Merge pull request #5124 from performantdata/bug/SI-9522

SI-9522 release key reference when deleting from OpenHashMap

1 files changed, 57 insertions, 1 deletions

diff --git a/test/junit/scala/collection/mutable/OpenHashMapTest.scala b/test/junit/scala/collection/mutable/OpenHashMapTest.scala
index 9b5c20e01a..b6cddf2101 100644
--- a/test/junit/scala/collection/mutable/OpenHashMapTest.scala
+++ b/test/junit/scala/collection/mutable/OpenHashMapTest.scala
@@ -4,6 +4,10 @@ import org.junit.Test
 import org.junit.Assert._
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
+import org.openjdk.jol.info.GraphLayout
+import org.openjdk.jol.info.GraphWalker
+import org.openjdk.jol.info.GraphVisitor
+import org.openjdk.jol.info.GraphPathRecord
 
 /** Tests for [[OpenHashMap]]. */
 @RunWith(classOf[JUnit4])
@@ -28,7 +32,13 @@ class OpenHashMapTest {
     val fieldMirror = mirror.reflect(m).reflectField(termSym)
 		*/
     // Use Java reflection instead for now.
-    val field = m.getClass.getDeclaredField("deleted")
+    val field =
+      try {  // Name may or not be mangled, depending on what the compiler authors are doing.
+        m.getClass.getDeclaredField("scala$collection$mutable$OpenHashMap$$deleted")
+      } catch {
+        case _: NoSuchFieldException =>
+          m.getClass.getDeclaredField("deleted")
+      }
     field.setAccessible(true)
 
     m.put(0, 0)
@@ -39,4 +49,50 @@ class OpenHashMapTest {
     // TODO assertEquals(0, fieldMirror.get.asInstanceOf[Int])
     assertEquals(0, field.getInt(m))
   }
+
+  /** Test that an [[OpenHashMap]] frees references to a deleted key (SI-9522). */
+  @Test
+  def freesDeletedKey {
+    import scala.language.reflectiveCalls
+
+    class MyClass {
+      override def hashCode() = 42
+    }
+
+    val counter = new GraphVisitor() {
+      private[this] var instanceCount: Int = _
+
+      def countInstances(obj: AnyRef) = {
+        instanceCount = 0
+        val walker = new GraphWalker(obj)
+        walker.addVisitor(this)
+        walker.walk
+        instanceCount
+      }
+
+      override def visit(record: GraphPathRecord) {
+        if (record.klass() == classOf[MyClass])  instanceCount += 1
+      }
+    }
+
+    val m = OpenHashMap.empty[MyClass, Int]
+    val obj = new MyClass
+    assertEquals("Found a key instance in the map before adding one!?", 0, counter.countInstances(m))
+    m.put(obj, 0)
+    assertEquals("There should be only one key instance in the map.", 1, counter.countInstances(m))
+    m.put(obj, 1)
+    assertEquals("There should still be only one key instance in the map.", 1, counter.countInstances(m))
+    m.remove(obj)
+    assertEquals("There should be no key instance in the map.", 0, counter.countInstances(m))
+
+    val obj2 = new MyClass
+    assertEquals("The hash codes of the test objects need to match.", obj.##, obj2.##)
+    m.put(obj, 0)
+    m.put(obj2, 0)
+    assertEquals("There should be two key instances in the map.", 2, counter.countInstances(m))
+    m.remove(obj)
+    assertEquals("There should be one key instance in the map.", 1, counter.countInstances(m))
+    m.remove(obj2)
+    assertEquals("There should be no key instance in the map.", 0, counter.countInstances(m))
+  }
 }