Print Java stacktrace of cause for wrapped Java exceptions.

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/control/TopLevelExceptionHandler.java

@@ -264,7 +264,12 @@ private static void printJavaStackTrace(PException e) {
             traceback = traceback.getNextChain();
         }
         if (traceback != null) {
-            traceback.getException().printStackTrace();
+            PException exception = traceback.getException();
+            if (exception.getCause() != null && exception.getCause().getStackTrace().length != 0) {
+                exception.getCause().printStackTrace();
+            } else {
+                exception.printStackTrace();
+            }
         }
     }
 

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/statement/ExceptionHandlingStatementNode.java

@@ -218,7 +218,7 @@ protected final PException wrapJavaExceptionIfApplicable(Throwable e) {
 
     @TruffleBoundary
     private static void moveTruffleStackTrace(Throwable e, PException pe) {
-        pe.initCause(e.getCause());
+        pe.initCause(e);
         // Host exceptions have their stacktrace already filled in, call this to set
         // the cutoff point to the catch site
         pe.getTruffleStackTrace();