[FIX] qweb: correctly capture the scope of arrow functions in props

src/component/directive.ts

@@ -234,7 +234,11 @@ QWeb.addDirective({
       } else if (!name.startsWith("t-")) {
         if (name !== "class" && name !== "style") {
           // this is a prop!
-          props[name] = ctx.formatExpression(value) || "undefined";
+          if (value.includes("=>")) {
+            props[name] = ctx.captureExpression(value);
+          } else {
+            props[name] = ctx.formatExpression(value) || "undefined";
+          }
         }
       }
     }

src/qweb/compilation_context.ts

@@ -163,7 +163,18 @@ export class CompilationContext {
     const done = new Set();
     return tokens
       .map((tok) => {
-        if (tok.varName) {
+        // "this" in captured expressions should be the current component
+        if (tok.value === "this") {
+          if (!done.has("this")) {
+            done.add("this");
+            this.addLine(`const this_${argId} = utils.getComponent(context);`);
+          }
+          tok.value = `this_${argId}`;
+        }
+        // Variables that should be looked up in the scope. isLocal is for arrow
+        // function arguments that should stay untouched (eg "ev => ev" should
+        // not become "const ev_1 = scope['ev']; ev_1 => ev_1")
+        if (tok.varName && !tok.isLocal) {
           if (!done.has(tok.varName)) {
             done.add(tok.varName);
             this.addLine(`const ${tok.varName}_${argId} = ${tok.value};`);

src/qweb/expression_parser.ts

@@ -70,6 +70,7 @@ interface Token {
   size?: number;
   varName?: string;
   replace?: Function;
+  isLocal?: boolean;
 }
 
 const STATIC_TOKEN_MAP: { [key: string]: TKind } = Object.assign(Object.create(null), {
@@ -254,6 +255,7 @@ const isRightSeparator = (token) =>
  * the list of variables so it does not get replaced by a lookup in the context
  */
 export function compileExprToArray(expr: string, scope: { [key: string]: QWebVar }): Token[] {
+  const localVars = new Set<string>();
   scope = Object.create(scope);
   const tokens = tokenize(expr);
 
@@ -308,11 +310,13 @@ export function compileExprToArray(expr: string, scope: { [key: string]: QWebVar
           if (tokens[j].type === "SYMBOL" && tokens[j].originalValue) {
             tokens[j].value = tokens[j].originalValue!;
             scope[tokens[j].value] = { id: tokens[j].value, expr: tokens[j].value };
+            localVars.add(tokens[j].value);
           }
           j--;
         }
       } else {
         scope[token.value] = { id: token.value, expr: token.value };
+        localVars.add(token.value);
       }
     }
 
@@ -327,6 +331,13 @@ export function compileExprToArray(expr: string, scope: { [key: string]: QWebVar
     }
     i++;
   }
+  // Mark all variables that have been used locally.
+  // This assumes the expression has only one scope (incorrect but "good enough for now")
+  for (const token of tokens) {
+    if (token.type === "SYMBOL" && localVars.has(token.value)) {
+      token.isLocal = true;
+    }
+  }
   return tokens;
 }
 

tests/component/__snapshots__/component.test.ts.snap

@@ -1454,6 +1454,350 @@ exports[`other directives with t-component t-set outside modified in t-foreach 1
 }"
 `;
 
