repoview: avoid processing the same rev twice in _getstatichidden

If a rev had multiple children, it would be added to the heap multiple times. We
now ensure it is added only once.

mercurial/repoview.py

@@ -43,6 +43,7 b' def _getstatichidden(repo):'
         heapq.heapify(heap)
         heappop = heapq.heappop
         heappush = heapq.heappush
+        seen = set() # no need to init it with heads, they have no children
         while heap:
             rev = -heappop(heap)
             # All children have been processed so at that point, if no children
@@ -54,8 +55,11 b' def _getstatichidden(repo):'
                 if blocker:
                     # If visible, ensure parent will be visible too
                     hidden.discard(parent)
-                # Skip nodes which are public (guaranteed to not be hidden)
-                if getphase(repo, rev):
+                # - Avoid adding the same revision twice
+                # - Skip nodes which are public (guaranteed to not be hidden)
+                pre = len(seen)
+                seen.add(parent)
+                if pre < len(seen) and getphase(repo, rev):
                     heappush(heap, -parent)
     return hidden