# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1360883806 -3600
# Node ID fec3a1bd649a0e21461564b0a59c445a33079ae7
# Parent  6c21fb6d057f62bb4cd943f9d5ae06eb17ac178a
Added error message output when form data cannot be accessed.

diff -r 6c21fb6d057f -r fec3a1bd649a MoinForms.py
--- a/MoinForms.py	Sat Feb 09 20:15:05 2013 +0100
+++ b/MoinForms.py	Fri Feb 15 00:16:46 2013 +0100
@@ -19,6 +19,12 @@
 form_field_regexp_str = r"<<Form(Field|Message)\((.*?)\)>>"
 form_field_regexp = re.compile(form_field_regexp_str, re.DOTALL)
 
+class MoinFormDataError(Exception):
+
+    "An exception indicating a problem with form data."
+
+    pass
+
 # Common action functionality.
 
 class MoinFormHandlerAction:
@@ -64,7 +70,25 @@
             else:
                 self.attributes, text = self.getFormForFragment(fields)
                 self.access_handler = self.getAccessHandler()
-                fields = self.loadFields(number)
+
+                # Attempt to load the form.
+
+                try:
+                    fields = self.loadFields(number)
+
+                # Absent or inaccessible forms will result in an IndexError.
+
+                except IndexError:
+                    self.request.theme.add_msg(_("The stored data for this form cannot be accessed."), "error")
+                    do_show(self.pagename, self.request)
+                    return
+
+                # Bad data will result in a MoinFormDataError.
+
+                except MoinFormDataError:
+                    self.request.theme.add_msg(_("The stored data for this form is in the wrong format."), "error")
+                    do_show(self.pagename, self.request)
+                    return
 
             self.unfinished(fields, form)
 
@@ -311,18 +335,12 @@
     submission 'number'.
     """
 
-    try:
-        text = store[number]
-        module = parse(text)
-        if checkStoredFormData(module):
-            return eval(text)
-
-    # NOTE: Should indicate any errors in retrieving form data.
-
-    except:
-        pass
-
-    return {}
+    text = store[number]
+    module = parse(text)
+    if checkStoredFormData(module):
+        return eval(text)
+    else:
+        raise MoinFormDataError, text
 
 def checkStoredFormData(node):