chore: release v6.0.0

.github/workflows/karma.yml

@@ -55,8 +55,6 @@ jobs:
       - run: DISABLE_SYNTHETIC=1 yarn sauce:ci
       - run: LEGACY_BROWSERS=1 yarn sauce:ci
       - run: FORCE_NATIVE_SHADOW_MODE_FOR_TEST=1 yarn sauce:ci
-      - run: ENABLE_NATIVE_CUSTOM_ELEMENT_LIFECYCLE=1 yarn sauce:ci
-      - run: ENABLE_NATIVE_CUSTOM_ELEMENT_LIFECYCLE=1 DISABLE_SYNTHETIC=1 yarn sauce:ci
       - run: API_VERSION=58 yarn sauce:ci
       - run: API_VERSION=58 DISABLE_SYNTHETIC=1 yarn sauce:ci
       - run: API_VERSION=59 yarn sauce:ci

.github/workflows/unit.yml

@@ -64,5 +64,15 @@ jobs:
         run: yarn bundlesize
       - name: Run Jest tests
         run: yarn test:ci
+      - name: Upload Jest coverage report
+        uses: actions/upload-artifact@v3
+        with:
+            name: jest-coverage-report
+            path: coverage/
       - name: Run benchmark smoke tests
         run: CHROME_BINARY=${{ steps.setup-chrome.outputs.chrome-path }} BENCHMARK_SMOKE_TEST=1 yarn test:performance
+      - name: Add step summary
+        # 1. Remove leading/trailing "border" lines from output
+        # 2. Wrap file names in backticks
+        # 3. Convert leading whitespace to non-breaking to approximate plaintext output
+        run: sed -E '$d;1d;4,$s/^(  ?)([^ ]+)/\1`\2`/g;4,$s/^  /\ \ /g' coverage/coverage.txt >> "$GITHUB_STEP_SUMMARY"

package.json

@@ -1,6 +1,6 @@
 {
     "name": "lwc-monorepo",
-    "version": "5.3.0",
+    "version": "6.0.0",
     "private": true,
     "description": "Lightning Web Components",
     "repository": {

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": "5.3.0",
+    "version": "6.0.0",
     "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": "5.3.0",
+    "version": "6.0.0",
     "description": "Babel plugin to transform a LWC module",
     "keywords": [
         "lwc"
@@ -43,8 +43,8 @@
     },
     "dependencies": {
         "@babel/helper-module-imports": "7.22.15",
-        "@lwc/errors": "5.3.0",
-        "@lwc/shared": "5.3.0",
+        "@lwc/errors": "6.0.0",
+        "@lwc/shared": "6.0.0",
         "line-column": "~1.0.2"
     },
     "devDependencies": {

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": "5.3.0",
+    "version": "6.0.0",
     "description": "LWC compiler",
     "keywords": [
         "lwc"
@@ -48,10 +48,10 @@
         "@babel/plugin-proposal-object-rest-spread": "7.20.7",
         "@babel/plugin-transform-async-to-generator": "7.23.3",
         "@locker/babel-plugin-transform-unforgeables": "0.20.0",
-        "@lwc/babel-plugin-component": "5.3.0",
-        "@lwc/errors": "5.3.0",
-        "@lwc/shared": "5.3.0",
-        "@lwc/style-compiler": "5.3.0",
-        "@lwc/template-compiler": "5.3.0"
+        "@lwc/babel-plugin-component": "6.0.0",
+        "@lwc/errors": "6.0.0",
+        "@lwc/shared": "6.0.0",
+        "@lwc/style-compiler": "6.0.0",
+        "@lwc/template-compiler": "6.0.0"
     }
 }

