too many values and too few values errors implemented for list comprehensions tuple unpacking.

jedi/evaluate/analysis.py

@@ -22,6 +22,8 @@ CODES = {
     'type-error-not-iterable': (11, TypeError, None),
     'type-error-isinstance': (12, TypeError, None),
     'type-error-not-subscriptable': (13, TypeError, None),
+    'value-error-too-many-values': (13, ValueError, None),
+    'value-error-too-few-values': (13, ValueError, None),
 }
 
 

jedi/evaluate/iterable.py

@@ -392,16 +392,20 @@ def unpack_tuple_to_dict(evaluator, types, exprlist):
                            'testlist_star_expr'):
         dct = {}
         parts = iter(exprlist.children[::2])
-        for iter_types in py__iter__(evaluator, types, exprlist):
+        n = 1
+        for iter_types in enumerate(py__iter__(evaluator, types, exprlist)):
+            n += 1
             try:
                 part = next(parts)
             except StopIteration:
-                raise NotImplementedError
+                analysis.add(evaluator, 'value-error-too-many-values', part,
+                             message="ValueError: too many values to unpack (expected %s)" % n)
             else:
                 dct.update(unpack_tuple_to_dict(evaluator, iter_types, part))
         has_parts = next(parts, None)
         if has_parts is not None:
-            raise NotImplementedError
+            analysis.add(evaluator, 'value-error-too-few-values', has_parts,
+                         message="ValueError: need more than %s values to unpack" % n)
         return dct
     elif exprlist.type == 'power':
         # Something like ``arr[x], var = ...``.

test/static_analysis/comprehensions.py

@@ -28,3 +28,14 @@ tuple(a + 3 for a in [''])
 
 #! 19 name-error
 (1 for a in [1] if NOT_DEFINED)
+
+# ----------
+# unbalanced sides.
+# ----------
+
+# ok
+(1 for a, b in [(1, 2)])
+#! 13 value-error-too-few-values
+(1 for a, b, c in [(1, 2)])
+#! 10 value-error-too-many-values
+(1 for a, b in [(1, 2, 3)])