[FIX] survey: Generate unique access_token

Populate a unique token for each existing survey, as default method populates the same
for all.

Co-authored by: Graeme Gellatly <gdgellatly@gmail.com>

addons/survey/migrations/13.0.3.0/openupgrade_analysis_work.txt

@@ -81,7 +81,6 @@ survey       / survey.survey            / certification_mail_template_id (many2o
 # DONE: pre-migration (renamed)
 
 survey       / survey.survey            / access_mode (selection)       : NEW required, selection_keys: ['public', 'token'], req_default: function, hasdefault
-survey       / survey.survey            / access_token (char)           : NEW hasdefault
 survey       / survey.survey            / attempts_limit (integer)      : NEW hasdefault
 survey       / survey.survey            / category (selection)          : NEW required, selection_keys: ['default'], req_default: function, hasdefault
 survey       / survey.survey            / certificate (boolean)         : NEW
@@ -96,6 +95,9 @@ survey       / survey.survey            / scoring_type (selection)      : NEW re
 survey       / survey.survey            / time_limit (float)            : NEW
 # NOTHING TO DO: new feature with proper defaults
 
+survey       / survey.survey            / access_token (char)           : NEW hasdefault
+# DONE: pre-migration: populate a unique UUID before the constraint is added, as the default brings the same for all
+
 survey       / survey.user_input        / input_type (selection)        : NEW required, selection_keys: ['link', 'manually'], req_default: function, hasdefault
 survey       / survey.user_input        / type (selection)              : DEL required, selection_keys: ['link', 'manually'], req_default: function
 # DONE: pre-migration (renamed)

addons/survey/migrations/13.0.3.0/pre-migration.py

@@ -2,6 +2,7 @@
 # Copyright 2020 ForgeFlow <https://www.forgeflow.com>
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 from openupgradelib import openupgrade
+import uuid
 
 _model_renames = [
     ('survey.mail.compose.message', 'survey.invite'),
@@ -82,6 +83,20 @@ def fill_survey_user_input_line_question_sequence(env):
     )
 
 
+def unique_survey_tokens(env):
+    """Populate a unique token for each existing survey, as default method
+    populates the same for all. Done this on pre-migration for avoiding the
+    unique constraint.
+    """
+    openupgrade.add_fields(env, [("access_token", "survey.survey", "survey_survey", "char", False, "survey")])
+    env.cr.execute("SELECT id FROM survey_survey")
+    for row in env.cr.fetchall():
+        env.cr.execute(
+            "UPDATE survey_survey SET access_token = %s WHERE id = %s",
+            (str(uuid.uuid4()), row[0])
+        )
+
+
 @openupgrade.migrate()
 def migrate(env, version):
     openupgrade.rename_models(env.cr, _model_renames)
@@ -91,6 +106,7 @@ def migrate(env, version):
     openupgrade.rename_xmlids(env.cr, _xmlid_renames)
     add_helper_survey_question_page_rel(env)
     fill_survey_user_input_line_question_sequence(env)
+    unique_survey_tokens(env)
     openupgrade.set_xml_ids_noupdate_value(
         env,
         "survey",