[erp5] Form/FormBox does not hold context reference but only method_getter name

Fixed bug reported by nexedi/erp5@a5a2f1cd (comment 38674)

/reviewed-on nexedi/erp5!363

product/ERP5Form/FormBox.py

@@ -42,7 +42,6 @@ from Products.PythonScripts.standard import url_quote_plus
 from Products.Formulator.Errors import FormValidationError, ValidationError
 
 import string
-import copy
 
 class FormBoxWidget(Widget.Widget):
   """
@@ -121,18 +120,18 @@ class FormBoxWidget(Widget.Widget):
     return ''
 
 class FormBoxEditor:
-  """
-  A class holding all values required to update the object
-  """
-  def __init__(self, field_id, result, context=None):
-    """Initialize with all necessary information for editing.
+  """An editor returned from FormBox validation able to `edit` document."""
 
-    Keep a reference to the correct context and don't expect the caller to provide it
-    during the edit phase because they don't have access to the widget anymore.
+  def __init__(self, result, context_method_id=None):
+    """Initialize with all necessary information for editing a document.
+
+    :result: tuple of attributes, editors intended as parameters for edit function
+    :context_method_id: editor needs to operate on the correct context (Document)
+                        but it cannot hold reference because then weird failures
+                        appear; thus we keep name of the context-obtaining method
     """
-    self.field_id = field_id
     self.attr_dict, self.editor_list = result
-    self.context = context
+    self.context_method_id = context_method_id
 
   def view(self):
     return self.__dict__
@@ -141,10 +140,8 @@ class FormBoxEditor:
     pass
 
   def edit(self, context):
-    """Edit inside correct context."""
-    if self.context is not None:
-        context = self.context
-
+    if self.context_method_id:
+      context = getattr(context, self.context_method_id)
     context.edit(**self.attr_dict)
     for encapsulated_editor in self.editor_list:
       encapsulated_editor.edit(context)
@@ -155,7 +152,7 @@ class FormBoxEditor:
     XXX This API is probably not stable and may change, as some editors are used to
     edit multiple objects.
     """
-    result_dict = copy.copy(self.attr_dict)
+    result_dict = self.attr_dict.copy()  # avoid modifying own attribute
     for encapsulated_editor in self.editor_list:
       if hasattr(encapsulated_editor, 'as_dict'):
         result_dict.update(
@@ -192,7 +189,7 @@ class FormBoxValidator(Validator.Validator):
     # XXX Hardcode script name
     result, result_type = here.Base_edit(formbox_target_id, silent_mode=1, key_prefix=key)
     if result_type == 'edit':
-      return FormBoxEditor(field.id, result, context=here)
+      return FormBoxEditor(result, context_method_id)
     elif result_type == 'form':
       formbox_field_errors = REQUEST.get('field_errors', [])
       current_field_errors.extend(formbox_field_errors)