BUG: for 1.14 back-compat, accept list-of-lists in fromrecords

Fixes #10870

2 files changed, 40 insertions, 24 deletions

diff --git a/numpy/core/records.py b/numpy/core/records.py
index 612d39322..b3f285584 100644
--- a/numpy/core/records.py
+++ b/numpy/core/records.py
@@ -676,32 +676,40 @@ def fromrecords(recList, dtype=None, shape=None, formats=None, names=None,
     else:
         descr = format_parser(formats, names, titles, aligned, byteorder)._descr
 
-    try:
-        retval = sb.array(recList, dtype=descr)
-    except (TypeError, ValueError):
-        if (shape is None or shape == 0):
-            shape = len(recList)
-        if isinstance(shape, (int, long)):
-            shape = (shape,)
-        if len(shape) > 1:
-            raise ValueError("Can only deal with 1-d array.")
-        _array = recarray(shape, descr)
-        for k in range(_array.size):
-            _array[k] = tuple(recList[k])
-        # list of lists instead of list of tuples ?
-        # 2018-02-07, 1.14.1
-        warnings.warn(
-            "fromrecords expected a list of tuples, may have received a list "
-            "of lists instead. In the future that will raise an error",
-            FutureWarning, stacklevel=2)
-        return _array
-    else:
-        if shape is not None and retval.shape != shape:
-            retval.shape = shape
+    # deprecated back-compat block for numpy 1.14, to be removed in a later
+    # release. This converts list-of-list input to list-of-tuples in some
+    # cases, as done in numpy <= 1.13. In the future we will require tuples.
+    if (isinstance(recList, list) and len(recList) > 0
+            and isinstance(recList[0], list) and len(recList[0]) > 0
+            and not isinstance(recList[0][0], (list, tuple))):
+
+        try: 
+            memoryview(recList[0][0]) 
+        except:
+            if (shape is None or shape == 0):
+                shape = len(recList)
+            if isinstance(shape, (int, long)):
+                shape = (shape,)
+            if len(shape) > 1:
+                raise ValueError("Can only deal with 1-d array.")
+            _array = recarray(shape, descr)
+            for k in range(_array.size):
+                _array[k] = tuple(recList[k])
+            # list of lists instead of list of tuples ?
+            # 2018-02-07, 1.14.1
+            warnings.warn(
+                "fromrecords expected a list of tuples, may have received a "
+                "list of lists instead. In the future that will raise an error",
+                FutureWarning, stacklevel=2)
+            return _array
+        else:
+            pass
 
-    res = retval.view(recarray)
+    retval = sb.array(recList, dtype=descr)
+    if shape is not None and retval.shape != shape:
+        retval.shape = shape
 
-    return res
+    return retval.view(recarray)
 
 
 def fromstring(datastring, dtype=None, shape=None, offset=0, formats=None,
diff --git a/numpy/core/tests/test_records.py b/numpy/core/tests/test_records.py
index 691e56d80..3c1744519 100644
--- a/numpy/core/tests/test_records.py
+++ b/numpy/core/tests/test_records.py
@@ -54,6 +54,14 @@ class TestFromrecords(object):
 
         assert_equal(r1, r2)
 
+    def test_fromrecords_list_of_lists(self):
+        # gh-10870 : For numpy 1.14 we keep the deprecated behavior
+        # that 1d list-of-lists input is accepted by fromrecords
+        expected = np.rec.array([(1,  1.5), (2,  2.5)], dtype='i8,f8')
+        with assert_warns(FutureWarning):
+            r = np.rec.fromrecords([[1, 1.5], [2, 2.5]], dtype='i8,f8')
+        assert_equal(r, expected)
+
     def test_method_array(self):
         r = np.rec.array(b'abcdefg' * 100, formats='i2,a3,i4', shape=3, byteorder='big')
         assert_equal(r[1].item(), (25444, b'efg', 1633837924))