[IMP] big change: shallow render

With this commit, component only render child
components if they have different props (shallow
equality). Otherwise, we trust the reactivity
system to make sure that all impacted components
are updated

src/app/template_helpers.ts

@@ -2,6 +2,8 @@ import { BDom, multi, text, toggler } from "../blockdom";
 import { validateProps } from "../component/props_validation";
 import { Markup } from "../utils";
 import { html } from "../blockdom/index";
+import { TARGET } from "../reactivity";
+
 /**
  * This file contains utility functions that will be injected in each template,
  * to perform various useful tasks in the compiled code.
@@ -21,7 +23,8 @@ function callSlot(
   defaultContent?: (ctx: any, node: any, key: string) => BDom
 ): BDom {
   key = key + "__slot_" + name;
-  const slots = (ctx.props && ctx.props.slots) || {};
+  const nonReactiveProps = ctx.props && ctx.props[TARGET];
+  const slots = nonReactiveProps ? nonReactiveProps.slots || {} : {};
   const { __render, __ctx, __scope } = slots[name] || {};
   const slotScope = Object.create(__ctx || {});
   if (__scope) {

src/app/template_set.ts

@@ -55,7 +55,7 @@ export class TemplateSet {
       const template = this.getTemplate(subTemplate);
       return toggler(subTemplate, template.call(owner, ctx, parent, key));
     },
-    getTemplate: (name: string, nameSpace?: string) => this.getTemplate(name, nameSpace),
+    getTemplate: (name: string) => this.getTemplate(name),
   });
 
   constructor(config: TemplateSetConfig = {}) {
@@ -87,15 +87,13 @@ export class TemplateSet {
     }
   }
 
-  getTemplate(name: string, nameSpace?: string): Template {
+  getTemplate(name: string): Template {
-
     if (!(name in this.templates)) {
       const rawTemplate = this.rawTemplates[name];
       if (rawTemplate === undefined) {
         throw new Error(`Missing template: "${name}"`);
       }
-          console.log("getTemplate", nameSpace);
+      const templateFn = this._compileTemplate(name, rawTemplate);
-      const templateFn = this._compileTemplate(name, rawTemplate, nameSpace);
       // first add a function to lazily get the template, in case there is a
       // recursive call to the template name
       const templates = this.templates;
@@ -108,14 +106,12 @@ export class TemplateSet {
     return this.templates[name];
   }
 
-  _compileTemplate(name: string, template: string | Node, nameSpace?: string) {
+  _compileTemplate(name: string, template: string | Node) {
-    console.log("CompileTpm", nameSpace)
     return compile(template, {
       name,
       dev: this.dev,
       translateFn: this.translateFn,
       translatableAttributes: this.translatableAttributes,
-      nameSpace: nameSpace,
     });
   }
 }

src/compiler/code_generator.ts

@@ -33,7 +33,6 @@ export interface Config {
 export interface CodeGenOptions extends Config {
   hasSafeContext?: boolean;
   name?: string;
-  nameSpace?: string;
 }
 
 // using a non-html document so that <inner/outer>HTML serializes as XML instead
@@ -215,9 +214,8 @@ export class CodeGenerator {
   translateFn: (s: string) => string;
   translatableAttributes: string[];
   ast: AST;
-  staticCalls: { id: string; template: string, nameSpace?: string }[] = [];
+  staticCalls: { id: string; template: string }[] = [];
   helpers: Set<string> = new Set();
-  nameSpace?: string;
 
   constructor(ast: AST, options: CodeGenOptions) {
     this.translateFn = options.translateFn || ((s: string) => s);
@@ -226,8 +224,6 @@ export class CodeGenerator {
     this.dev = options.dev || false;
     this.ast = ast;
     this.templateName = options.name;
-    this.nameSpace = options.nameSpace;
-    console.log('ThisNS', this.nameSpace)
   }
 
   generateCode(): string {
@@ -242,7 +238,6 @@ export class CodeGenerator {
       isLast: true,
       translate: true,
       tKeyExpr: null,
-      nameSpace: this.nameSpace,
     });
     // define blocks and utility functions
     let mainCode = [
@@ -255,12 +250,8 @@ export class CodeGenerator {
       mainCode.push(`// Template name: "${this.templateName}"`);
     }
 
-    for (let { id, template, nameSpace } of this.staticCalls) {
+    for (let { id, template } of this.staticCalls) {
-      let ns;
+      mainCode.push(`const ${id} = getTemplate(${template});`);
-      if (nameSpace) {
-        ns = `, "${nameSpace}"`;
-      }
-      mainCode.push(`const ${id} = getTemplate(${template}${ns});`);
     }
 