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": "5.3.0",
+    "version": "6.0.0",
     "description": "Core LWC engine APIs.",
     "keywords": [
         "lwc"
@@ -42,8 +42,8 @@
         }
     },
     "dependencies": {
-        "@lwc/features": "5.3.0",
-        "@lwc/shared": "5.3.0"
+        "@lwc/features": "6.0.0",
+        "@lwc/shared": "6.0.0"
     },
     "devDependencies": {
         "observable-membrane": "2.0.0"

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

@@ -50,6 +50,8 @@ import {
     VText,
     VStaticPart,
     VStaticPartData,
+    isVBaseElement,
+    isVStatic,
 } from './vnodes';
 import { getComponentRegisteredName } from './component';
 
@@ -92,6 +94,7 @@ function st(fragment: Element, key: Key, parts?: VStaticPart[]): VStatic {
         fragment,
         owner,
         parts,
+        slotAssignment: undefined,
     };
 
     return vnode;
@@ -160,7 +163,7 @@ function h(sel: string, data: VElementData, children: VNodes = EmptyArray): VEle
         });
     }
 
-    const { key } = data;
+    const { key, slotAssignment } = data;
 
     const vnode: VElement = {
         type: VNodeType.Element,
@@ -170,6 +173,7 @@ function h(sel: string, data: VElementData, children: VNodes = EmptyArray): VEle
         elm: undefined,
         key,
         owner: vmBeingRendered,
+        slotAssignment,
     };
 
     return vnode;
@@ -207,6 +211,10 @@ function s(
         assert.isTrue(isObject(data), `s() 2nd argument data must be an object.`);
         assert.isTrue(isArray(children), `h() 3rd argument children must be an array.`);
     }
+
+    const vmBeingRendered = getVMBeingRendered()!;
+    const { renderMode, apiVersion } = vmBeingRendered;
+
     if (
         !isUndefined(slotset) &&
         !isUndefined(slotset.slotAssignments) &&
@@ -236,7 +244,6 @@ function s(
                 }
                 // If the passed slot content is factory, evaluate it and add the produced vnodes
                 if (assignedNodeIsScopedSlot) {
-                    const vmBeingRenderedInception = getVMBeingRendered();
                     // Evaluate in the scope of the slot content's owner
                     // if a slotset is provided, there will always be an owner. The only case where owner is
                     // undefined is for root components, but root components cannot accept slotted content
@@ -249,19 +256,34 @@ function s(
                             ArrayPush.call(newChildren, vnode.factory(data.slotData, data.key));
                         });
                     } finally {
-                        setVMBeingRendered(vmBeingRenderedInception);
+                        setVMBeingRendered(vmBeingRendered);
                     }
                 } else {
+                    // This block is for standard slots (non-scoped slots)
+                    let clonedVNode;
+                    if (
+                        renderMode === RenderMode.Light &&
+                        isAPIFeatureEnabled(APIFeature.USE_LIGHT_DOM_SLOT_FORWARDING, apiVersion) &&
+                        (isVBaseElement(vnode) || isVStatic(vnode)) &&
+                        // We only need to copy the vnodes when the slot assignment changes, copying every time causes issues with
+                        // disconnected/connected callback firing.
+                        vnode.slotAssignment !== data.slotAssignment
+                    ) {
+                        // When the light DOM slot assignment (slot attribute) changes we can't use the same reference
+                        // to the vnode because the current way the diffing algo works, it will replace the original reference
+                        // to the host element with a new one. This means the new element will be mounted and immediately unmounted.
+                        // Creating a copy of the vnode to preserve a reference to the previous host element.
+                        clonedVNode = { ...vnode, slotAssignment: data.slotAssignment };
+                    }
                     // If the slot content is standard type, the content is static, no additional
                     // processing needed on the vnode
-                    ArrayPush.call(newChildren, vnode);
+                    ArrayPush.call(newChildren, clonedVNode ?? vnode);
                 }
             }
         }
         children = newChildren;
     }
-    const vmBeingRendered = getVMBeingRendered()!;
-    const { renderMode, shadowMode, apiVersion } = vmBeingRendered;
+    const { shadowMode } = vmBeingRendered;
 
