[patch net-next] tools: ynl: fix attr_space variable to exist even if processing unknown attribute

[Jiri Pirko <jiri@resnulli.us>]

From: Jiri Pirko <jiri@nvidia.com>

If message contains unknown attribute and user passes
"--process-unknown" command line option, _decode() gets called with space
arg set to None. In that case, attr_space variable is not initialized
used which leads to following trace:

Traceback (most recent call last):
  File "./tools/net/ynl/cli.py", line 77, in <module>
    main()
  File "./tools/net/ynl/cli.py", line 68, in main
    reply = ynl.dump(args.dump, attrs)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "tools/net/ynl/lib/ynl.py", line 909, in dump
    return self._op(method, vals, [], dump=True)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "tools/net/ynl/lib/ynl.py", line 894, in _op
    rsp_msg = self._decode(decoded.raw_attrs, op.attr_set.name)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "tools/net/ynl/lib/ynl.py", line 639, in _decode
    self._rsp_add(rsp, attr_name, None, self._decode_unknown(attr))
                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "tools/net/ynl/lib/ynl.py", line 569, in _decode_unknown
    return self._decode(NlAttrs(attr.raw), None)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "tools/net/ynl/lib/ynl.py", line 630, in _decode
    search_attrs = SpaceAttrs(attr_space, rsp, outer_attrs)
                              ^^^^^^^^^^
UnboundLocalError: cannot access local variable 'attr_space' where it is not associated with a value

Fix this by setting attr_space to None in case space is arg None.

Fixes: bf8b832374fb ("tools/net/ynl: Support sub-messages in nested attribute spaces")
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
 tools/net/ynl/lib/ynl.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/net/ynl/lib/ynl.py b/tools/net/ynl/lib/ynl.py
index 03c7ca6aaae9..b16d24b7e288 100644
--- a/tools/net/ynl/lib/ynl.py
+++ b/tools/net/ynl/lib/ynl.py
@@ -588,10 +588,12 @@ class YnlFamily(SpecFamily):
         return decoded
 
     def _decode(self, attrs, space, outer_attrs = None):
+        rsp = dict()
         if space:
             attr_space = self.attr_sets[space]
-        rsp = dict()
-        search_attrs = SpaceAttrs(attr_space, rsp, outer_attrs)
+            search_attrs = SpaceAttrs(attr_space, rsp, outer_attrs)
+        else:
+            search_attrs = None
 
         for attr in attrs:
             try:
-- 
2.43.0