Do not init Java exception cause if it has already been set.

For #4699.
jruby · Aug 30, 2017 · b1c6c38 · b1c6c38
1 parent c77d3de
commit b1c6c38
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/core/src/main/java/org/jruby/RubyKernel.java b/core/src/main/java/org/jruby/RubyKernel.java
@@ -904,7 +904,7 @@ private static void maybeRaiseJavaException(final Ruby runtime,
                 if (ex.getCause() == null && cause instanceof ConcreteJavaProxy) {
                     // allow raise java.lang.RuntimeException.new, cause: myCurrentException()
                     maybeThrowable = ((ConcreteJavaProxy) cause).getObject();
-                    if (maybeThrowable instanceof Throwable && ex != maybeThrowable) {
+                    if (maybeThrowable instanceof Throwable && ex != maybeThrowable && ex.getCause() == null) {
                         ex.initCause((Throwable) maybeThrowable);
                     }
                 }