Fix error messages for index overflows

coolreader18 · coolreader18 · commit 2fc90e17ac38 · 2020-06-06T17:14:32.000-05:00
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
@@ -54,8 +54,6 @@ def test_copy(self):
             self.assertEqual(a, b)
             self.assertEqual(type(a), type(b))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_empty_sequence(self):
         b = self.type2test()
         self.assertEqual(len(b), 0)
diff --git a/tests/snippets/index_overflow.py b/tests/snippets/index_overflow.py
@@ -4,12 +4,8 @@
 def expect_cannot_fit_index_error(s, index):
     try:
         s[index]
-    except IndexError:
-        pass
-    # TODO: Replace current except block with commented
-    # after solving https://github.com/RustPython/RustPython/issues/322
-    # except IndexError as error:
-    #     assert str(error) == "cannot fit 'int' into an index-sized integer"
+    except IndexError as error:
+        assert str(error) == "cannot fit 'int' into an index-sized integer"
     else:
         assert False
 
diff --git a/vm/src/obj/objsequence.rs b/vm/src/obj/objsequence.rs
@@ -136,10 +136,12 @@ pub enum SequenceIndex {
 impl TryFromObject for SequenceIndex {
     fn try_from_object(vm: &VirtualMachine, obj: PyObjectRef) -> PyResult<Self> {
         match_class!(match obj {
-            i @ PyInt => Ok(SequenceIndex::Int(isize::try_from_object(
-                vm,
-                i.into_object()
-            )?)),
+            i @ PyInt => i
+                .as_bigint()
+                .to_isize()
+                .map(SequenceIndex::Int)
+                .ok_or_else(|| vm
+                    .new_index_error("cannot fit 'int' into an index-sized integer".to_owned())),
             s @ PySlice => Ok(SequenceIndex::Slice(s)),
             obj => Err(vm.new_type_error(format!(
                 "sequence indices be integers or slices, not {}",
