make Task.inputs namespace read-only

esrftaskgraph/esrftaskgraph/task.py

@@ -2,6 +2,7 @@ from esrftaskgraph import hashing
 from esrftaskgraph.variable import VARINFO
 from esrftaskgraph.variable import VariableContainer
 from esrftaskgraph.variable import VariableContainerNamespace
+from esrftaskgraph.variable import ReadOnlyVariableContainerNamespace
 from esrftaskgraph.registration import Registered
 
 
@@ -53,7 +54,7 @@ class Task(Registered, hashing.UniversalHashable, register=False):
             value=ovars, uhash=self._inputs, uhash_nonce=self.class_nonce(), **varkw
         )
 
-        self._user_inputs = VariableContainerNamespace(self._inputs)
+        self._user_inputs = ReadOnlyVariableContainerNamespace(self._inputs)
         self._user_outputs = VariableContainerNamespace(self._outputs)
 
         # The task class has the same hash as its output

esrftaskgraph/esrftaskgraph/variable.py

@@ -326,7 +326,11 @@ class MutableVariableContainer(VariableContainer, MutableMapping):
             del self.value[name]
 
 
-class UnknownVariableError(AttributeError):
+class UnknownVariableError(RuntimeError):
+    pass
+
+
+class ReadOnlyVariableError(RuntimeError):
     pass
 
 
@@ -358,3 +362,11 @@ class VariableContainerNamespace:
             return self._container[name]
         except (KeyError, TypeError):
             raise UnknownVariableError(name)
+
+
+class ReadOnlyVariableContainerNamespace(VariableContainerNamespace):
+    def __setattr__(self, name, value):
+        if name in self._reserved_variable_names():
+            super(VariableContainerNamespace, self).__setattr__(name, value)
+        else:
+            raise ReadOnlyVariableError(name)

esrftaskgraph/tests/test_task.py

@@ -36,6 +36,12 @@ def test_task_missing_input(variable_kwargs):
         SumTask(**variable_kwargs)
 
 
+def test_task_readonly_input(variable_kwargs):
+    task = SumTask(a=10, **variable_kwargs)
+    with pytest.raises(RuntimeError):
+        task.inputs.a = 10
+
+
 def test_task_optional_input(tmpdir, variable_kwargs):
     task = SumTask(a=10, **variable_kwargs)
     assert not task.done
@@ -52,7 +58,7 @@ def test_task_uhash(variable_kwargs):
     assert task.uhash == task.output_variables.uhash
     assert task.uhash != task.input_variables.uhash
 
-    task.inputs.a += 1
+    task.input_variables["a"].value += 1
     assert task.uhash != uhash
     assert task.uhash == task.output_variables.uhash
     assert task.uhash != task.input_variables.uhash
@@ -60,7 +66,7 @@ def test_task_uhash(variable_kwargs):
     task.run()
     assert task.done
 
-    task.inputs.a += 1
+    task.input_variables["a"].value += 1
     assert task.uhash != uhash
     assert task.uhash == task.output_variables.uhash
     assert task.uhash != task.input_variables.uhash