fix missing import in change message

Transported values in a change must be converted first.
As this is only relevant for the exotic "scaled" and "blob"
datatypes, this was not detected yet.

- add tests
- suppress warning PytestUnhandledThreadExceptionWarning in tests
+ change import_value methods to raise no other exceptions than
  WrongTypeError and RangeError
+ simplify Command.do: as import_value already raises the
  appropriate error, no more try/except is needed

Change-Id: I299e511468dc0fcecff4c20cf8a917da38b70786
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/32743
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Alexander Zaft <a.zaft@fz-juelich.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

frappy/datatypes.py

@@ -105,7 +105,7 @@ class DataType(HasProperties):
         note: for importing from gui/configfile/commandline use :meth:`from_string`
         instead.
         """
-        return value
+        return self(value)
 
     def format_value(self, value, unit=None):
         """format a value of this type into a str string
@@ -259,10 +259,6 @@ class FloatRange(HasUnit, DataType):
         """returns a python object fit for serialisation"""
         return float(value)
 
-    def import_value(self, value):
-        """returns a python object from serialisation"""
-        return float(value)
-
     def from_string(self, text):
         value = float(text)
         return self(value)
@@ -341,10 +337,6 @@ class IntRange(DataType):
         """returns a python object fit for serialisation"""
         return int(value)
 
-    def import_value(self, value):
-        """returns a python object from serialisation"""
-        return int(value)
-
     def from_string(self, text):
         value = int(text)
         return self(value)
@@ -461,7 +453,10 @@ class ScaledInteger(HasUnit, DataType):
 
     def import_value(self, value):
         """returns a python object from serialisation"""
-        return self.scale * int(value)
+        try:
+            return self.scale * int(value)
+        except Exception:
+            raise WrongTypeError(f'can not import {shortrepr(value)} to scaled') from None
 
     def from_string(self, text):
         value = float(text)
@@ -513,10 +508,6 @@ class EnumType(DataType):
         """returns a python object fit for serialisation"""
         return int(self(value))
 
-    def import_value(self, value):
-        """returns a python object from serialisation"""
-        return self(value)
-
     def __call__(self, value):
         """accepts integers and strings, converts to EnumMember (may be used like an int)"""
         try:
@@ -588,7 +579,10 @@ class BLOBType(DataType):
 
     def import_value(self, value):
         """returns a python object from serialisation"""
-        return b64decode(value)
+        try:
+            return b64decode(value)
+        except Exception:
+            raise WrongTypeError(f'can not b64decode {shortrepr(value)}') from None
 
     def from_string(self, text):
         value = text
@@ -659,10 +653,6 @@ class StringType(DataType):
         """returns a python object fit for serialisation"""
         return f'{value}'
 
-    def import_value(self, value):
-        """returns a python object from serialisation"""
-        return str(value)
-
     def from_string(self, text):
         value = str(text)
         return self(value)
@@ -723,10 +713,6 @@ class BoolType(DataType):
         """returns a python object fit for serialisation"""
         return self(value)
 
-    def import_value(self, value):
-        """returns a python object from serialisation"""
-        return self(value)
-
     def from_string(self, text):
         value = text
         return self(value)

frappy/params.py

@@ -499,7 +499,7 @@ class Command(Accessible):
         """perform function call
 
         :param module_obj: the module on which the command is to be executed
-        :param argument: the argument from the do command
+        :param argument: the argument from the do command (transported value!)
         :returns: the return value converted to the result type
 
         - when the argument type is TupleOf, the function is called with multiple arguments
@@ -514,13 +514,9 @@ class Command(Accessible):
                     f'{module_obj.__class__.__name__}.{self.name} needs an'
                     f' argument of type {self.argument}!'
                 )
-            try:
-                argument = self.argument.import_value(argument)
-            except TypeError:
-                pass  # validate will raise appropriate message
-            except ValueError:
-                pass  # validate will raise appropriate message
-
+            # convert transported value to internal value
+            argument = self.argument.import_value(argument)
+            # verify range
             self.argument.validate(argument)
             if isinstance(self.argument, TupleOf):
                 res = func(*argument)

frappy/protocol/dispatcher.py

@@ -162,7 +162,9 @@ class Dispatcher:
         if pobj.readonly:
             raise ReadOnlyError(f"Parameter {modulename}:{pname} can not be changed remotely")
 
-        # validate!
+        # convert transported value to internal value
+        value = pobj.datatype.import_value(value)
+        # verify range
         value = pobj.datatype.validate(value, previous=pobj.value)
         # note: exceptions are handled in handle_request, not here!
         getattr(moduleobj, 'write_' + pname)(value)