support using object variables in t-esc

src/qweb.ts

@@ -469,7 +469,7 @@ export class QWeb {
       // dynamic attributes
       if (name.startsWith("t-att-")) {
         let attName = name.slice(6);
-        let formattedValue = this._formatExpression(ctx.getValue(value!));
+        let formattedValue = this._formatExpression(ctx.getValue(value!), ctx);
         const attID = ctx.generateID();
         if (!attName.match(/^[a-zA-Z]+$/)) {
           // attribute contains 'non letters' => we want to quote it

tests/__snapshots__/qweb.test.ts.snap

@@ -99,6 +99,20 @@ exports[`attributes format value 1`] = `
 }"
 `;
 
+exports[`attributes from object variables set previously 1`] = `
+"function anonymous(context,extra
+) {
+    let h = this.utils.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    let _2 = {a:'b'}.a;
+    let c3 = [], p3 = {key:3,attrs:{class: _2}};
+    let vn3 = h('span', p3, c3);
+    c1.push(vn3);
+    return vn1;
+}"
+`;
+
 exports[`attributes from variables set previously 1`] = `
 "function anonymous(context,extra
 ) {

tests/qweb.test.ts

@@ -410,14 +410,11 @@ describe("attributes", () => {
     expect(result).toBe('<div><span class="def"></span></div>');
   });
 
-  test.skip("from object variables set previously", () => {
-    // qweb is stupid and does not support this.
-    // To do that properly, we need to extend the formatExpression method to
-    // be able to deal with objects.  I think that it is not easy:
-    // it should properly deal with stuff like {a:expr, b: {c: otherexpr}}
+  test("from object variables set previously", () => {
+    // Note: standard qweb does not allow this...
     qweb.addTemplate(
       "test",
-      `<div t-debug="1"><t t-set="o" t-value="{a:'b'}"/><span t-att-class="o.a"/></div>`
+      `<div><t t-set="o" t-value="{a:'b'}"/><span t-att-class="o.a"/></div>`
     );
     const result = renderToString(qweb, "test");
     expect(result).toBe('<div><span class="b"></span></div>');