     // define all blocks
@@ -548,7 +539,6 @@ export class CodeGenerator {
     // attributes
     const attrs: { [key: string]: string } = {};
     const nameSpace = ast.ns || ctx.nameSpace;
-    console.log(nameSpace)
     if (nameSpace && isNewBlock) {
       // specific namespace uri
       attrs["block-ns"] = nameSpace;
@@ -970,7 +960,7 @@ export class CodeGenerator {
     } else {
       const id = this.generateId(`callTemplate_`);
       this.helpers.add("getTemplate");
-      this.staticCalls.push({ id, template: subTemplate, nameSpace: ctx.nameSpace });
+      this.staticCalls.push({ id, template: subTemplate });
       block = this.createBlock(block, "multi", ctx);
       this.insertBlock(`${id}.call(this, ctx, node, ${key})`, block!, {
         ...ctx,
@@ -1091,11 +1081,9 @@ export class CodeGenerator {
 
     let propString = propStr;
     if (ast.dynamicProps) {
-      if (!props.length) {
+      propString = `Object.assign({}, ${compileExpr(ast.dynamicProps)}${
-        propString = `${compileExpr(ast.dynamicProps)}`;
+        props.length ? ", " + propStr : ""
-      } else {
+      })`;
-        propString = `Object.assign({}, ${compileExpr(ast.dynamicProps)}, ${propStr})`;
-      }
     }
 
     let propVar: string;

src/compiler/index.ts

@@ -8,7 +8,6 @@ export type TemplateFunction = (blocks: any, utils: any) => Template;
 
 interface CompileOptions extends Config {
   name?: string;
-  nameSpace?: string,
 }
 export function compile(template: string | Node, options: CompileOptions = {}): TemplateFunction {
   // parsing
@@ -21,10 +20,8 @@ export function compile(template: string | Node, options: CompileOptions = {}):
       : !template.includes("t-set") && !template.includes("t-call");
 
   // code generation
-  console.log("compile", options)
   const codeGenerator = new CodeGenerator(ast, { ...options, hasSafeContext });
   const code = codeGenerator.generateCode();
-  console.log(code)
   // template function
   return new Function("bdom, helpers", code) as TemplateFunction;
 }

src/component/component.ts

@@ -20,7 +20,7 @@ export class Component<Props = any, Env = any> {
 
   setup() {}
 
-  render() {
+  render(force: boolean = false) {
-    this.__owl__.render();
+    this.__owl__.render(force);
   }
 }

src/component/component_node.ts

@@ -1,6 +1,9 @@
 import type { App, Env } from "../app/app";
 import { BDom, VNode } from "../blockdom";
+import { clearReactivesForCallback, Reactive, reactive, TARGET } from "../reactivity";
+import { batched, Callback } from "../utils";
 import { Component } from "./component";
+import { fibersInError, handleError } from "./error_handling";
 import {
   Fiber,
   makeChildFiber,
@@ -9,7 +12,6 @@ import {
   MountOptions,
   RootFiber,
 } from "./fibers";
-import { handleError, fibersInError } from "./error_handling";
 import { applyDefaultProps } from "./props_validation";
 import { STATUS } from "./status";
 
@@ -23,6 +25,46 @@ export function useComponent(): Component {
   return currentNode!.component;
 }
 
+// -----------------------------------------------------------------------------
+// Integration with reactivity system (useState)
+// -----------------------------------------------------------------------------
+
+const batchedRenderFunctions = new WeakMap<ComponentNode, Callback>();
+/**
+ * Creates a reactive object that will be observed by the current component.
+ * Reading data from the returned object (eg during rendering) will cause the
+ * component to subscribe to that data and be rerendered when it changes.
+ *
+ * @param state the state to observe
+ * @returns a reactive object that will cause the component to re-render on
+ *  relevant changes
+ * @see reactive
+ */
+export function useState<T extends object>(state: T): Reactive<T> {
+  const node = currentNode!;
+  let render = batchedRenderFunctions.get(node)!;
+  if (!render) {
+    render = batched(node.render.bind(node));
+    batchedRenderFunctions.set(node, render);
+    // manual implementation of onWillUnmount to break cyclic dependency
+    node.willUnmount.unshift(clearReactivesForCallback.bind(null, render));
+  }
+  return reactive(state, render);
+}
+
+// -----------------------------------------------------------------------------
+// component function (used in compiled template code)
+// -----------------------------------------------------------------------------
+type Props = { [key: string]: any };
+
+function arePropsDifferent(props1: Props, props2: Props): boolean {
+  for (let k in props1) {
+    if (props1[k] !== props2[k]) {
+      return true;
+    }
+  }
+  return false;
+}
 export function component(
   name: string | typeof Component,
   props: any,
@@ -47,7 +89,10 @@ export function component(
 
   const parentFiber = ctx.fiber!;
   if (node) {
+    const currentProps = node.component.props[TARGET];
+    if (parentFiber.force || arePropsDifferent(currentProps, props)) {
       node.updateAndRender(props, parentFiber);
+    }
   } else {
     // new component
     let C;
@@ -69,7 +114,7 @@ export function component(
 }
 
