Check if you forgot to specify 'variants: function' on _out (#8402)
The Python binding generation code doesn't understand
method '_out' bindings correctly, and will compute the
indices wrong if you have an '_out' function that's also
method. This is a quick check to prevent you from making
this mistake.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
diff --git a/aten/src/ATen/native_parse.py b/aten/src/ATen/native_parse.py
index c64b6a0..797afee 100644
--- a/aten/src/ATen/native_parse.py
+++ b/aten/src/ATen/native_parse.py
@@ -38,6 +38,11 @@
arguments = []
python_default_inits = func_decl.get('python_default_init', {})
is_out_fn = func_name.endswith('_out')
+ if is_out_fn and func_decl.get('variants', []) not in ['function', ['function']]:
+ raise RuntimeError("Native functions suffixed with _out MUST be declared with only the function variant; "
+ "e.g., variants: function; otherwise you will tickle a Python argument binding bug "
+ "(which usually manifests itself as the result variable being undefined.) "
+ "The culprit was: {}".format(func_name))
kwarg_only = False
# TODO: Use a real parser here; this will get bamboozled
