From 3f2efac95ef6575e33a7b4c9052d00afe1b83bad Mon Sep 17 00:00:00 2001
From: Joel Leitch <joel.leitch@gmail.com>
Date: Wed, 9 Jan 2013 23:37:38 +0000
Subject: [PATCH] Stop blowing up on a null key, but rather return that the
 element is not found.

---
 .../google/gson/internal/LinkedTreeMap.java    | 18 ++++++++++--------
 .../gson/internal/LinkedTreeMapTest.java       | 18 ++++++++++++++++++
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/gson/src/main/java/com/google/gson/internal/LinkedTreeMap.java b/gson/src/main/java/com/google/gson/internal/LinkedTreeMap.java
index cd2f4ca7..00672514 100644
--- a/gson/src/main/java/com/google/gson/internal/LinkedTreeMap.java
+++ b/gson/src/main/java/com/google/gson/internal/LinkedTreeMap.java
@@ -387,14 +387,16 @@ public class LinkedTreeMap<K extends Comparable<K>, V>
   }
 
   private TreeNode<K, V> find(K key) {
-    for (TreeNode<K, V> entry = root; entry != null; ) {
-      int compareVal = key.compareTo(entry.key);
-      if (compareVal < 0) {
-        entry = entry.left;
-      } else if (compareVal > 0) {
-        entry = entry.right;
-      } else {
-        return entry;
+    if (key != null) {
+      for (TreeNode<K, V> entry = root; entry != null; ) {
+        int compareVal = key.compareTo(entry.key);
+        if (compareVal < 0) {
+          entry = entry.left;
+        } else if (compareVal > 0) {
+          entry = entry.right;
+        } else {
+          return entry;
+        }
       }
     }
     return null;
diff --git a/gson/src/test/java/com/google/gson/internal/LinkedTreeMapTest.java b/gson/src/test/java/com/google/gson/internal/LinkedTreeMapTest.java
index 538ee5f4..a46d2b90 100644
--- a/gson/src/test/java/com/google/gson/internal/LinkedTreeMapTest.java
+++ b/gson/src/test/java/com/google/gson/internal/LinkedTreeMapTest.java
@@ -56,6 +56,24 @@ public class LinkedTreeMapTest extends TestCase {
     assertEquals(map.size(), map.entrySet().size());
   }
 
+  public void testGetAndContainsNullKey() throws Exception {
+    LinkedTreeMap<String, Integer> map = new LinkedTreeMap<String, Integer>();
+    assertFalse(map.containsKey(null));
+    assertNull(map.get(null));
+
+    map.put("A", 1);
+    assertFalse(map.containsKey(null));
+    assertNull(map.get(null));
+  }
+
+  public void testDisallowPutForNullKeys() throws Exception {
+    LinkedTreeMap<String, Integer> map = new LinkedTreeMap<String, Integer>();
+    try {
+      map.put(null, 1);
+      fail();
+    } catch (NullPointerException expected) {}
+  }
+
   public void testSingleElement() throws Exception {
     LinkedTreeMap<String, Integer> map = new LinkedTreeMap<String, Integer>();
     map.put("A", 1);