 // -----------------------------------------------------------------------------
-//  Component VNode
+//  Component VNode class
 // -----------------------------------------------------------------------------
 
 type LifecycleHook = Function;
@@ -107,6 +152,7 @@ export class ComponentNode<T extends typeof Component = typeof Component>
     applyDefaultProps(props, C);
     const env = (parent && parent.childEnv) || app.env;
     this.childEnv = env;
+    props = useState(props);
     this.component = new C(props, env, this) as any;
     this.renderFn = app.getTemplate(C.template).bind(this.component, this.component, this);
     this.component.setup();
@@ -135,7 +181,7 @@ export class ComponentNode<T extends typeof Component = typeof Component>
     }
   }
 
-  async render() {
+  async render(force: boolean = false) {
     let current = this.fiber;
     if (current && current.root!.locked) {
       await Promise.resolve();
@@ -143,13 +189,15 @@ export class ComponentNode<T extends typeof Component = typeof Component>
       current = this.fiber;
     }
     if (current && !current.bdom && !fibersInError.has(current)) {
+      if (current.force || force === false) {
         return;
       }
+    }
     if (!this.bdom && !current) {
       return;
     }
 
-    const fiber = makeRootFiber(this);
+    const fiber = makeRootFiber(this, force);
     this.fiber = fiber;
     this.app.scheduler.addFiber(fiber);
     await Promise.resolve();
@@ -211,6 +259,9 @@ export class ComponentNode<T extends typeof Component = typeof Component>
     this.fiber = fiber;
     const component = this.component;
     applyDefaultProps(props, component.constructor as any);
+
+    currentNode = this;
+    props = useState(props);
     const prom = Promise.all(this.willUpdateProps.map((f) => f.call(component, props)));
     await prom;
     if (fiber !== this.fiber) {
@@ -275,6 +326,14 @@ export class ComponentNode<T extends typeof Component = typeof Component>
   }
 
   patch() {
+    if (this.fiber && this.fiber.parent) {
+      // we only patch here renderings coming from above. renderings initiated
+      // by the component will be patched independently in the appropriate
+      // fiber.complete
+      this._patch();
+    }
+  }
+  _patch() {
     const hasChildren = Object.keys(this.children).length > 0;
     this.bdom!.patch(this!.fiber!.bdom!, hasChildren);
     if (hasChildren) {

src/component/fibers.ts

@@ -13,7 +13,7 @@ export function makeChildFiber(node: ComponentNode, parent: Fiber): Fiber {
   return new Fiber(node, parent);
 }
 
-export function makeRootFiber(node: ComponentNode): Fiber {
+export function makeRootFiber(node: ComponentNode, force: boolean): Fiber {
   let current = node.fiber;
   if (current) {
     let root = current.root!;
@@ -21,6 +21,7 @@ export function makeRootFiber(node: ComponentNode): Fiber {
     current.children = [];
     root.counter++;
     current.bdom = null;
+    current.force = force;
     if (fibersInError.has(current)) {
       fibersInError.delete(current);
       fibersInError.delete(root);
@@ -35,7 +36,7 @@ export function makeRootFiber(node: ComponentNode): Fiber {
   if (node.patched.length) {
     fiber.patched.push(fiber);
   }
-
+  fiber.force = force;
   return fiber;
 }
 
@@ -62,11 +63,13 @@ export class Fiber {
   parent: Fiber | null;
   children: Fiber[] = [];
   appliedToDom = false;
+  force: boolean = false;
 
   constructor(node: ComponentNode, parent: Fiber | null) {
     this.node = node;
     this.parent = parent;
     if (parent) {
+      this.force = parent.force;
       const root = parent.root!;
       root.counter++;
       this.root = root;
@@ -109,7 +112,7 @@ export class RootFiber extends Fiber {
       current = undefined;
 
       // Step 2: patching the dom
-      node.patch();
+      node._patch();
       this.locked = false;
 
       // Step 4: calling all mounted lifecycle hooks

src/index.ts

@@ -42,7 +42,8 @@ export { useComponent } from "./component/component_node";
 export { status } from "./component/status";
 export { Memo } from "./memo";
 export { xml } from "./app/template_set";
-export { useState, reactive } from "./reactivity";
+export { reactive } from "./reactivity";
+export { useState } from "./component/component_node";
 export { useEffect, useEnv, useExternalListener, useRef, useSubEnv } from "./hooks";
 export { EventBus, whenReady, loadFile, markup } from "./utils";
 export {

src/reactivity.ts

@@ -1,9 +1,7 @@
-import { onWillUnmount } from "./component/lifecycle_hooks";
+import { Callback } from "./utils";
-import { ComponentNode, getCurrent } from "./component/component_node";
-import { batched, Callback } from "./utils";
 
 // Allows to get the target of a Reactive (used for making a new Reactive from the underlying object)
-const TARGET = Symbol("Target");
+export const TARGET = Symbol("Target");
 // Special key to subscribe to, to be notified of key creation/deletion
 const KEYCHANGES = Symbol("Key changes");
 
