set REQUEST['original_context'] in FormBox if context_method_id is used.

so that we can reach the original context where FormBox is used.
also clean up modified REQUEST after rendering the target form.

product/ERP5Form/FormBox.py

@@ -112,13 +112,16 @@ class FormBoxWidget(Widget.Widget):
       here = REQUEST['here']
       context_method_id = field.get_value('context_method_id')
       if context_method_id:
-        original_here = here
+        REQUEST['original_context'] = original_here = here
         REQUEST['here'] = here = getattr(here, context_method_id)()
       # If 'cell' is not defined, we define 'cell' just same as 'here', so
       # that we can use the same formbox for both ListBox and non-ListBox
       # using 'cell' parameter.
       if not REQUEST.has_key('cell'):
+        set_cell = True
         REQUEST.set('cell', here)
+      else:
+        set_sell = False
       try:
         form = getattr(here, target_id)
       except AttributeError:
@@ -130,6 +133,9 @@ class FormBoxWidget(Widget.Widget):
       finally:
         if context_method_id:
           REQUEST['here'] = original_here
+          del REQUEST.other['original_context']
+        if set_cell:
+          del REQUEST.other['cell']
     return result
 
 class FormBoxEditor:

[Julien Muchembled]

@kazuhiko Everything done here with cell is wrong from the beginning because as soon as it's set, it's used to get values. Reverting the setting of cell in the finally: clause does not solve anything: even if you fix things for the caller, it may still bug for the callees.

I wish we could have a tree of FormBoxes, of any depth, with a ListBox in some branches. In a project, we have FormBox(FormBox, ListBox):

• I don't want the inner FormBox to be rendered with cell=here of the outter one.
• The ListBox removes cell once it's rendered, causing the outter FormBox to crash. Well, here it would be an issue of ListBox, but ListBox inside ListBox is weird.

Similarly but easier to fix: REQUEST['original_context'] is overridden, which also prevents FormBox inside FormBox if context_method_id is used in both fields.

And the only way to modify/restore REQUEST safely is to manipulate REQUEST.other directly for everything.

/cc @romain @jerome @vpelletier @seb