[HOTFIX] Fix hash key calculation when using non-hashable function ar…

…guments.

PostProcessing/python/Palisade/_input.py

@@ -43,19 +43,25 @@ class HashableMap(Mapping):
     """
 
     def __init__(self, *args, **kwargs):
+
         self._d = dict(*args, **kwargs)
 
         # validate values
         for key, value in six.iteritems(self._d):
-            # make lists hashable by casting to tuple
-            if isinstance(value, list):
-                value = tuple(value)
-
             # check hashability
             try:
                 hash(value)
             except TypeError:
                 # attempt to wrap non-hashable types
+                if isinstance(value, list) or isinstance(value, tuple):
+                    print("Wrap list/tuple: ", value)
+                    value = tuple(enumerate(value))
+                elif isinstance(value, dict):
+                    print("Wrap dict: ", value)
+                    value = tuple(six.iteritems(value))
+                else:
+                    raise
+
                 self._d[key] = HashableMap(value)
 
         self._hash = None  # computed on request

PostProcessing/test/Palisade/test_input.py

@@ -347,6 +347,22 @@ def triple_memoized(tobject):
         # remove function to avoid side effects
         InputROOT.functions.pop('triple_memoized', None)
 
+    def test_get_expr_user_defined_function_memoized_list_arguments(self):
+
+        # add a custom function: scale hist by a factor 3
+        @InputROOT.add_function(memoize=True)
+        def how_many(tobjects):
+            return len(tobjects)
+
+        # evaluate expr and compute reference reult
+        _result_expr = self._ic.get_expr('how_many(["test:h1", "test:h1", "test:h1"])')
+
+        # bin-by-bin comparison
+        self.assertEqual(_result_expr, 3)
+
+        # remove function to avoid side effects
+        InputROOT.functions.pop('how_many', None)
+
     def test_get_expr_local_variables(self):
 
         with self.subTest(test_label="call_local_variable"):