@@ -85,7 +83,7 @@ const callbacksToTargets = new WeakMap<Callback, Set<Target>>();
  *
  * @param callback the callback for which the reactives need to be cleared
  */
-function clearReactivesForCallback(callback: Callback): void {
+export function clearReactivesForCallback(callback: Callback): void {
   const targetsToClear = callbacksToTargets.get(callback);
   if (!targetsToClear) {
     return;
@@ -190,28 +188,3 @@ export function reactive<T extends Target>(target: T, callback: Callback = () =>
   }
   return reactivesForTarget.get(callback) as Reactive<T>;
 }
-
-const batchedRenderFunctions = new WeakMap<ComponentNode, Callback>();
-/**
- * Creates a reactive object that will be observed by the current component.
- * Reading data from the returned object (eg during rendering) will cause the
- * component to subscribe to that data and be rerendered when it changes.
- *
- * @param state the state to observe
- * @returns a reactive object that will cause the component to re-render on
- *  relevant changes
- * @see reactive
- */
-export function useState<T extends object>(state: T): Reactive<T> {
-  const node = getCurrent()!;
-  if (!batchedRenderFunctions.has(node)) {
-    batchedRenderFunctions.set(
-      node,
-      batched(() => node.render())
-    );
-    onWillUnmount(() => clearReactivesForCallback(render));
-  }
-  const render = batchedRenderFunctions.get(node)!;
-  const reactiveState = reactive(state, render);
-  return reactiveState;
-}

tests/compiler/__snapshots__/svg.test.ts.snap

@@ -52,35 +52,6 @@ exports[`properly support svg namespace to svg tags added even if already in svg
 }"
 `;
 
-exports[`properly support svg svg namespace added to sub-blocks (t-call) 1`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`path\`, \\"http://www.w3.org/2000/svg\\");
-  
-  let block1 = createBlock(\`<svg block-ns=\\"http://www.w3.org/2000/svg\\"><block-child-0/></svg>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    let b2 = callTemplate_1.call(this, ctx, node, key + \`__1\`);
-    return block1([], [b2]);
-  }
-}"
-`;
-
-exports[`properly support svg svg namespace added to sub-blocks (t-call) 2`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  
-  let block1 = createBlock(\`<path/>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    return block1();
-  }
-}"
-`;
-
 exports[`properly support svg svg namespace added to sub-blocks 1`] = `
 "function anonymous(bdom, helpers
 ) {

tests/compiler/svg.test.ts

@@ -1,7 +1,5 @@
 import { renderToString, renderToBdom, snapshotEverything, makeTestFixture } from "../helpers";
 import { mount } from "../../src/blockdom";
-import { mount as mountComponent, Component } from "../../src/index"
-
 // NB: check the snapshots to see where the SVG namespaces are added
 snapshotEverything();
 
@@ -54,24 +52,4 @@ describe("properly support svg", () => {
       expect(el.namespaceURI).toBe("http://www.w3.org/2000/svg");
     }
   });
-
-  test.only("svg namespace added to sub-blocks (t-call)", async () => {
-    const templates = `<t>
-      <t t-name="svg"><svg><t t-call="path" /></svg></t>
-      <t t-name="path"><path /></t>
-    </t>
-    `
-    const fixture = makeTestFixture();
-
-    class Svg extends Component {
-      static template = "svg";
-    }
-
-    await mountComponent(Svg, fixture, {templates})
-    const elems = fixture.querySelectorAll("svg, path");
-    expect(elems.length).toEqual(2);
-    for (const el of elems) {
-      expect(el.namespaceURI).toBe("http://www.w3.org/2000/svg");
-    }
-  });
 });

tests/components/__snapshots__/basics.test.ts.snap

@@ -968,7 +968,7 @@ exports[`basics update props of component without concrete own node 1`] = `
   
   return function template(ctx, node, key = \\"\\") {
     const tKey_1 = ctx['childProps'].key;
-    let b2 = toggler(tKey_1, component(\`Child\`, ctx['childProps'], tKey_1 + key + \`__1\`, node, ctx));
+    let b2 = toggler(tKey_1, component(\`Child\`, Object.assign({}, ctx['childProps']), tKey_1 + key + \`__1\`, node, ctx));
     return block1([], [b2]);
   }
 }"

tests/components/__snapshots__/concurrency.test.ts.snap

@@ -1145,7 +1145,7 @@ exports[`properly behave when destroyed/unmounted while rendering  2`] = `
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    let b2 = component(\`SubChild\`, {}, key + \`__1\`, node, ctx);
+    let b2 = component(\`SubChild\`, {val: ctx['props'].val}, key + \`__1\`, node, ctx);
     return block1([], [b2]);
   }
 }"

tests/components/__snapshots__/lifecycle.test.ts.snap

@@ -499,7 +499,7 @@ exports[`lifecycle hooks onWillRender 1`] = `
   let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
-    return component(\`Child\`, {}, key + \`__1\`, node, ctx);
+    return component(\`Child\`, {someValue: ctx['state'].value}, key + \`__1\`, node, ctx);
   }
 }"
 `;

