Fix another exception related to inferred spans (#1232)

closes #1229

Author: felixbarny

apm-agent-core/src/main/java/co/elastic/apm/agent/collections/LongList.java

@@ -27,6 +27,7 @@
 import java.util.Arrays;
 
 public class LongList {
+    private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
     private static final int DEFAULT_CAPACITY = 16;
     private long[] longs;
     private int size;
@@ -58,9 +59,20 @@ public void addAll(LongList other) {
         size += other.size;
     }
 
-    private void ensureCapacity(int size) {
-        if (longs.length < size) {
-            longs = Arrays.copyOf(longs, longs.length * 2);
+    private void ensureCapacity(long minCapacity) {
+        if (longs.length < minCapacity) {
+            longs = Arrays.copyOf(longs, newCapacity(minCapacity, longs.length));
+        }
+    }
+
+    static int newCapacity(long minCapacity, long oldCapacity) {
+        long growBy50Percent = oldCapacity + (oldCapacity >> 1);
+        if (minCapacity <= growBy50Percent) {
+            return (int) growBy50Percent;
+        } else if (minCapacity <= MAX_ARRAY_SIZE) {
+            return (int) minCapacity;
+        } else {
+            throw new OutOfMemoryError();
         }
     }
 

apm-agent-core/src/test/java/co/elastic/apm/agent/collections/LongListTest.java

@@ -69,6 +69,28 @@ void testAddAll() {
         assertThat(this.longList.get(2)).isEqualTo(44);
     }
 
+    @Test
+    void testAddAllLargeList() {
+        longList.add(42);
+        LongList list2 = new LongList();
+        for (int i = 0; i < 42; i++) {
+            list2.add(i);
+        }
+        longList.addAll(list2);
+        assertThat(this.longList.getSize()).isEqualTo(43);
+        assertThat(this.longList.get(0)).isEqualTo(42);
+        assertThat(this.longList.get(1)).isEqualTo(0);
+        assertThat(this.longList.get(2)).isEqualTo(1);
+    }
+
+    @Test
+    void testNewCapacity() {
+        assertThat(LongList.newCapacity(1, 0)).isEqualTo(1);
+        assertThat(LongList.newCapacity(42, 4)).isEqualTo(42);
+        assertThat(LongList.newCapacity(5, 4)).isEqualTo(6);
+        assertThatThrownBy(() -> LongList.newCapacity(Integer.MAX_VALUE, 4)).isInstanceOf(OutOfMemoryError.class);
+    }
+
     @Test
     void testOutOfBounds() {
         assertThatThrownBy(() -> longList.get(0)).isInstanceOf(IndexOutOfBoundsException.class);