BUG: recfunctions: Don't return None in place of empty sequences

Replacing empty tuples with `None` is a bad idea, and just results in an API that is hard to consume - especially since the behavior was never documented.

This affects `get_names`, `get_names_flat`, and `get_fieldstructure`.

1 files changed, 21 insertions, 0 deletions

diff --git a/numpy/lib/tests/test_recfunctions.py b/numpy/lib/tests/test_recfunctions.py
index 11f8a5afa..3b972f4b1 100644
--- a/numpy/lib/tests/test_recfunctions.py
+++ b/numpy/lib/tests/test_recfunctions.py
@@ -113,6 +113,14 @@ class TestRecFunctions(object):
         test = get_names(ndtype)
         assert_equal(test, ('a', ('b', ('ba', 'bb'))))
 
+        ndtype = np.dtype([('a', int), ('b', [])])
+        test = get_names(ndtype)
+        assert_equal(test, ('a', ('b', ())))
+
+        ndtype = np.dtype([])
+        test = get_names(ndtype)
+        assert_equal(test, ())
+
     def test_get_names_flat(self):
         # Test get_names_flat
         ndtype = np.dtype([('A', '|S3'), ('B', float)])
@@ -123,6 +131,14 @@ class TestRecFunctions(object):
         test = get_names_flat(ndtype)
         assert_equal(test, ('a', 'b', 'ba', 'bb'))
 
+        ndtype = np.dtype([('a', int), ('b', [])])
+        test = get_names_flat(ndtype)
+        assert_equal(test, ('a', 'b'))
+
+        ndtype = np.dtype([])
+        test = get_names_flat(ndtype)
+        assert_equal(test, ())
+
     def test_get_fieldstructure(self):
         # Test get_fieldstructure
 
@@ -145,6 +161,11 @@ class TestRecFunctions(object):
                    'BBA': ['B', 'BB'], 'BBB': ['B', 'BB']}
         assert_equal(test, control)
 
+        # 0 fields
+        ndtype = np.dtype([])
+        test = get_fieldstructure(ndtype)
+        assert_equal(test, {})
+
     def test_find_duplicates(self):
         # Test find_duplicates
         a = ma.array([(2, (2., 'B')), (1, (2., 'B')), (2, (2., 'B')),