Fix #877

Author: cowtowncoder

release-notes/VERSION

@@ -6,6 +6,7 @@ Project: jackson-databind
 
 2.7.8 (not yet released)
 
+#877: @JsonIgnoreProperties`: ignoring the "cause" property of `Throwable` on GAE
 #1359: Improve `JsonNode` deserializer to create `FloatNode` if parser supports
 #1362: ObjectReader.readValues()` ignores offset and length when reading an array
  (reported by wastevenson@github)

src/main/java/com/fasterxml/jackson/databind/deser/BeanDeserializerFactory.java

@@ -709,7 +709,15 @@ protected SettableBeanProperty constructSettableProperty(DeserializationContext
         AnnotatedMember mutator = propDef.getNonConstructorMutator();
 
         if (ctxt.canOverrideAccessModifiers()) {
-            mutator.fixAccess(ctxt.isEnabled(MapperFeature.OVERRIDE_PUBLIC_ACCESS_MODIFIERS));
+            // [databind#877]: explicitly prevent forced access to `cause` of `Throwable`;
+            // never needed and attempts may cause problems on some platforms.
+            // !!! NOTE: should be handled better for 2.8 and later
+            if ((mutator instanceof AnnotatedField)
+                    && "cause".equals(mutator.getName())) {
+                ;
+            } else {
+                mutator.fixAccess(ctxt.isEnabled(MapperFeature.OVERRIDE_PUBLIC_ACCESS_MODIFIERS));
+            }
         }
         // note: this works since we know there's exactly one argument for methods
         BeanProperty.Std property = new BeanProperty.Std(propDef.getFullName(),

src/main/java/com/fasterxml/jackson/databind/util/ClassUtil.java

@@ -773,26 +773,22 @@ public static void checkAndFixAccess(Member member, boolean force)
          *   always to make it accessible (latter because it will force
          *   skipping checks we have no use for...), so let's always call it.
          */
-        //if (!ao.isAccessible()) {
         try {
             if (force || 
                     (!Modifier.isPublic(member.getModifiers())
                             || !Modifier.isPublic(member.getDeclaringClass().getModifiers()))) {
                 ao.setAccessible(true);
             }
         } catch (SecurityException se) {
-            /* 17-Apr-2009, tatu: Related to [JACKSON-101]: this can fail on
-             *    platforms like EJB and Google App Engine); so let's
-             *    only fail if we really needed it...
-             */
+            // 17-Apr-2009, tatu: Related to [JACKSON-101]: this can fail on platforms like
+            // Google App Engine); so let's only fail if we really needed it...
             if (!ao.isAccessible()) {
                 Class<?> declClass = member.getDeclaringClass();
                 throw new IllegalArgumentException("Can not access "+member+" (from class "+declClass.getName()+"; failed to set access: "+se.getMessage());
             }
         }
-        //}
     }
-    
+
     /*
     /**********************************************************
     /* Enum type detection

src/test/java/com/fasterxml/jackson/databind/misc/AccessFixTest.java

@@ -0,0 +1,42 @@
+package com.fasterxml.jackson.databind.misc;
+
+import java.io.IOException;
+import java.security.Permission;
+
+import com.fasterxml.jackson.databind.*;
+
+// Test(s) to verify that forced access works as expected
+public class AccessFixTest extends BaseMapTest
+{
+    static class CauseBlockingSecurityManager
+        extends SecurityManager
+    {
+        @Override
+        public void checkPermission(Permission perm) throws SecurityException {
+            if ("suppressAccessChecks".equals(perm.getName())) {
+throw new SecurityException("Can not force permission: "+perm);
+            }
+        }
+    }
+
+    // [databind#877]: avoid forcing access to `cause` field of `Throwable`
+    // as it is never actually used (always call `initCause()` instead)
+    public void testCauseOfThrowableIgnoral() throws Exception
+    {
+        final SecurityManager origSecMan = System.getSecurityManager();
+        try {
+            System.setSecurityManager(new CauseBlockingSecurityManager());
+            _testCauseOfThrowableIgnoral();
+        } finally {
+            System.setSecurityManager(origSecMan);
+        }
+    }
+
+    private void _testCauseOfThrowableIgnoral() throws Exception
+    {
+        ObjectMapper mapper = new ObjectMapper();
+        mapper.disable(MapperFeature.OVERRIDE_PUBLIC_ACCESS_MODIFIERS);
+        IOException e = mapper.readValue("{}", IOException.class);
+        assertNotNull(e);
+    }
+}