This variable used in the error path was not defined according to Ruff.
msg_format.attr_set is used instead, presumably the one that was
supposed to be used originally.

This is linked to Ruff error F821 [1]:

  An undefined name is likely to raise NameError at runtime.

Fixes: 1769e2be4baa ("tools/net/ynl: Add 'sub-message' attribute decoding to ynl")
Link: https://docs.astral.sh/ruff/rules/undefined-name/ [1]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Notes: I don't know if such fix can be queued to 'net'. It is in the
error path, it doesn't seem required to backport it.
---
 tools/net/ynl/pyynl/lib/ynl.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/net/ynl/pyynl/lib/ynl.py b/tools/net/ynl/pyynl/lib/ynl.py
index 8244a5f440b2be8f08f8424270a4dbd67a81a80d..15ddb0b1adb63f5853bf58579687d160a9c46860 100644
--- a/tools/net/ynl/pyynl/lib/ynl.py
+++ b/tools/net/ynl/pyynl/lib/ynl.py
@@ -746,7 +746,7 @@ class YnlFamily(SpecFamily):
                 subdict = self._decode(NlAttrs(attr.raw, offset), msg_format.attr_set)
                 decoded.update(subdict)
             else:
-                raise Exception(f"Unknown attribute-set '{attr_space}' when decoding '{attr_spec.name}'")
+                raise Exception(f"Unknown attribute-set '{msg_format.attr_set}' when decoding '{attr_spec.name}'")
         return decoded
 
     def _decode(self, attrs, space, outer_attrs = None):

-- 
2.51.0