[FIX] base: keep translations for null src while upgrade

The method ``update_translatable_fields`` is inspired in the core
``_get_translation_upgrade_queries`` method, which had a bug that has
been recently addressed in odoo/odoo#168038

Also, we're avoiding removing any original ir_translation record so we
can address any further issue easly without needing to redump the table
from the former DB.

For html/xml tranlatable fields we'll use
``openupgrade_160.migrate_translations_to_jsonb`` which calls to the
proper core method in ``end-migration``.

Ideally we'd like to do everything with that method, but it relies on
having the models already in the registry, and that doesn't happen when
we're in `base`.

Rationale from Odoo's fix:

Before Odoo 16.0, it is possible to have database column whose value is ``NULL``
but still has translations in the ir_translation table. And these translations
can be displayed correctly in the UI.

How to reproduce before Odoo 16.0:
1. Open the form view of a record with non-required translated field.
   E.g. product.template.sale_description
2. Create a new record without touching the translated field for test
3. Directly click the translation button and fill all translations
4. click save
The column for the record's translated field has ``NULL`` value, and the
ir_translation table has new translation records with ``NULL`` in the src column

During upgrade, when the column value is converted to jsonb for the translated
field by the ORM, it will still be ``NULL``. And in the upgrade script when
update the value with all translations, the result will still be ``NULL``. E.g.
``NULL || '{"fr_FR": "french"}'::jsonb``
``NULL || '{"en_US": "english", "fr_FR": "french"}'::jsonb``

In this commit, for the above corner case, we assume the src was empty string
instead of NULL. In the above example, the result would be
``'{"en_US": ""}'::jsonb || '{"fr_FR": "french"}'::jsonb``
``'{"en_US": ""}'::jsonb || '{"en_US": "english", "fr_FR": "french"}'::jsonb``

TT49615

openupgrade_scripts/scripts/base/16.0.1.3/end-migration.py

@@ -0,0 +1,44 @@
+# Copyright 2024 Tecnativa - David Vidal
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+
+from openupgradelib import openupgrade, openupgrade_160
+
+from odoo.tools import column_exists
+
+
+def update_callable_translatable_fields(env):
+    """Use Odoo's core method to get complete translations of translated fields with
+    a callable method for translations (html_translate, xml_translate)"""
+    exclusions = [
+        # ir.actions.* inherits the name and help columns from ir.actions.actions
+        ("ir.actions.act_window", "name"),
+        ("ir.actions.act_window", "help"),
+        ("ir.actions.act_url", "name"),
+        ("ir.actions.act_url", "help"),
+        ("ir.actions.server", "name"),
+        ("ir.actions.server", "help"),
+        ("ir.actions.client", "name"),
+        ("ir.actions.client", "help"),
+        ("ir.actions.report", "name"),
+        ("ir.actions.report", "help"),
+    ]
+    fields = env["ir.model.fields"].search_read(
+        [("translate", "=", True)], ["model", "name"]
+    )
+    fields_spec = [
+        (f["model"], f["name"])
+        for f in fields
+        if (
+            (f["model"], f["name"]) not in exclusions
+            and f["model"] in env
+            and column_exists(env.cr, env[f["model"]]._table, f["name"])
+            and f["name"] in env[f["model"]]._fields
+            and callable(env[f["model"]]._fields[f["name"]].translate)
+        )
+    ]
+    openupgrade_160.migrate_translations_to_jsonb(env, fields_spec)
+
+
+@openupgrade.migrate()
+def migrate(env, version):
+    update_callable_translatable_fields(env)

openupgrade_scripts/scripts/base/16.0.1.3/pre-migration.py

@@ -86,6 +86,7 @@ def update_translatable_fields(cr):
             continue
         # borrowed from odoo/tools/translate.py#_get_translation_upgrade_queries
         translation_name = "%s,%s" % (model, field)
+        emtpy_src = """'{"en_US": ""}'::jsonb"""
         openupgrade.logged_query(
             cr,
             f"""
@@ -98,8 +99,10 @@ def update_translatable_fields(cr):
                 GROUP BY it.res_id
             )
             UPDATE {table} m
-            SET "{field}" = CASE WHEN t.noupdate IS FALSE THEN t.value || m."{field}"
-                                 ELSE m."{field}" || t.value END
+            SET "{field}" = CASE
+                WHEN m."{field}" IS NULL THEN {emtpy_src} || t.value
+                WHEN t.noupdate IS FALSE THEN t.value || m."{field}"
+                ELSE m."{field}" || t.value END
             FROM t
             WHERE t.res_id = m.id
             """,
@@ -108,11 +111,6 @@ def update_translatable_fields(cr):
                 "name": translation_name,
             },
         )
-        openupgrade.logged_query(
-            cr,
-            "DELETE FROM ir_translation WHERE type = 'model' AND name = %s",
-            [translation_name],
-        )
 
 
 @openupgrade.migrate(use_env=False)