tools: ynl: rework policy access to support recursion

Donald points out that the current naive implementation using dicts
breaks if policy is recursive (child nest uses policy idx already
used by its parent).

Lean more into the NlPolicy class. This lets us "render" the policy
on demand, when user accesses it. If someone wants to do an infinite
walk that's on them :) Show policy info as attributes of the class
and use dict format to descend into sub-policies for extra neatness.

Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20260313232047.2068518-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 11 insertions, 15 deletions

diff --git a/tools/testing/selftests/net/nl_nlctrl.py b/tools/testing/selftests/net/nl_nlctrl.py
index d19e206c2c02..fe1f66dc9435 100755
--- a/tools/testing/selftests/net/nl_nlctrl.py
+++ b/tools/testing/selftests/net/nl_nlctrl.py
@@ -68,39 +68,35 @@ def getpolicy_dump(_ctrl) -> None:
     # dev-get: do has a real policy with ifindex, dump has no policy
     # (only the reject-all policy with maxattr=0)
     pol = ndev.get_policy('dev-get', 'do')
-    ksft_in('ifindex', pol.attrs,
-            comment="dev-get do policy should have ifindex")
-    ksft_eq(pol.attrs.get('ifindex', {}).get('type'), 'u32')
+    ksft_in('ifindex', pol, comment="dev-get do policy should have ifindex")
+    ksft_eq(pol['ifindex'].type, 'u32')
 
     pol_dump = ndev.get_policy('dev-get', 'dump')
-    ksft_eq(len(pol_dump.attrs), 0,
-            comment="dev-get should not accept any attrs")
+    ksft_eq(len(pol_dump), 0, comment="dev-get should not accept any attrs")
 
     # napi-get: both do and dump have real policies
     pol_do = ndev.get_policy('napi-get', 'do')
-    ksft_ge(len(pol_do.attrs), 1)
+    ksft_ge(len(pol_do), 1)
 
     pol_dump = ndev.get_policy('napi-get', 'dump')
-    ksft_ge(len(pol_dump.attrs), 1)
+    ksft_ge(len(pol_dump), 1)
 
     # -- ethtool (full ops) --
     et = EthtoolFamily()
 
     # strset-get (has both do and dump, full ops share policy)
     pol_do = et.get_policy('strset-get', 'do')
-    ksft_ge(len(pol_do.attrs), 1, comment="strset-get should have a do policy")
+    ksft_ge(len(pol_do), 1, comment="strset-get should have a do policy")
 
     pol_dump = et.get_policy('strset-get', 'dump')
-    ksft_ge(len(pol_dump.attrs), 1,
-            comment="strset-get should have a dump policy")
+    ksft_ge(len(pol_dump), 1, comment="strset-get should have a dump policy")
 
     # Same policy means same attribute names
-    ksft_eq(set(pol_do.attrs.keys()), set(pol_dump.attrs.keys()))
+    ksft_eq(set(pol_do.keys()), set(pol_dump.keys()))
 
     # linkinfo-set is do-only (SET command), no dump
     pol_do = et.get_policy('linkinfo-set', 'do')
-    ksft_ge(len(pol_do.attrs), 1,
-            comment="linkinfo-set should have a do policy")
+    ksft_ge(len(pol_do), 1, comment="linkinfo-set should have a do policy")
 
     pol_dump = et.get_policy('linkinfo-set', 'dump')
     ksft_eq(pol_dump, None,
@@ -113,9 +109,9 @@ def getpolicy_by_op(_ctrl) -> None:
 
     # dev-get do policy should have named attributes from the spec
     pol = ndev.get_policy('dev-get', 'do')
-    ksft_ge(len(pol.attrs), 1)
+    ksft_ge(len(pol), 1)
     # All attr names should be resolved (no 'attr-N' fallbacks)
-    for name in pol.attrs:
+    for name in pol:
         ksft_true(not name.startswith('attr-'),
                   comment=f"unresolved attr name: {name}")