[FIX] web: handle empty notebooks in form views

Before this commit, when re-activating a previously active notebook tab, the form
renderer would assume that a tab was actually active. However this does not happen
if no tab is visible or defined and it results in a crash instead.

Now, if no active tab is found, a default active tab (0 = first) is set. This only
helps to prevent the crash and does not affect the current behaviour.

closes odoo/odoo#50006

X-original-commit: 73e0c0a1395ebd0e2b4ac7f857c863a0358c5e17
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>
Signed-off-by: Julien Mougenot (jum) <jum@odoo.com>

2 files changed, 76 insertions, 2 deletions

diff --git a/addons/web/static/src/js/views/form/form_renderer.js b/addons/web/static/src/js/views/form/form_renderer.js
index 08819f79f57..1b672bdee19 100644
--- a/addons/web/static/src/js/views/form/form_renderer.js
+++ b/addons/web/static/src/js/views/form/form_renderer.js
@@ -213,9 +213,9 @@ var FormRenderer = BasicRenderer.extend({
         for (const notebook of this.el.querySelectorAll(':scope div.o_notebook')) {
             const name = notebook.dataset.name;
             const navs = notebook.querySelectorAll(':scope .o_notebook_headers .nav-item > .nav-link');
-            state[name] = [...navs].findIndex(
+            state[name] = Math.max([...navs].findIndex(
                 nav => nav.classList.contains('active')
-            );
+            ), 0);
         }
         return state;
     },
@@ -247,6 +247,9 @@ var FormRenderer = BasicRenderer.extend({
                 // We can't base the amount on the 'navs' length since some overrides
                 // are adding pageless nav items.
                 const validTabsAmount = pages.length;
+                if (!validTabsAmount) {
+                    continue; // No page defined on the notebook.
+                }
                 let activeIndex = state[name];
                 if (navs[activeIndex].classList.contains('o_invisible_modifier')) {
                     activeIndex = [...navs].findIndex(
diff --git a/addons/web/static/tests/views/form_tests.js b/addons/web/static/tests/views/form_tests.js
index e9d1903c14d..def58359e2f 100644
--- a/addons/web/static/tests/views/form_tests.js
+++ b/addons/web/static/tests/views/form_tests.js
@@ -712,6 +712,77 @@ QUnit.module('Views', {
         form.destroy();
     });
 
+    QUnit.test('empty notebook', async function (assert) {
+        assert.expect(2);
+
+        const form = await createView({
+            arch: `
+                <form string="Partners">
+                    <sheet>
+                        <notebook/>
+                    </sheet>
+                </form>`,
+            data: this.data,
+            model: 'partner',
+            res_id: 1,
+            View: FormView,
+        });
+
+        // Does not change when switching state
+        await testUtils.form.clickEdit(form);
+
+        assert.containsNone(form, ':scope .o_notebook .nav');
+
+        // Does not change when coming back to initial state
+        await testUtils.form.clickSave(form);
+
+        assert.containsNone(form, ':scope .o_notebook .nav');
+
+        form.destroy();
+    });
+
+    QUnit.test('no visible page', async function (assert) {
+        assert.expect(4);
+
+        const form = await createView({
+            arch: `
+                <form string="Partners">
+                    <sheet>
+                        <notebook>
+                            <page string="Foo" invisible="1">
+                                <field name="foo"/>
+                            </page>
+                            <page string="Bar" invisible="1">
+                                <field name="bar"/>
+                            </page>
+                        </notebook>
+                    </sheet>
+                </form>`,
+            data: this.data,
+            model: 'partner',
+            res_id: 1,
+            View: FormView,
+        });
+
+        // Does not change when switching state
+        await testUtils.form.clickEdit(form);
+
+        for (const nav of form.el.querySelectorAll(':scope .o_notebook .nav')) {
+            assert.containsNone(nav, '.nav-link.active');
+            assert.containsN(nav, '.nav-item.o_invisible_modifier', 2);
+        }
+
+        // Does not change when coming back to initial state
+        await testUtils.form.clickSave(form);
+
+        for (const nav of form.el.querySelectorAll(':scope .o_notebook .nav')) {
+            assert.containsNone(nav, '.nav-link.active');
+            assert.containsN(nav, '.nav-item.o_invisible_modifier', 2);
+        }
+
+        form.destroy();
+    });
+
     QUnit.test('invisible attrs on first notebook page', async function (assert) {
         assert.expect(6);