BUG: Work around bugs in pep3118 ctypes by falling back on np.dtype(type(ctype_obj))

Fixes gh-10528
Fixes gh-10978
Fixes gh-11150

A warning is thrown when ctypes misbehaves, in order to not hide issues that need fixing upstream

1 files changed, 13 insertions, 0 deletions

diff --git a/numpy/core/_internal.py b/numpy/core/_internal.py
index 8c6596d13..9990bacf0 100644
--- a/numpy/core/_internal.py
+++ b/numpy/core/_internal.py
@@ -756,3 +756,16 @@ def _ufunc_doc_signature_formatter(ufunc):
         out_args=out_args,
         kwargs=kwargs
     )
+
+
+def _is_from_ctypes(obj):
+    # determine if an object comes from ctypes, in order to work around
+    # a bug in the buffer protocol for those objects, bpo-10746
+    try:
+        # ctypes class are new-style, so have an __mro__. This probably fails
+        # for ctypes classes with multiple inheritance.
+        ctype_base = type(obj).__mro__[-2]
+        # right now, they're part of the _ctypes module
+        return 'ctypes' in ctype_base.__module__
+    except Exception:
+        return False