tests/components/__snapshots__/rendering.test.ts.snap

@@ -0,0 +1,163 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`force render in case of existing render 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return component(\`B\`, {val: ctx['state'].val}, key + \`__1\`, node, ctx);
+  }
+}"
+`;
+
+exports[`force render in case of existing render 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    let b2 = component(\`C\`, {}, key + \`__1\`, node, ctx);
+    let b3 = text(ctx['props'].val);
+    return multi([b2, b3]);
+  }
+}"
+`;
+
+exports[`force render in case of existing render 3`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(\`C\`);
+  }
+}"
+`;
+
+exports[`rendering semantics can force a render to update sub tree 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    let b2 = text(ctx['state'].value);
+    let b3 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
+    return multi([b2, b3]);
+  }
+}"
+`;
+
+exports[`rendering semantics can force a render to update sub tree 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(\`child\`);
+  }
+}"
+`;
+
+exports[`rendering semantics can render a parent without rendering child 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    let b2 = text(ctx['state'].value);
+    let b3 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
+    return multi([b2, b3]);
+  }
+}"
+`;
+
+exports[`rendering semantics can render a parent without rendering child 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(\`child\`);
+  }
+}"
+`;
+
+exports[`rendering semantics props are reactive (nested prop) 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return component(\`Child\`, {a: ctx['state']}, key + \`__1\`, node, ctx);
+  }
+}"
+`;
+
+exports[`rendering semantics props are reactive (nested prop) 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(ctx['props'].a.b.c);
+  }
+}"
+`;
+
+exports[`rendering semantics props are reactive 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return component(\`Child\`, {a: ctx['state']}, key + \`__1\`, node, ctx);
+  }
+}"
+`;
+
+exports[`rendering semantics props are reactive 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(ctx['props'].a.b);
+  }
+}"
+`;
+
+exports[`rendering semantics rendering is atomic (for one subtree) 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    let b2 = text(ctx['state'].obj.val);
+    let b3 = component(\`B\`, {obj: ctx['state'].obj}, key + \`__1\`, node, ctx);
+    return multi([b2, b3]);
+  }
+}"
+`;
+
+exports[`rendering semantics rendering is atomic (for one subtree) 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return component(\`C\`, {obj: ctx['props'].obj}, key + \`__1\`, node, ctx);
+  }
+}"
+`;
+
+exports[`rendering semantics rendering is atomic (for one subtree) 3`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(ctx['props'].obj.val);
+  }
+}"
+`;

tests/components/__snapshots__/t_props.test.ts.snap

@@ -8,7 +8,7 @@ exports[`t-props basic use 1`] = `
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    let b2 = component(\`Child\`, ctx['some'].obj, key + \`__1\`, node, ctx);
+    let b2 = component(\`Child\`, Object.assign({}, ctx['some'].obj), key + \`__1\`, node, ctx);
     return block1([], [b2]);
   }
 }"
@@ -65,7 +65,7 @@ exports[`t-props t-props only 1`] = `
   let block1 = createBlock(\`<div><div><block-child-0/></div></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    let b2 = component(\`Comp\`, ctx['state'], key + \`__1\`, node, ctx);
+    let b2 = component(\`Comp\`, Object.assign({}, ctx['state']), key + \`__1\`, node, ctx);
     return block1([], [b2]);
   }
 }"

tests/components/basics.test.ts

@@ -121,7 +121,7 @@ describe("basics", () => {
     class Test extends Component {
       static template = xml`<span>simple vnode</span>`;
       setup() {
-        expect(this.props).toBe(p);
+        expect(this.props).not.toBe(p);
       }
     }
 

tests/components/concurrency.test.ts

@@ -39,6 +39,8 @@ Scheduler.prototype.addFiber = function (fiber: Fiber) {
 
 afterEach(() => {
   if (lastScheduler && lastScheduler.tasks.size > 0) {
+    // we still clear the scheduler to prevent additional noise
+    lastScheduler.tasks.clear();
     throw new Error("we got a memory leak...");
   }
 });
@@ -521,7 +523,7 @@ test("properly behave when destroyed/unmounted while rendering ", async () => {
   }
 
   class Child extends Component {
-    static template = xml`<div><SubChild /></div>`;
+    static template = xml`<div><SubChild val="props.val"/></div>`;
     static components = { SubChild };
     setup() {
       useLogLifecycle();
@@ -1907,18 +1909,13 @@ test("concurrent renderings scenario 13", async () => {
   await nextTick(); // wait for this change to be applied
   expect([
     "Parent:willRender",
-    "Child:willUpdateProps",
     "Child:setup",
     "Child:willStart",
     "Parent:rendered",
     "Child:willRender",
     "Child:rendered",
-    "Child:willRender",
-    "Child:rendered",
     "Parent:willPatch",
-    "Child:willPatch",
     "Child:mounted",
-    "Child:patched",
     "Parent:patched",
     "Child:willRender",
     "Child:rendered",
@@ -2472,9 +2469,9 @@ test("two renderings initiated between willPatch and patched", async () => {
       useLogLifecycle();
       onMounted(() => {
         this.mounted = "Mounted";
-        parent.render();
+        parent.render(true);
       });
-      onWillUnmount(() => parent.render());
+      onWillUnmount(() => parent.render(true));
     }
   }
 