     if (renderMode === RenderMode.Light) {
         // light DOM slots - backwards-compatible behavior uses flattening, new behavior uses fragments
@@ -324,7 +346,7 @@ function c(
             });
         }
     }
-    const { key } = data;
+    const { key, slotAssignment } = data;
     let elm, aChildren, vm;
     const vnode: VCustomElement = {
         type: VNodeType.CustomElement,
@@ -333,6 +355,7 @@ function c(
         children,
         elm,
         key,
+        slotAssignment,
 
         ctor: Ctor,
         owner: vmBeingRendered,

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

@@ -49,7 +49,6 @@ import {
 import { componentValueObserved } from './mutation-tracker';
 import {
     patchCustomElementWithRestrictions,
-    patchLightningElementPrototypeWithRestrictions,
     patchShadowRootWithRestrictions,
 } from './restrictions';
 import { getVMBeingRendered, isUpdatingTemplate, Template } from './template';
@@ -851,7 +850,3 @@ defineProperty(LightningElement, 'CustomElementConstructor', {
     },
     configurable: true,
 });
-
-if (process.env.NODE_ENV !== 'production') {
-    patchLightningElementPrototypeWithRestrictions(LightningElement.prototype);
-}

packages/@lwc/engine-core/src/framework/modules/attrs.ts

@@ -15,7 +15,7 @@ import {
 import { RendererAPI } from '../renderer';
 
 import { EmptyObject } from '../utils';
-import { VBaseElement } from '../vnodes';
+import { VBaseElement, VStatic } from '../vnodes';
 
 const ColonCharCode = 58;
 
@@ -63,3 +63,24 @@ export function patchAttributes(
         }
     }
 }
+
+export function patchSlotAssignment(
+    oldVnode: VBaseElement | VStatic | null,
+    vnode: VBaseElement | VStatic,
+    renderer: RendererAPI
+) {
+    const { slotAssignment } = vnode;
+
+    if (oldVnode?.slotAssignment === slotAssignment) {
+        return;
+    }
+
+    const { elm } = vnode;
+    const { setAttribute, removeAttribute } = renderer;
+
+    if (isUndefined(slotAssignment) || isNull(slotAssignment)) {
+        removeAttribute(elm, 'slot');
+    } else {
+        setAttribute(elm, 'slot', slotAssignment);
+    }
+}

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

@@ -62,7 +62,11 @@ export interface RendererAPI {
     isConnected: (node: N) => boolean;
     insertStylesheet: (content: string, target?: ShadowRoot) => void;
     assertInstanceOfHTMLElement: (elm: any, msg: string) => void;
-    createCustomElement: (tagName: string, upgradeCallback: LifecycleCallback) => E;
+    createCustomElement: (
+        tagName: string,
+        upgradeCallback: LifecycleCallback,
+        useNativeLifecycle: boolean
+    ) => E;
     defineCustomElement: (tagName: string) => void;
     ownerDocument(elm: E): Document;
     registerContextConsumer: (

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

@@ -24,7 +24,7 @@ import {
 import { logError } from '../shared/logger';
 import { getComponentTag } from '../shared/format';
 import { RendererAPI } from './renderer';
-import { EmptyArray } from './utils';
+import { EmptyArray, shouldUseNativeCustomElementLifecycle } from './utils';
 import { markComponentAsDirty } from './component';
 import { getScopeTokenClass } from './stylesheet';
 import { lockDomMutation, patchElementWithRestrictions, unlockDomMutation } from './restrictions';
@@ -47,6 +47,7 @@ import {
     isVCustomElement,
     isVFragment,
     isVScopedSlotFragment,
+    isVStatic,
     Key,
     VBaseElement,
     VComment,
@@ -60,7 +61,7 @@ import {
     VText,
 } from './vnodes';
 
