Merge pull request #3620 from msavitskiy/1.x

1.x: Fix NPE in CompositeException when nested throws on initCause

Author: akarnokd

src/main/java/rx/exceptions/CompositeException.java

@@ -118,12 +118,13 @@ public synchronized Throwable getCause() {
                 // we now have 'e' as the last in the chain
                 try {
                     chain.initCause(e);
+                    chain = chain.getCause();
                 } catch (Throwable t) {
                     // ignore
                     // the javadocs say that some Throwables (depending on how they're made) will never
                     // let me call initCause without blowing up even if it returns null
+                    chain = e;
                 }
-                chain = chain.getCause();
             }
             cause = _cause;
         }

src/test/java/rx/exceptions/CompositeExceptionTest.java

@@ -178,4 +178,46 @@ public void testNullElement() {
         composite.getCause();
         composite.printStackTrace();
     }
+
+    @Test(timeout = 1000)
+    public void testCompositeExceptionWithUnsupportedInitCause() {
+        Throwable t = new Throwable() {
+            @Override
+            public synchronized Throwable initCause(Throwable cause) {
+                throw new UnsupportedOperationException();
+            }
+        };
+        CompositeException cex = new CompositeException(Arrays.asList(t, ex1));
+
+        System.err.println("----------------------------- print composite stacktrace");
+        cex.printStackTrace();
+        assertEquals(2, cex.getExceptions().size());
+
+        assertNoCircularReferences(cex);
+        assertNotNull(getRootCause(cex));
+
+        System.err.println("----------------------------- print cause stacktrace");
+        cex.getCause().printStackTrace();
+    }
+
+    @Test(timeout = 1000)
+    public void testCompositeExceptionWithNullInitCause() {
+        Throwable t = new Throwable("ThrowableWithNullInitCause") {
+            @Override
+            public synchronized Throwable initCause(Throwable cause) {
+                return null;
+            }
+        };
+        CompositeException cex = new CompositeException(Arrays.asList(t, ex1));
+
+        System.err.println("----------------------------- print composite stacktrace");
+        cex.printStackTrace();
+        assertEquals(2, cex.getExceptions().size());
+
+        assertNoCircularReferences(cex);
+        assertNotNull(getRootCause(cex));
+
+        System.err.println("----------------------------- print cause stacktrace");
+        cex.getCause().printStackTrace();
+    }
 }