@@ -2507,15 +2504,11 @@ test("two renderings initiated between willPatch and patched", async () => {
     "Parent:rendered",
   ]).toBeLogged();
 
+  await nextMicroTick();
+  expect(["Panel:willRender", "Panel:rendered"]).toBeLogged();
+
   await nextTick();
-  expect([
+  expect(["Parent:willPatch", "Panel:willPatch", "Panel:patched", "Parent:patched"]).toBeLogged();
-    "Panel:willRender",
-    "Panel:rendered",
-    "Parent:willPatch",
-    "Panel:willPatch",
-    "Panel:patched",
-    "Parent:patched",
-  ]).toBeLogged();
   expect(fixture.innerHTML).toBe("<div><abc>Panel1Mounted</abc></div>");
 
   parent.state.panel = "Panel2";
@@ -2753,12 +2746,20 @@ test("delay willUpdateProps with rendering grandchild", async () => {
     static template = xml`<Parent state="state"/>`;
     static components = { Parent };
     state = { value: 0 };
+    setup() {
+      useLogLifecycle();
     }
+  }
+
   const parent = await mount(GrandParent, fixture);
   expect(fixture.innerHTML).toBe("0_0<div></div>");
   expect([
+    "GrandParent:setup",
+    "GrandParent:willStart",
+    "GrandParent:willRender",
     "Parent:setup",
     "Parent:willStart",
+    "GrandParent:rendered",
     "Parent:willRender",
     "DelayedChild:setup",
     "DelayedChild:willStart",
@@ -2772,20 +2773,23 @@ test("delay willUpdateProps with rendering grandchild", async () => {
     "ReactiveChild:mounted",
     "DelayedChild:mounted",
     "Parent:mounted",
+    "GrandParent:mounted",
   ]).toBeLogged();
 
   promise = makeDeferred();
   const prom1 = promise;
   parent.state.value = 1;
   child.render(); // trigger a root rendering first
-  parent.render();
+  parent.render(true);
   reactiveChild.render();
   await nextTick();
   expect(fixture.innerHTML).toBe("0_0<div></div>");
   expect([
     "DelayedChild:willRender",
     "DelayedChild:rendered",
+    "GrandParent:willRender",
     "Parent:willUpdateProps",
+    "GrandParent:rendered",
     "ReactiveChild:willRender",
     "ReactiveChild:rendered",
     "Parent:willRender",
@@ -2800,12 +2804,14 @@ test("delay willUpdateProps with rendering grandchild", async () => {
   const prom2 = promise;
   child.render(); // trigger a root rendering first
   parent.state.value = 2;
-  parent.render();
+  parent.render(true);
   reactiveChild.render();
   await nextTick();
   expect(fixture.innerHTML).toBe("0_0<div></div>");
   expect([
+    "GrandParent:willRender",
     "Parent:willUpdateProps",
+    "GrandParent:rendered",
     "ReactiveChild:willRender",
     "ReactiveChild:rendered",
     "Parent:willRender",
@@ -2822,12 +2828,14 @@ test("delay willUpdateProps with rendering grandchild", async () => {
   expect([
     "DelayedChild:willRender",
     "DelayedChild:rendered",
+    "GrandParent:willPatch",
     "Parent:willPatch",
     "ReactiveChild:willPatch",
     "DelayedChild:willPatch",
     "DelayedChild:patched",
     "ReactiveChild:patched",
     "Parent:patched",
+    "GrandParent:patched",
   ]).toBeLogged();
 
   prom1.resolve();

tests/components/hooks.test.ts

@@ -223,7 +223,7 @@ describe("hooks", () => {
     expect(fixture.innerHTML).toBe("<div>maggot brain</div>");
     someVal = "brain";
     someVal2 = "maggot";
-    component.render();
+    component.render(true);
     await nextTick();
     expect(fixture.innerHTML).toBe("<div>brain maggot</div>");
   });

tests/components/lifecycle.test.ts

@@ -849,8 +849,9 @@ describe("lifecycle hooks", () => {
 
     class Parent extends Component {
       static template = xml`
-        <Child />`;
+        <Child someValue="state.value" />`;
       static components = { Child };
+      state = useState({ value: 1 });
       setup() {
         useLogLifecycle();
       }
@@ -871,7 +872,7 @@ describe("lifecycle hooks", () => {
       "Parent:mounted",
     ]).toBeLogged();
 
-    parent.render(); // to block child render
+    parent.state.value++; // to block child render
     await nextTick();
     expect(["Parent:willRender", "Child:willUpdateProps", "Parent:rendered"]).toBeLogged();
 
