BUG: Fix crash in repr of void subclasses

eric-wieser · eric-wieser · commit 0ec2a4f581c3 · 2018-10-21T23:48:03.000-07:00
Fixes numpy#12206, which was a regression introduced by numpy#10602 Frankly I'd consider the results expected by `test_void_subclass_unsized` and `test_void_subclass_sized` undesirable, but they match the behavior in 1.12.x
diff --git a/numpy/core/_dtype.py b/numpy/core/_dtype.py
@@ -138,7 +138,9 @@ def _scalar_str(dtype, short):
         else:
             return "'%sU%d'" % (byteorder, dtype.itemsize / 4)
 
-    elif dtype.type == np.void:
+    # unlike the other types, subclasses of void are preserved - but
+    # historically the repr does not actually reveal the subclass
+    elif issubclass(dtype.type, np.void):
         if _isunsized(dtype):
             return "'V'"
         else:
diff --git a/numpy/core/tests/test_dtype.py b/numpy/core/tests/test_dtype.py
@@ -620,6 +620,25 @@ def test_empty_string_to_object(self):
         # Pull request #4722
         np.array(["", ""]).astype(object)
 
+    def test_void_subclass_unsized(self):
+        dt = np.dtype(np.record)
+        assert_equal(repr(dt), "dtype('V')")
+        assert_equal(str(dt), '|V0')
+        assert_equal(dt.name, 'record')
+
+    def test_void_subclass_sized(self):
+        dt = np.dtype((np.record, 2))
+        assert_equal(repr(dt), "dtype('V2')")
+        assert_equal(str(dt), '|V2')
+        assert_equal(dt.name, 'record16')
+
+    def test_void_subclass_fields(self):
+        dt = np.dtype((np.record, [('a', '<u2')]))
+        assert_equal(repr(dt), "dtype((numpy.record, [('a', '<u2')]))")
+        assert_equal(str(dt), "(numpy.record, [('a', '<u2')])")
+        assert_equal(dt.name, 'record16')
+
+
 class TestDtypeAttributeDeletion(object):
 
     def test_dtype_non_writable_attributes_deletion(self):
