": "8.12.5",
-        "@lwc/shared": "8.12.5",
-        "@lwc/signals": "8.12.5"
+        "@lwc/features": "8.12.6",
+        "@lwc/shared": "8.12.6",
+        "@lwc/signals": "8.12.6"
     },
     "devDependencies": {
         "observable-membrane": "2.0.0"

packages/@lwc/engine-core/src/framework/base-bridge-element.ts

@@ -150,7 +150,10 @@ export function HTMLBridgeElementFactory(
     const descriptors: PropertyDescriptorMap = create(null);
 
     // present a hint message so that developers are aware that they have not decorated property with @api
-    if (process.env.NODE_ENV !== 'production') {
+    // Note that we also don't do this in SSR because we cannot sniff for what props are declared on
+    // HTMLElementPrototype, and it seems not worth it to have these dev-only warnings there, since
+    // an `in` check could mistakenly assume that a prop is declared on a LightningElement prototype.
+    if (process.env.NODE_ENV !== 'production' && process.env.IS_BROWSER) {
         // TODO [#3761]: enable for components that don't extend from LightningElement
         if (!isUndefined(proto) && !isNull(proto) && !hasCustomSuperClass) {
             const nonPublicPropertiesToWarnOn = new Set(

packages/@lwc/engine-core/src/framework/hydration.ts

@@ -55,6 +55,13 @@ import { getScopeTokenClass } from './stylesheet';
 import { renderComponent } from './component';
 import { applyRefs } from './modules/refs';
 import { unwrapIfNecessary } from './sanitized-html-content';
+import {
+    logGlobalOperationEndWithVM,
+    logGlobalOperationStartWithVM,
+    logOperationEnd,
+    logOperationStart,
+    OperationId,
+} from './profiler';
 import type { Classes } from './hydration-utils';
 import type {
     VNodes,
@@ -85,6 +92,8 @@ let hasMismatch = false;
 export function hydrateRoot(vm: VM) {
     hasMismatch = false;
 
+    logGlobalOperationStartWithVM(OperationId.GlobalSsrHydrate, vm);
+
     runConnectedCallback(vm);
     hydrateVM(vm);
 
@@ -98,6 +107,7 @@ export function hydrateRoot(vm: VM) {
             logHydrationWarning('Hydration completed with errors.');
         }
     }
+    logGlobalOperationEndWithVM(OperationId.GlobalSsrHydrate, vm);
 }
 
 function hydrateVM(vm: VM) {
@@ -111,7 +121,9 @@ function hydrateVM(vm: VM) {
         renderRoot: parentNode,
         renderer: { getFirstChild },
     } = vm;
+    logOperationStart(OperationId.Patch, vm);
     hydrateChildren(getFirstChild(parentNode), children, parentNode, vm, false);
+    logOperationEnd(OperationId.Patch, vm);
     runRenderedCallback(vm);
 }
 

packages/@lwc/engine-core/src/framework/invoker.ts

@@ -11,9 +11,10 @@ import { addErrorComponentStack } from '../shared/error';
 import { evaluateTemplate, setVMBeingRendered, getVMBeingRendered } from './template';
 import { runWithBoundaryProtection } from './vm';
 import { logOperationStart, logOperationEnd, OperationId } from './profiler';
+import { LightningElement } from './base-lightning-element';
 import type { Template } from './template';
 import type { VM } from './vm';
-import type { LightningElement, LightningElementConstructor } from './base-lightning-element';
+import type { LightningElementConstructor } from './base-lightning-element';
 import type { VNodes } from './vnodes';
 
 export let isInvokingRender: boolean = false;
@@ -57,7 +58,11 @@ export function invokeComponentConstructor(vm: VM, Ctor: LightningElementConstru
         // the "instanceof" operator would not work here since Locker Service provides its own
         // implementation of LightningElement, so we indirectly check if the base constructor is
         // invoked by accessing the component on the vm.
-        if (vmBeingConstructed.component !== result) {
+        const isInvalidConstructor = lwcRuntimeFlags.LEGACY_LOCKER_ENABLED
+            ? vmBeingConstructed.component !== result
+            : !(result instanceof LightningElement);
+
+        if (isInvalidConstructor) {
             throw new TypeError(
                 'Invalid component constructor, the class should extend LightningElement.'
             );