@@ -1008,20 +1009,15 @@ describe("lifecycle hooks", () => {
     await nextTick();
     expect([
       "C:willRender",
-      "D:willUpdateProps",
       "F:setup",
       "F:willStart",
       "C:rendered",
-      "D:willRender",
-      "D:rendered",
       "F:willRender",
       "F:rendered",
       "C:willPatch",
-      "D:willPatch",
       "E:willUnmount",
       "E:willDestroy",
       "F:mounted",
-      "D:patched",
       "C:patched",
     ]).toBeLogged();
   });

tests/components/rendering.test.ts

@@ -0,0 +1,346 @@
+import { Component, mount, onRendered, onWillUpdateProps, useState, xml } from "../../src";
+import {
+  makeTestFixture,
+  snapshotEverything,
+  nextTick,
+  useLogLifecycle,
+  makeDeferred,
+} from "../helpers";
+
+let fixture: HTMLElement;
+
+snapshotEverything();
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+});
+
+describe("rendering semantics", () => {
+  test("can render a parent without rendering child", async () => {
+    class Child extends Component {
+      static template = xml`child`;
+      setup() {
+        useLogLifecycle();
+      }
+    }
+
+    class Parent extends Component {
+      static template = xml`
+        <t t-esc="state.value"/>
+        <Child/>
+      `;
+      static components = { Child };
+
+      state = useState({ value: "A" });
+      setup() {
+        useLogLifecycle();
+      }
+    }
+
+    const parent = await mount(Parent, fixture);
+
+    expect(fixture.innerHTML).toBe("Achild");
+    expect([
+      "Parent:setup",
+      "Parent:willStart",
+      "Parent:willRender",
+      "Child:setup",
+      "Child:willStart",
+      "Parent:rendered",
+      "Child:willRender",
+      "Child:rendered",
+      "Child:mounted",
+      "Parent:mounted",
+    ]).toBeLogged();
+
+    parent.state.value = "B";
+    await nextTick();
+    expect(fixture.innerHTML).toBe("Bchild");
+    expect([
+      "Parent:willRender",
+      "Parent:rendered",
+      "Parent:willPatch",
+      "Parent:patched",
+    ]).toBeLogged();
+  });
+
+  test("can force a render to update sub tree", async () => {
+    let childN = 0;
+    let parentN = 0;
+    class Child extends Component {
+      static template = xml`child`;
+      setup() {
+        onRendered(() => childN++);
+      }
+    }
+
+    class Parent extends Component {
+      static template = xml`
+        <t t-esc="state.value"/>
+        <Child/>
+      `;
+      static components = { Child };
+
+      state = { value: "A" };
+      setup() {
+        onRendered(() => parentN++);
+      }
+    }
+
+    const parent = await mount(Parent, fixture);
+
+    expect(fixture.innerHTML).toBe("Achild");
+    expect(parentN).toBe(1);
+    expect(childN).toBe(1);
+
+    parent.state.value = "B";
+    parent.render(true);
+    await nextTick();
+    expect(fixture.innerHTML).toBe("Bchild");
+    expect(parentN).toBe(2);
+    expect(childN).toBe(2);
+  });
+
+  test("props are reactive", async () => {
+    class Child extends Component {
+      static template = xml`<t t-esc="props.a.b"/>`;
+      setup() {
+        useLogLifecycle();
+      }
+    }
+
+    class Parent extends Component {
+      static template = xml`
+        <Child a="state"/>
+      `;
+      static components = { Child };
+
+      state = useState({ b: 1 });
+      setup() {
+        useLogLifecycle();
+      }
+    }
+
+    const parent = await mount(Parent, fixture);
+    expect(fixture.innerHTML).toBe("1");
+    expect([
+      "Parent:setup",
+      "Parent:willStart",
+      "Parent:willRender",
+      "Child:setup",
+      "Child:willStart",
+      "Parent:rendered",
+      "Child:willRender",
+      "Child:rendered",
+      "Child:mounted",
+      "Parent:mounted",
+    ]).toBeLogged();
+
+    parent.state.b = 3;
+    await nextTick();
+    expect(fixture.innerHTML).toBe("3");
+    expect(["Child:willRender", "Child:rendered", "Child:willPatch", "Child:patched"]).toBeLogged();
+  });
+
+  test("props are reactive (nested prop)", async () => {
+    class Child extends Component {
+      static template = xml`<t t-esc="props.a.b.c"/>`;
+
+      setup() {
+        useLogLifecycle();
+      }
+    }
+
+    class Parent extends Component {
+      static template = xml`
+        <Child a="state"/>
+      `;
+      static components = { Child };
+
+      state = useState({ b: { c: 1 } });
+
+      setup() {
+        useLogLifecycle();
+      }
+    }
+
+    const parent = await mount(Parent, fixture);
+    expect(fixture.innerHTML).toBe("1");
+    expect([
+      "Parent:setup",
+      "Parent:willStart",
+      "Parent:willRender",
+      "Child:setup",
+      "Child:willStart",
+      "Parent:rendered",
+      "Child:willRender",
+      "Child:rendered",
+      "Child:mounted",
