Bug in PersistentList - list is broken after removeAll call #92

Kotlin · Nov 30, 2020 · 304e8e7 · 304e8e7
1 parent b6885b3
commit 304e8e7
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Showing 2 changed files with 14 additions and 1 deletion.
diff --git a/core/commonMain/src/implementations/immutableList/PersistentVectorBuilder.kt b/core/commonMain/src/implementations/immutableList/PersistentVectorBuilder.kt
@@ -755,7 +755,7 @@ internal class PersistentVectorBuilder<E>(private var vector: PersistentList<E>,
         while (lastIndex shr rootShift == 0) {
             rootShift -= LOG_MAX_BUFFER_SIZE
             @Suppress("UNCHECKED_CAST")
-            newRoot = root[0] as Array<Any?>
+            newRoot = newRoot[0] as Array<Any?>
         }
         return nullifyAfter(newRoot, lastIndex, rootShift)
     }

diff --git a/core/commonTest/src/contract/list/ImmutableListTest.kt b/core/commonTest/src/contract/list/ImmutableListTest.kt
@@ -29,6 +29,19 @@ class ImmutableListTest {
 
     }
 
+    @Test
+    fun persistentListFails() {
+        var xs = persistentListOf(
+                *(1..1885).map { it }.toTypedArray()
+        )
+
+        xs = xs.removeAll(
+                (1..1837).map { it }
+        )
+
+        assertEquals((1838..1885).toList(), xs)
+    }
+
     @Test fun ofElements() {
         val list0 = listOf("a", "d", 1, null)
         val list1 = persistentListOf("a", "d", 1, null)