[Heap] bubbleUp: remove @_effects attribute

This reintroduces retain/release operations for the empty array until swiftlang/swift#38898 lands.

Mitigate the performance costs of this by refactoring code to reduce the size of the inlined bubbleUpMin/Max invocations.

Author: lorentey

Sources/PriorityQueueModule/Heap+UnsafeHandle.swift

@@ -91,66 +91,20 @@ extension Heap._UnsafeHandle {
 }
 
 extension Heap._UnsafeHandle {
-  // Note: the releasenone annotation here tells the compiler that this function
-  // will not release any strong references, so it doesn't need to worry about
-  // retaining things. This is true in the sense that `bubbleUp` just reorders
-  // storage contents, but it does call `Element.<`, which we cannot really
-  // promise anything about -- it may release things!
-  //
-  // FWIW, I think `Element`'s Comparable implementation can only cause the
-  // heap's storage to be released if it included an exclusivity violation --
-  // `bubbleUp` is only ever called from mutating heap members, after all.
-  // So if there is an issue, I think it would be triggered by the `Comparable`
-  // implementation releasing something inside `Element`, and/or by the
-  // `releasenone` annotation here having an effect in client code that called
-  // into `Heap`.
-  @_effects(releasenone)
   @inlinable
   internal func bubbleUp(_ node: _Node) {
-    if node.isRoot {
-      // We're can't go any further
-      return
-    }
-    let parent = node.parent()
+    guard !node.isRoot else { return }
 
-    if node.isMinLevel {
-      if self[node] > self[parent] {
-        swapAt(node, parent)
-        bubbleUpMax(parent)
-      } else {
-        bubbleUpMin(node)
-      }
-    } else {
-      if self[node] < self[parent] {
-        swapAt(node, parent)
-        bubbleUpMin(parent)
-      } else {
-        bubbleUpMax(node)
-      }
-    }
-  }
+    let parent = node.parent()
 
-  @_effects(releasenone)
-  @inline(__always)
-  @inlinable
-  internal func bubbleUpMin(_ node: _Node) {
     var node = node
-
-    while let grandparent = node.grandParent(),
-          self[node] < self[grandparent] {
-      swapAt(node, grandparent)
-      node = grandparent
+    if node.isMinLevel == (self[node] > self[parent]) {
+      swapAt(node, parent)
+      node = parent
     }
-  }
-
-  @_effects(releasenone)
-  @inline(__always)
-  @inlinable
-  internal func bubbleUpMax(_ node: _Node) {
-    var node = node
 
     while let grandparent = node.grandParent(),
-          self[node] > self[grandparent] {
+          node.isMinLevel == (self[node] < self[grandparent]) {
       swapAt(node, grandparent)
       node = grandparent
     }