Restore initial state when the execution of a wizard fails

Since 1aad63cbbba7 there is a check that the button from a wizard are triggered
from the same state as they were created.
But when an exception is raised during the execution, the wizard must be put
back to the initial state such that buttons can still be triggered again.

Closes #14895
(grafted from 0eddec418366403871755be8ba3b750a9c0fcdf4)

--HG--
branch : 8.0

sao/src/wizard.js

@@ -43,20 +43,22 @@
                 'params': [this.session.context]
             }, this.session).then(result => {
                 this.session_id = result[0];
-                this.start_state = this.state = result[1];
+                this.start_state = result[1];
                 this.end_state = result[2];
-                return this.process();
+                return this.process(this.start_state);
             }, () => {
                 this.destroy();
             });
             return this.__prm.promise();
         },
-        process: function() {
+        process: function(state) {
             if (this.__processing || this.__waiting_response) {
                 return jQuery.when();
             }
             this.__processing = true;
             var process = function() {
+                let current_state = this.state;
+                this.state = state;
                 if (this.state == this.end_state) {
                     return this.end();
                 }
@@ -121,6 +123,7 @@
                         this.state = this.end_state;
                         this.end();
                     }
+                    this.state = current_state;
                     this.__processing = false;
                 });
             };
@@ -158,8 +161,7 @@
                 return;
             }
             this.info_bar.clear();
-            this.state = definition.state;
-            this.process();
+            this.process(definition.state);
         },
         _get_button: function(definition) {
             var style = 'btn-default';
@@ -401,9 +403,6 @@
         hide: function() {
             this.dialog.modal('hide');
         },
-        state_changed: function() {
-            this.process();
-        }
     });
 
 }());

tryton/tryton/gui/window/wizard.py

@@ -71,11 +71,10 @@ class Wizard(InfoBar):
                 self.destroy()
                 return
             self.session_id, self.start_state, self.end_state = result
-            self.state = self.start_state
-            self.process()
+            self.process(self.start_state)
         RPCExecute('wizard', action, 'create', callback=callback)
 
-    def process(self):
+    def process(self, state):
         from tryton.action import Action
         if self.__processing or self.__waiting_response:
             return
@@ -88,6 +87,7 @@ class Wizard(InfoBar):
                 }
         else:
             data = {}
+        current_state, self.state = self.state, state
 
         def callback(result):
             try:
@@ -98,6 +98,7 @@ class Wizard(InfoBar):
                         or not self.screen):
                     self.state = self.end_state
                     self.end()
+                self.state = current_state
                 self.__processing = False
                 return
 
@@ -179,8 +180,7 @@ class Wizard(InfoBar):
                 self.screen.invalid_message(), Gtk.MessageType.ERROR)
             return
         self.info_bar_clear()
-        self.state = state
-        self.process()
+        self.process(state)
 
     def _get_button(self, definition):
         button = Button(definition)