# UNDF: UNDF-2026-000000233
Fixes pyramid-0003: config/actions.py resolveConflicts() — list.remove() inside sorted output loop.

--- a/src/pyramid/config/actions.py
+++ b/src/pyramid/config/actions.py

@@ DEFECT pyramid-0003: resolveConflicts() line 490

 # In class _ConflictState.__init__():
-    self.remaining_actions = []             # list — O(n) remove — CWE-407
+    self.remaining_actions = []             # kept as list for extend/iteration
+    self.remaining_actions_set = set()      # FIX pyramid-0003: O(1) removal

 # In normalize_actions / state initialization:
     state.remaining_actions.extend(normalize_actions(actions))
+    state.remaining_actions_set.update(id(a) for a in state.remaining_actions)

 # In resolveConflicts() yield loop:
     for i, action in sorted(output, key=operator.itemgetter(0)):
         state.min_order = action['order']
         state.start = i + 1
-        state.remaining_actions.remove(action)    # O(n) linear scan — CWE-407
+        state.remaining_actions_set.discard(id(action))   # O(1) — fixed
+        # remaining_actions list lazily filtered when iterated (or rebuild on demand)
         state.resolved_ainfos[action['discriminator']] = (i, action)
         yield action

# NOTE: actions are dicts (unhashable), so we track by id(). The list is
# kept for ordered iteration in subsequent passes; rebuild by filtering with
# the set when needed: [a for a in state.remaining_actions if id(a) in set].
# This converts the O(N²) startup cost to O(N).