[FIX] mail: guard the thread name and test the fallback

task-2343800

closes odoo/odoo#58848

X-original-commit: 13d78eda1243a5a625473adbae981b2891221ffc
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/mail/static/src/components/composer/composer.xml

@@ -38,7 +38,7 @@
                                 <b class="text-muted">To: </b>
                                 <em class="text-muted">Followers of </em>
                                 <b>
-                                    <t t-if="composer.thread">
+                                    <t t-if="composer.thread and composer.thread.name">
                                         &#32;&quot;<t t-esc="composer.thread.name"/>&quot;
                                     </t>
                                     <t t-else="">

addons/mail/static/src/components/composer/composer_tests.js

@@ -1842,6 +1842,23 @@ QUnit.test('remove an uploading attachment aborts upload', async function (asser
     });
 });
 
+QUnit.test("basic rendering when sending a message to the followers and thread doesn't have a name", async function (assert) {
+    assert.expect(1);
+
+    await this.start();
+    const thread = this.env.models['mail.thread'].create({
+        composer: [['create', { isLog: false }]],
+        id: 20,
+        model: 'res.partner',
+    });
+    await this.createComposerComponent(thread.composer, { hasFollowers: true });
+    assert.strictEqual(
+        document.querySelector('.o_Composer_followers').textContent.replace(/\s+/g, ''),
+        "To:Followersofthisdocument",
+        "Composer should display \"To: Followers of this document\" if the thread as no name."
+    );
+});
+
 });
 });
 });