[cp-patches] [RFC/PATCH] Fix NPE in HashMap.put()

[Pekka Enberg]

Stefan Ring reports that commit f154af6 ("Fix HashMap.put() to check for
hashCode equality before equals()") breaks running the CACAO test suite for me.
It looks like this:

  LD_LIBRARY_PATH=../../../src/cacao/.libs ../../../src/cacao/cacao 
-Xbootclasspath:../../../src/classes/classes:/home/sr/classpathcvs/share/classpath/glibj.zip
 -classpath /usr/share/java/junit4.jar:. org.junit.runner.JUnitCore All
  JUnit version 4.5
  .E
  Time: 0.003
  There was 1 failure:
  1) initializationError(All)
  java.lang.NullPointerException
     at java.util.HashMap.put(HashMap.java:348)
     at java.util.HashSet.add(HashSet.java:151)
     at org.junit.runners.model.RunnerBuilder.addParent(RunnerBuilder.java:64)
     at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:81)
     at org.junit.runners.Suite.<init>(Suite.java:88)
     at org.junit.runners.Suite.<init>(Suite.java:54)
     at java.lang.reflect.VMConstructor.construct(Native Method)
     at java.lang.reflect.Constructor.newInstance(Constructor.java:318)
     at 
org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:35)
     at 
org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:24)
     at 
org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:57)
     at 
org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:29)
     at 
org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:57)
     at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:93)
     at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:84)
     at org.junit.runners.Suite.<init>(Suite.java:66)
     at org.junit.runner.Request.classes(Request.java:68)
     at org.junit.runner.JUnitCore.run(JUnitCore.java:107)
     at org.junit.runner.JUnitCore.runMain(JUnitCore.java:88)
     at org.junit.runner.JUnitCore.runMainAndExit(JUnitCore.java:54)
     at org.junit.runner.JUnitCore.main(JUnitCore.java:46)

  FAILURES!!!
  Tests run: 1,  Failures: 1

Looking at the code, it's obviously broken for HashMap.put() with a null key.

Signed-off-by: Pekka Enberg <penb...@kernel.org>
---
 java/util/HashMap.java |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/java/util/HashMap.java b/java/util/HashMap.java
index 9d64fec..4e92731 100644
--- a/java/util/HashMap.java
+++ b/java/util/HashMap.java
@@ -345,7 +345,10 @@ public class HashMap<K, V> extends AbstractMap<K, V>
 
     while (e != null)
       {
-        if ((key.hashCode() == e.key.hashCode()) && equals(key, e.key))
+        int hash1 = key == null ? 0 : key.hashCode();
+        int hash2 = e.key == null ? 0 : e.key.hashCode();
+
+        if ((hash1 == hash2) && equals(key, e.key))
           {
             e.access(); // Must call this for bookkeeping in LinkedHashMap.
             V r = e.value;
-- 
1.7.6.4