fixup! client: new root sigs only counted once per keyid

Author: joshuagl

tuf/client/updater.py

@@ -1385,7 +1385,7 @@ def _verify_root_self_signed(self, signable):
     signatures = signable['signatures']
     signed = securesystemslib.formats.encode_canonical(
         signable['signed']).encode('utf-8')
-    verified_sig_keyids = []
+    verified_sig_keyids = set()
 
     for signature in signatures:
       keyid = signature['keyid']
@@ -1403,12 +1403,9 @@ def _verify_root_self_signed(self, signable):
       valid_sig = securesystemslib.keys.verify_signature(key, signature, signed)
 
       if valid_sig:
-        verified_sig_keyids.append(keyid)
+        verified_sig_keyids.add(keyid)
 
-    # A signature with a given keyid should only count towards the threshold
-    # once. Convert the list of keyids into a set, in order to uniquify them
-    # and therefore count each keyid only once towards the threshold.
-    if len(set(verified_sig_keyids)) >= threshold:
+    if len(verified_sig_keyids) >= threshold:
       return True
     return False