+      "Parent:mounted",
+    ]).toBeLogged();
+
+    parent.state.b.c = 3; // parent is now subscribed to 'b' key
+    await nextTick();
+    expect(fixture.innerHTML).toBe("3");
+    expect(["Child:willRender", "Child:rendered", "Child:willPatch", "Child:patched"]).toBeLogged();
+
+    parent.state.b = { c: 444 }; // triggers a parent and a child render
+    await nextTick();
+    expect(fixture.innerHTML).toBe("444");
+    expect([
+      "Parent:willRender",
+      "Parent:rendered",
+      "Child:willRender",
+      "Child:rendered",
+      "Parent:willPatch",
+      "Parent:patched",
+      "Child:willPatch",
+      "Child:patched",
+    ]).toBeLogged();
+  });
+
+  test("rendering is atomic (for one subtree)", async () => {
+    const def = makeDeferred();
+
+    class C extends Component {
+      static template = xml`<t t-esc="props.obj.val"/>`;
+
+      setup() {
+        useLogLifecycle();
+      }
+    }
+
+    class B extends Component {
+      static template = xml`<C obj="props.obj"/>`;
+      static components = { C };
+
+      setup() {
+        useLogLifecycle();
+        onWillUpdateProps(() => def);
+      }
+    }
+
+    class A extends Component {
+      static template = xml`<t t-esc="state.obj.val"/><B obj="state.obj"/>`;
+      static components = { B };
+
+      state = useState({ obj: { val: 1 } });
+
+      setup() {
+        useLogLifecycle();
+      }
+    }
+
+    const parent = await mount(A, fixture);
+    expect(fixture.innerHTML).toBe("11");
+    expect([
+      "A:setup",
+      "A:willStart",
+      "A:willRender",
+      "B:setup",
+      "B:willStart",
+      "A:rendered",
+      "B:willRender",
+      "C:setup",
+      "C:willStart",
+      "B:rendered",
+      "C:willRender",
+      "C:rendered",
+      "C:mounted",
+      "B:mounted",
+      "A:mounted",
+    ]).toBeLogged();
+
+    parent.state.obj.val = 3;
+    await nextTick();
+    expect(fixture.innerHTML).toBe("33");
+    expect([
+      "A:willRender",
+      "A:rendered",
+      "C:willRender",
+      "C:rendered",
+      "A:willPatch",
+      "A:patched",
+      "C:willPatch",
+      "C:patched",
+    ]).toBeLogged();
+
+    def.resolve();
+    await nextTick();
+    expect([]).toBeLogged();
+  });
+});
+
+test("force render in case of existing render", async () => {
+  const def = makeDeferred();
+
+  class C extends Component {
+    static template = xml`C`;
+    setup() {
+      useLogLifecycle();
+    }
+  }
+  class B extends Component {
+    static template = xml`<C/><t t-esc="props.val"/>`;
+    static components = { C };
+    setup() {
+      useLogLifecycle();
+      onWillUpdateProps(() => def);
+    }
+  }
+  class A extends Component {
+    static template = xml`<B val="state.val"/>`;
+    static components = { B };
+    state = useState({ val: 1 });
+    setup() {
+      useLogLifecycle();
+    }
+  }
+  const parent = await mount(A, fixture);
+  expect(fixture.innerHTML).toBe("C1");
+  expect([
+    "A:setup",
+    "A:willStart",
+    "A:willRender",
+    "B:setup",
+    "B:willStart",
+    "A:rendered",
+    "B:willRender",
+    "C:setup",
+    "C:willStart",
+    "B:rendered",
+    "C:willRender",
+    "C:rendered",
+    "C:mounted",
+    "B:mounted",
+    "A:mounted",
+  ]).toBeLogged();
+
+  // trigger a new rendering, blocked in B
+  parent.state.val = 2;
+  await nextTick();
+  expect(["A:willRender", "B:willUpdateProps", "A:rendered"]).toBeLogged();
+
+  // initiate a new render with force=true. it should cancel the current render
+  // and also be blocked in B
+  parent.render(true);
+  await nextTick();
+  expect(["A:willRender", "B:willUpdateProps", "A:rendered"]).toBeLogged();
+
+  def.resolve();
+  await nextTick();
+  // we check here that the render reaches C (so, that it was properly forced)
+  expect([
+    "B:willRender",
+    "C:willUpdateProps",
+    "B:rendered",
+    "C:willRender",
+    "C:rendered",
+    "A:willPatch",
+    "B:willPatch",
+    "C:willPatch",
+    "C:patched",
+    "B:patched",
+    "A:patched",
+  ]).toBeLogged();
+});

tests/components/t_props.test.ts

@@ -65,7 +65,7 @@ describe("t-props", () => {
         `;
       setup() {
         expect(this.props).toEqual({ a: 1, b: 2 });
-        expect(this.props).toBe(props);
+        expect(this.props).not.toBe(props);
       }
     }
     class Parent extends Component {

tests/reactivity.test.ts

@@ -1612,7 +1612,7 @@ describe("Reactivity: useState", () => {
     expect([...steps]).toEqual(["list"]);
     await nextTick();
     expect(fixture.innerHTML).toBe("<div><div>3</div> Total: 3 Count: 1</div>");
-    expect([...steps]).toEqual(["list", "quantity1"]);
+    expect([...steps]).toEqual(["list"]);
     steps.clear();
 
     secondQuantity.quantity = 2;