+exports[`props evaluation  arrow function prop captures component instance as 'this' 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Parent\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    // Component 'Child'
+    const this_2 = utils.getComponent(context);
+    let w3 = '__4__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__4__']] : false;
+    let props3 = {callback:value=>this_2.setValue(value),value:scope['state'].val};
+    if (w3 && w3.__owl__.currentFiber && !w3.__owl__.vnode) {
+        w3.destroy();
+        w3 = false;
+    }
+    if (w3) {
+        w3.__updateProps(props3, extra.fiber, undefined);
+        let pvnode = w3.__owl__.pvnode;
+        c1.push(pvnode);
+    } else {
+        let componentKey3 = \`Child\`;
+        let W3 = scope['Child'] || context.constructor.components[componentKey3] || QWeb.components[componentKey3];
+        if (!W3) {throw new Error('Cannot find the definition of component \\"' + componentKey3 + '\\"')}
+        w3 = new W3(parent, props3);
+        parent.__owl__.cmap['__4__'] = w3.__owl__.id;
+        let fiber = w3.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+        let pvnode = h('dummy', {key: '__4__', hook: {remove() {},destroy(vn) {w3.destroy();}}});
+        c1.push(pvnode);
+        w3.__owl__.pvnode = pvnode;
+    }
+    w3.__owl__.parentLastFiberId = extra.fiber.id;
+    return vn1;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures component instance as 'this' 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Child\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c5 = [], p5 = {key:5};
+    let vn5 = h('span', p5, c5);
+    let _6 = scope['props'].value;
+    if (_6 != null) {
+        c5.push({text: _6});
+    }
+    return vn5;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures context component instance as 'this' inside slot 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Parent\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    // Component 'Wrapper'
+    let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+    let props2 = {};
+    if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+        w2.destroy();
+        w2 = false;
+    }
+    if (w2) {
+        w2.__updateProps(props2, extra.fiber, utils.combine(context, scope));
+        let pvnode = w2.__owl__.pvnode;
+        c1.push(pvnode);
+    } else {
+        let componentKey2 = \`Wrapper\`;
+        let W2 = scope['Wrapper'] || context.constructor.components[componentKey2] || QWeb.components[componentKey2];
+        if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+        w2 = new W2(parent, props2);
+        parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+        w2.__owl__.slotId = 1;
+        let fiber = w2.__prepare(extra.fiber, utils.combine(context, scope), () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+        let pvnode = h('dummy', {key: '__3__', hook: {remove() {},destroy(vn) {w2.destroy();}}});
+        c1.push(pvnode);
+        w2.__owl__.pvnode = pvnode;
+    }
+    w2.__owl__.parentLastFiberId = extra.fiber.id;
+    return vn1;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures context component instance as 'this' inside slot 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Wrapper\\"
+    let utils = this.constructor.utils;
+    let result;
+    let h = this.h;
+    const slot8 = this.constructor.slots[context.__owl__.slotId + '_' + 'default'];
+    if (slot8) {
+        let children9= []
+        result = {}
+        slot8.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: children9, parent: extra.parent || context}));
+        utils.defineProxy(result, children9[0]);
+    }
+    return result;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures context component instance as 'this' inside slot 3`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_default_template\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = extra.parent;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c4 = extra.parentNode;
+    // Component 'Child'
+    const this_5 = utils.getComponent(context);
+    let w6 = '__7__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__7__']] : false;
+    let props6 = {callback:value=>this_5.setValue(value),value:scope['state'].val};
+    if (w6 && w6.__owl__.currentFiber && !w6.__owl__.vnode) {
+        w6.destroy();
+        w6 = false;
+    }
+    if (w6) {
+        w6.__updateProps(props6, extra.fiber, undefined);
+        let pvnode = w6.__owl__.pvnode;
+        c4.push(pvnode);
+    } else {
+        let componentKey6 = \`Child\`;
+        let W6 = scope['Child'] || context.constructor.components[componentKey6] || QWeb.components[componentKey6];
+        if (!W6) {throw new Error('Cannot find the definition of component \\"' + componentKey6 + '\\"')}
+        w6 = new W6(parent, props6);
+        parent.__owl__.cmap['__7__'] = w6.__owl__.id;
+        let fiber = w6.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+        let pvnode = h('dummy', {key: '__7__', hook: {remove() {},destroy(vn) {w6.destroy();}}});
+        c4.push(pvnode);
+        w6.__owl__.pvnode = pvnode;
+    }
+    w6.__owl__.parentLastFiberId = extra.fiber.id;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures context component instance as 'this' inside slot 4`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Child\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c10 = [], p10 = {key:10};
+    let vn10 = h('span', p10, c10);
+    let _11 = scope['props'].value;
+    if (_11 != null) {
+        c10.push({text: _11});
+    }
+    return vn10;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures context component instance as 'this' inside slot default content 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Parent\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    // Component 'Wrapper'
+    let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+    let props2 = {};
