[IMP] mail: make composer mixin take lang from template

Mail composer mixin already synchronizes subject and body based on a mail
template, easing calling rendering methods available through mail render
mixin.

In this commit we add the same mechanism on lang. Lang is taken from the
template and can be used to render content based on language defined on
template, generally based on a customer.

Some query counters are updated, without being sure those are really coming
from this commit. Anyway they will be updated in batch at the end of this
PR, as tracking them on each commit is tedious and not always really
useful.

Task-3046371 (Mail: Better Language Support in Composer)

Part-of: odoo/odoo#106177

addons/mail/models/mail_composer_mixin.py

@@ -26,6 +26,8 @@ class MailComposerMixin(models.AbstractModel):
         'Contents', compute='_compute_body', readonly=False, store=True,
         render_engine='qweb', render_options={'post_process': True}, sanitize=False)
     template_id = fields.Many2one('mail.template', 'Mail Template', domain="[('model', '=', render_model)]")
+    # Language: override mail.render.mixin field, copy template value
+    lang = fields.Char(compute='_compute_lang', precompute=True, readonly=False, store=True)
     # Access
     is_mail_template_editor = fields.Boolean('Is Editor', compute='_compute_is_mail_template_editor')
     can_edit_body = fields.Boolean('Can Edit Body', compute='_compute_can_edit_body')
@@ -46,6 +48,16 @@ class MailComposerMixin(models.AbstractModel):
             elif not composer_mixin.body:
                 composer_mixin.body = False
 
+    @api.depends('template_id')
+    def _compute_lang(self):
+        for composer_mixin in self:
+            """ Take value form template when set. When removing the template
+            reset the value to avoid keeping part of template configuration. """
+            if composer_mixin.template_id.lang:
+                composer_mixin.lang = composer_mixin.template_id.lang
+            elif not composer_mixin.template_id:
+                composer_mixin.lang = False
+
     @api.depends_context('uid')
     def _compute_is_mail_template_editor(self):
         is_mail_template_editor = self.env.is_admin() or self.env.user.has_group('mail.group_mail_template_editor')

addons/test_mail/tests/test_mail_composer_mixin.py

@@ -47,8 +47,8 @@ class TestMailComposerMixin(TestMailCommon, TestRecipients):
             'source_ids': [(4, source.id)],
         })
         self.assertEqual(composer.body, self.mail_template.body_html)
+        self.assertEqual(composer.lang, self.mail_template.lang)
         self.assertEqual(composer.subject, self.mail_template.subject)
-        self.assertFalse(composer.lang, 'Fixme: lang is not propagated currently')
 
         subject = composer._render_field('subject', source.ids)[source.id]
         self.assertEqual(subject, f'EnglishSubject for {source.name}')
@@ -84,7 +84,6 @@ class TestMailComposerMixin(TestMailCommon, TestRecipients):
         source = self.test_record.with_env(self.env)
         composer = self.env['mail.test.composer.mixin'].create({
             'description': '<p>Description for <t t-esc="object.name"/></p>',
-            'lang': '{{ object.customer_id.lang }}',
             'name': 'Invite',
             'template_id': self.mail_template.id,
             'source_ids': [(4, source.id)],

addons/test_mail/tests/test_performance.py

@@ -338,7 +338,7 @@ class TestMailAPIPerformance(BaseMailPerformance):
     def test_mail_composer(self):
         test_record, _test_template = self._create_test_records()
         customer_id = self.customer.id
-        with self.assertQueryCount(admin=3, employee=3):
+        with self.assertQueryCount(admin=4, employee=4):
             composer = self.env['mail.compose.message'].with_context({
                 'default_composition_mode': 'comment',
                 'default_model': test_record._name,
@@ -348,7 +348,7 @@ class TestMailAPIPerformance(BaseMailPerformance):
                 'partner_ids': [(4, customer_id)],
             })
 
-        with self.assertQueryCount(admin=35, employee=35):
+        with self.assertQueryCount(admin=34, employee=34):
             composer._action_send_mail()
 
     @users('admin', 'employee')
@@ -358,7 +358,7 @@ class TestMailAPIPerformance(BaseMailPerformance):
         test_record, _test_template = self._create_test_records()
         customer = self.env['res.partner'].browse(self.customer.ids)
         attachments = self.env['ir.attachment'].with_user(self.env.user).create(self.test_attachments_vals)
-        with self.assertQueryCount(admin=3, employee=3):
+        with self.assertQueryCount(admin=4, employee=4):
             composer = self.env['mail.compose.message'].with_context({
                 'default_composition_mode': 'comment',
                 'default_model': test_record._name,
@@ -369,7 +369,7 @@ class TestMailAPIPerformance(BaseMailPerformance):
                 'partner_ids': [(4, customer.id)],
             })
 
-        with self.assertQueryCount(admin=38, employee=38):
+        with self.assertQueryCount(admin=37, employee=37):
             composer._action_send_mail()
 
     @users('admin', 'employee')
@@ -426,7 +426,7 @@ class TestMailAPIPerformance(BaseMailPerformance):
     def test_mail_composer_nodelete(self):
         test_record, _test_template = self._create_test_records()
         customer_id = self.customer.id
-        with self.assertQueryCount(admin=3, employee=3):
+        with self.assertQueryCount(admin=4, employee=4):
             composer = self.env['mail.compose.message'].with_context({
                 'default_composition_mode': 'comment',
                 'default_model': test_record._name,
@@ -437,7 +437,7 @@ class TestMailAPIPerformance(BaseMailPerformance):
                 'partner_ids': [(4, customer_id)],
             })
 
-        with self.assertQueryCount(admin=35, employee=35):
+        with self.assertQueryCount(admin=34, employee=34):
             composer._action_send_mail()
 
     @users('admin', 'employee')