Merge pull request #195 from lorentey/fix-bitset-shrinking-issue

[BitSet] Fix invariant violation in member subscript
apple · Oct 9, 2022 · d05cba0 · d05cba0
2 parents 92210c5 + 1b71d2c
commit d05cba0
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Showing 2 changed files with 8 additions and 8 deletions.
diff --git a/Sources/BitCollections/BitSet/BitSet+Extras.swift b/Sources/BitCollections/BitSet/BitSet+Extras.swift
@@ -70,7 +70,9 @@ extension BitSet {
       } else if member > _capacity {
         return
       }
-      _update { handle in handle[member: member] = newValue }
+      _updateThenShrink { handle, shrink in
+        shrink = handle.update(member, to: newValue)
+      }
     }
   }
 

diff --git a/Sources/BitCollections/BitSet/BitSet._UnsafeHandle.swift b/Sources/BitCollections/BitSet/BitSet._UnsafeHandle.swift
@@ -189,13 +189,11 @@ extension BitSet._UnsafeHandle {
     return _mutableWords[index.word].remove(index.bit)
   }
 
-  subscript(member member: UInt) -> Bool {
-    get { contains(member) }
-    set {
-      ensureMutable()
-      let (w, b) = _BitPosition(member).split
-      _mutableWords[w].update(b, to: newValue)
-    }
+  internal mutating func update(_ member: UInt, to newValue: Bool) -> Bool {
+    ensureMutable()
+    let (w, b) = _BitPosition(member).split
+    _mutableWords[w].update(b, to: newValue)
+    return w == _words.count &- 1
   }
 }