+    if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+        w2.destroy();
+        w2 = false;
+    }
+    if (w2) {
+        w2.__updateProps(props2, extra.fiber, undefined);
+        let pvnode = w2.__owl__.pvnode;
+        c1.push(pvnode);
+    } else {
+        let componentKey2 = \`Wrapper\`;
+        let W2 = scope['Wrapper'] || context.constructor.components[componentKey2] || QWeb.components[componentKey2];
+        if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+        w2 = new W2(parent, props2);
+        parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+        let fiber = w2.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+        let pvnode = h('dummy', {key: '__3__', hook: {remove() {},destroy(vn) {w2.destroy();}}});
+        c1.push(pvnode);
+        w2.__owl__.pvnode = pvnode;
+    }
+    w2.__owl__.parentLastFiberId = extra.fiber.id;
+    return vn1;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures context component instance as 'this' inside slot default content 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Wrapper\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let result;
+    let h = this.h;
+    const slot4 = this.constructor.slots[context.__owl__.slotId + '_' + 'default'];
+    if (slot4) {
+        let children5= []
+        result = {}
+        slot4.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: children5, parent: extra.parent || context}));
+        utils.defineProxy(result, children5[0]);
+    } else {
+        // Component 'Child'
+        const this_6 = utils.getComponent(context);
+        let w7 = '__8__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__8__']] : false;
+        let vn9 = {};
+        result = vn9;
+        let props7 = {callback:value=>this_6.setValue(value),value:scope['state'].val};
+        if (w7 && w7.__owl__.currentFiber && !w7.__owl__.vnode) {
+            w7.destroy();
+            w7 = false;
+        }
+        if (w7) {
+            w7.__updateProps(props7, extra.fiber, undefined);
+            let pvnode = w7.__owl__.pvnode;
+            utils.defineProxy(vn9, pvnode);
+        } else {
+            let componentKey7 = \`Child\`;
+            let W7 = scope['Child'] || context.constructor.components[componentKey7] || QWeb.components[componentKey7];
+            if (!W7) {throw new Error('Cannot find the definition of component \\"' + componentKey7 + '\\"')}
+            w7 = new W7(parent, props7);
+            parent.__owl__.cmap['__8__'] = w7.__owl__.id;
+            let fiber = w7.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+            let pvnode = h('dummy', {key: '__8__', hook: {remove() {},destroy(vn) {w7.destroy();}}});
+            utils.defineProxy(vn9, pvnode);
+            w7.__owl__.pvnode = pvnode;
+        }
+        w7.__owl__.parentLastFiberId = extra.fiber.id;
+    }
+    return result;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures context component instance as 'this' inside slot default content 3`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Child\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c10 = [], p10 = {key:10};
+    let vn10 = h('span', p10, c10);
+    let _11 = scope['props'].value;
+    if (_11 != null) {
+        c10.push({text: _11});
+    }
+    return vn10;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures loop variables 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Parent\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    let _2 = [0,1];
+    if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
+    let _3 = _2;
+    let _4 = _2;
+    if (!(_2 instanceof Array)) {
+        _3 = Object.keys(_2);
+        _4 = Object.values(_2);
+    }
+    let _length3 = _3.length;
+    let _origScope5 = scope;
+    scope = Object.create(scope);
+    for (let i1 = 0; i1 < _length3; i1++) {
+        scope.loopVar_first = i1 === 0
+        scope.loopVar_last = i1 === _length3 - 1
+        scope.loopVar_index = i1
+        scope.loopVar = _3[i1]
+        scope.loopVar_value = _4[i1]
+        let key1 = scope['loopVar'];
+        // Component 'Child'
+        const this_6 = utils.getComponent(context);
+        const loopVar_6 = scope['loopVar'];
+        let k8 = \`__8__\${key1}__\`;
+        let w7 = k8 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[k8]] : false;
+        let props7 = {callback:()=>this_6.setValue(loopVar_6),value:scope['state'].val};
+        if (w7 && w7.__owl__.currentFiber && !w7.__owl__.vnode) {
+            w7.destroy();
+            w7 = false;
+        }
+        if (w7) {
+            w7.__updateProps(props7, extra.fiber, undefined);
+            let pvnode = w7.__owl__.pvnode;
+            c1.push(pvnode);
+        } else {
+            let componentKey7 = \`Child\`;
+            let W7 = scope['Child'] || context.constructor.components[componentKey7] || QWeb.components[componentKey7];
+            if (!W7) {throw new Error('Cannot find the definition of component \\"' + componentKey7 + '\\"')}
+            w7 = new W7(parent, props7);
+            parent.__owl__.cmap[k8] = w7.__owl__.id;
+            let fiber = w7.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+            let pvnode = h('dummy', {key: k8, hook: {remove() {},destroy(vn) {w7.destroy();}}});
+            c1.push(pvnode);
+            w7.__owl__.pvnode = pvnode;
+        }
+        w7.__owl__.parentLastFiberId = extra.fiber.id;
+    }
+    scope = _origScope5;
+    return vn1;
+}"
+`;
+
+exports[`props evaluation  arrow function prop captures loop variables 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Child\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c9 = [], p9 = {key:9};
+    let vn9 = h('span', p9, c9);
+    let _10 = scope['props'].value;
+    if (_10 != null) {
+        c9.push({text: _10});
+    }
+    return vn9;
+}"
+`;
+
 exports[`props evaluation  t-set with a body expression can be used as textual prop 1`] = `
 "function anonymous(context, extra
 ) {