-import { patchAttributes } from './modules/attrs';
+import { patchAttributes, patchSlotAssignment } from './modules/attrs';
 import { patchProps } from './modules/props';
 import { patchClassAttribute } from './modules/computed-class-attr';
 import { patchStyleAttribute } from './modules/computed-style-attr';
@@ -69,6 +70,7 @@ import { applyStaticClassAttribute } from './modules/static-class-attr';
 import { applyStaticStyleAttribute } from './modules/static-style-attr';
 import { applyRefs } from './modules/refs';
 import { applyStaticParts } from './modules/static-parts';
+import { LightningElementConstructor } from './base-lightning-element';
 
 export function patchChildren(
     c1: VNodes,
@@ -265,6 +267,8 @@ function mountElement(
 function patchStatic(n1: VStatic, n2: VStatic, renderer: RendererAPI) {
     const elm = (n2.elm = n1.elm!);
 
+    // slotAssignments can only apply to the top level element, never to a static part.
+    patchSlotAssignment(n1, n2, renderer);
     // The `refs` object is blown away in every re-render, so we always need to re-apply them
     applyStaticParts(elm, n2, renderer, false);
 }
@@ -298,6 +302,8 @@ function mountStatic(
         }
     }
 
+    // slotAssignments can only apply to the top level element, never to a static part.
+    patchSlotAssignment(null, vnode, renderer);
     insertNode(elm, parent, anchor, renderer);
     applyStaticParts(elm, vnode, renderer, true);
 }
@@ -308,7 +314,7 @@ function mountCustomElement(
     anchor: Node | null,
     renderer: RendererAPI
 ) {
-    const { sel, owner } = vnode;
+    const { sel, owner, ctor } = vnode;
     const { createCustomElement } = renderer;
     /**
      * Note: if the upgradable constructor does not expect, or throw when we new it
@@ -328,7 +334,10 @@ function mountCustomElement(
     // compiler may generate tagnames with uppercase letters so - for backwards
     // compatibility, we lower case the tagname here.
     const normalizedTagname = sel.toLowerCase();
-    const elm = createCustomElement(normalizedTagname, upgradeCallback);
+    const useNativeLifecycle = shouldUseNativeCustomElementLifecycle(
+        ctor as LightningElementConstructor
+    );
+    const elm = createCustomElement(normalizedTagname, upgradeCallback, useNativeLifecycle);
 
     vnode.elm = elm;
     vnode.vm = vm;
@@ -345,7 +354,7 @@ function mountCustomElement(
 
     if (vm) {
         if (process.env.IS_BROWSER) {
-            if (!lwcRuntimeFlags.ENABLE_NATIVE_CUSTOM_ELEMENT_LIFECYCLE) {
+            if (!useNativeLifecycle) {
                 if (process.env.NODE_ENV !== 'production') {
                     // With synthetic lifecycle callbacks, it's possible for elements to be removed without the engine
                     // noticing it (e.g. `appendChild` the same host element twice). This test ensures we don't regress.
@@ -597,6 +606,7 @@ function patchElementPropsAndAttrsAndRefs(
 
     patchAttributes(oldVnode, vnode, renderer);
     patchProps(oldVnode, vnode, renderer);
+    patchSlotAssignment(oldVnode, vnode, renderer);
 
     // The `refs` object is blown away in every re-render, so we always need to re-apply them
     applyRefs(vnode, vnode.owner);
@@ -795,8 +805,8 @@ function allocateInSlot(vm: VM, children: VNodes, owner: VM) {
         }
 
         let slotName: unknown = '';
-        if (isVBaseElement(vnode)) {
-            slotName = vnode.data.attrs?.slot ?? '';
+        if (isVBaseElement(vnode) || isVStatic(vnode)) {
+            slotName = vnode.slotAssignment ?? '';
         } else if (isVScopedSlotFragment(vnode)) {
             slotName = vnode.slotName;
         }