Merge pull request #693 from ArvidJB/issue-475

filmor · web-flow · commit 3eb7e58f9488 · 2018-06-26T10:55:02.000+02:00
Catching exceptions from iterator MoveNext(), additional testing (issue #475, original pull request #523)
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -16,6 +16,7 @@ This document follows the conventions laid out in [Keep a CHANGELOG][].
 -   Added `clr.GetClrType` (#432, #433)
 -   Allowed passing `None` for nullable args (#460)
 -   Added keyword arguments based on C# syntax for calling CPython methods (#461)
+-   Catches exceptions thrown in C# iterators (yield returns) and rethrows them in python (#475)
 -   Implemented GetDynamicMemberNames() for PyObject to allow dynamic object members to be visible in the debugger (#443)
 
 ### Changed
@@ -29,7 +30,7 @@ This document follows the conventions laid out in [Keep a CHANGELOG][].
 -   Fixed conversion of 'float' and 'double' values (#486)
 -   Fixed 'clrmethod' for python 2 (#492)
 -   Fixed double calling of constructor when deriving from .NET class (#495)
--   Fixed `clr.GetClrType` when iterating over `System` members (#607) 
+-   Fixed `clr.GetClrType` when iterating over `System` members (#607)
 -   Fixed `LockRecursionException` when loading assemblies (#627)
 -   Fixed errors breaking .NET Remoting on method invoke (#276)
 -   Fixed PyObject.GetHashCode (#676)
diff --git a/src/runtime/iterator.cs b/src/runtime/iterator.cs
@@ -23,9 +23,21 @@ public Iterator(IEnumerator e)
         public static IntPtr tp_iternext(IntPtr ob)
         {
             var self = GetManagedObject(ob) as Iterator;
-            if (!self.iter.MoveNext())
+            try
             {
-                Exceptions.SetError(Exceptions.StopIteration, Runtime.PyNone);
+                if (!self.iter.MoveNext())
+                {
+                    Exceptions.SetError(Exceptions.StopIteration, Runtime.PyNone);
+                    return IntPtr.Zero;
+                }
+            }
+            catch (Exception e)
+            {
+                if (e.InnerException != null)
+                {
+                    e = e.InnerException;
+                }
+                Exceptions.SetError(e);
                 return IntPtr.Zero;
             }
             object item = self.iter.Current;
diff --git a/src/testing/exceptiontest.cs b/src/testing/exceptiontest.cs
@@ -1,4 +1,6 @@
 using System;
+using System.Collections;
+using System.Collections.Generic;
 
 namespace Python.Test
 {
@@ -54,6 +56,13 @@ public static bool ThrowException()
             throw new OverflowException("error");
         }
 
+        public static IEnumerable<int> ThrowExceptionInIterator(Exception e)
+        {
+            yield return 1;
+            yield return 2;
+            throw e;
+        }
+
         public static void ThrowChainedExceptions()
         {
             try
diff --git a/src/tests/test_exceptions.py b/src/tests/test_exceptions.py
@@ -345,3 +345,44 @@ def test_chained_exceptions():
         assert exc.Message == msg
         assert exc.__cause__ == exc.InnerException
         exc = exc.__cause__
+
+def test_iteration_exception():
+    from Python.Test import ExceptionTest
+    from System import OverflowException
+
+    exception = OverflowException("error")
+
+    val = ExceptionTest.ThrowExceptionInIterator(exception).__iter__()
+    assert next(val) == 1
+    assert next(val) == 2
+    with pytest.raises(OverflowException) as cm:
+        next(val)
+
+    exc = cm.value
+
+    assert exc == exception
+
+    # after exception is thrown iterator is no longer valid
+    with pytest.raises(StopIteration):
+        next(val)
+
+
+def test_iteration_innerexception():
+    from Python.Test import ExceptionTest
+    from System import OverflowException
+
+    exception = System.Exception("message", OverflowException("error"))
+
+    val = ExceptionTest.ThrowExceptionInIterator(exception).__iter__()
+    assert next(val) == 1
+    assert next(val) == 2
+    with pytest.raises(OverflowException) as cm:
+        next(val)
+
+    exc = cm.value
+
+    assert exc == exception.InnerException
+
+    # after exception is thrown iterator is no longer valid
+    with pytest.raises(StopIteration):
+        next(val)

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,6 @@`
`1`	`1`	`using System;`
	`2`	`+using System.Collections;`
	`3`	`+using System.Collections.Generic;`
`2`	`4`
`3`	`5`	`namespace Python.Test`
`4`	`6`	`{`
`@@ -54,6 +56,13 @@ public static bool ThrowException()`
`54`	`56`	`throw new OverflowException("error");`
`55`	`57`	`}`
`56`	`58`
	`59`	`+ public static IEnumerable<int> ThrowExceptionInIterator(Exception e)`
	`60`	`+ {`
	`61`	`+ yield return 1;`
	`62`	`+ yield return 2;`
	`63`	`+ throw e;`
	`64`	`+ }`
	`65`	`+`
`57`	`66`	`public static void ThrowChainedExceptions()`
`58`	`67`	`{`
`59`	`68`	`try`