tests/component/component.test.ts

@@ -1881,6 +1881,176 @@ describe("props evaluation ", () => {
     await widget.mount(fixture);
     expect(fixture.innerHTML).toBe("<div><span>&lt;p&gt;4343&lt;/p&gt;<p>43</p></span></div>");
   });
+
+  test("arrow function prop captures component instance as 'this'", async () => {
+    expect.assertions(5);
+    let child, parent;
+    class Child extends Component {
+      setup() {
+        child = this;
+      }
+    }
+    env.qweb.addTemplate("Child", `<span><t t-esc="props.value"/></span>`);
+
+    class Parent extends Component {
+      static components = { Child };
+      state = useState({ val: 42 });
+      setup() {
+        parent = this;
+      }
+      setValue(value) {
+        expect(this).toBe(parent);
+        this.state.val = value;
+      }
+    }
+    env.qweb.addTemplate(
+      "Parent",
+      `<div>
+        <Child callback="value => this.setValue(value)" value="state.val"/>
+      </div>`
+    );
+
+    const widget = new Parent();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><span>42</span></div>");
+    child.props.callback(123);
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><span>123</span></div>");
+    expect(env.qweb.templates.Parent.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.Child.fn.toString()).toMatchSnapshot();
+  });
+
+  test("arrow function prop captures context component instance as 'this' inside slot", async () => {
+    expect.assertions(7);
+    let child, parent;
+    class Child extends Component {
+      setup() {
+        child = this;
+      }
+    }
+    env.qweb.addTemplate("Child", `<span><t t-esc="props.value"/></span>`);
+
+    class Wrapper extends Component {}
+    env.qweb.addTemplate("Wrapper", `<t t-slot="default"/>`);
+
+    class Parent extends Component {
+      static components = { Child, Wrapper };
+      state = useState({ val: 42 });
+      setup() {
+        parent = this;
+      }
+      setValue(value) {
+        expect(this).toBe(parent);
+        this.state.val = value;
+      }
+    }
+    env.qweb.addTemplate(
+      "Parent",
+      `<div>
+        <Wrapper>
+          <Child callback="value => this.setValue(value)" value="state.val"/>
+        </Wrapper>
+      </div>`
+    );
+
+    const widget = new Parent();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><span>42</span></div>");
+    child.props.callback(123);
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><span>123</span></div>");
+    expect(env.qweb.templates.Parent.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.Wrapper.fn.toString()).toMatchSnapshot();
+    expect(QWeb.slots["1_default"].toString()).toMatchSnapshot();
+    expect(env.qweb.templates.Child.fn.toString()).toMatchSnapshot();
+  });
+
+  test("arrow function prop captures context component instance as 'this' inside slot default content", async () => {
+    expect.assertions(6);
+    let child, wrapper;
+    class Child extends Component {
+      setup() {
+        child = this;
+      }
+    }
+    env.qweb.addTemplate("Child", `<span><t t-esc="props.value"/></span>`);
+
+    class Wrapper extends Component {
+      static components = { Child };
+      state = useState({ val: 42 });
+      setup() {
+        wrapper = this;
+      }
+      setValue(value) {
+        expect(this).toBe(wrapper);
+        this.state.val = value;
+      }
+    }
+    env.qweb.addTemplate(
+      "Wrapper",
+      `<t t-slot="default">
+        <Child callback="value => this.setValue(value)" value="state.val"/>
+      </t>`
+    );
+
+    class Parent extends Component {
+      static components = { Wrapper };
+    }
+    env.qweb.addTemplate(
+      "Parent",
+      `<div>
+        <Wrapper/>
+      </div>`
+    );
+
+    const widget = new Parent();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><span>42</span></div>");
+    child.props.callback(123);
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><span>123</span></div>");
+    expect(env.qweb.templates.Parent.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.Wrapper.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.Child.fn.toString()).toMatchSnapshot();
+  });
+
+  test("arrow function prop captures loop variables", async () => {
+    let children = [];
+    class Child extends Component {
+      setup() {
+        children.push(this);
+      }
+    }
+    env.qweb.addTemplate("Child", `<span><t t-esc="props.value"/></span>`);
+
+    class Parent extends Component {
+      static components = { Child };
+      state = useState({ val: 42 });
+      setValue(value) {
+        this.state.val = value;
+      }
+    }
+    env.qweb.addTemplate(
+      "Parent",
+      `<div>
+        <t t-foreach="[0, 1]" t-as="loopVar" t-key="loopVar">
+          <Child callback="() => this.setValue(loopVar)" value="state.val"/>
+        </t>
+      </div>`
+    );
+
+    const widget = new Parent();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><span>42</span><span>42</span></div>");
+    children[0].props.callback();
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><span>0</span><span>0</span></div>");
+    children[1].props.callback();
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><span>1</span><span>1</span></div>");
+    expect(env.qweb.templates.Parent.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.Child.fn.toString()).toMatchSnapshot();
+  });
 });
 
 describe("other directives with t-component", () => {