NPE just causes a log message

[GerdP]

While working on a patch for the reverter plugin I noticed this log message

2019-03-26 08:54:08.204 SEVERE: Thread main-worker-0 raised java.lang.NullPointerException

There is no hint in the dialog and no traceback in the log explaining what went wrong. With this small hack I can reproduce the problem easily.

src/reverter/DataSetCommandMerger.java

@@ -106 +106 @@
 
         List<Node> newNodes = new ArrayList<>(source.getNodesCount());
         for (Node sourceNode : source.getNodes()) {
+               if (true) sourceNode = null;
             Node targetNode = (Node) getMergeTarget(sourceNode);
             // Target node is not deleted or it will be undeleted when running existing commands
             if (!targetNode.isDeleted() || nominalRevertedPrimitives.contains(targetNode)) {

[GerdP]

If I got that right this is a potential problem in all routines which override PleaseWaitRunnable.realRun() without a proper try/catch block using

                // Exception has to thrown in EDT to be shown to user
                SwingUtilities.invokeLater(() -> {
                    if (e instanceof RuntimeException) {
                        BugReportExceptionHandler.handleException(e);
                    } else {
                        ExceptionDialogUtil.explainException(e);
                    }
                });

[GerdP]

possible solution for reverter

[GerdP]

Sorry, I confused realRun() in reverter with doRealRun() in class PleaseWaitRunnable:

        } catch (final JosmRuntimeException | IllegalArgumentException | IllegalStateException | UnsupportedOperationException |
                OsmTransferException | IOException | SAXException | InvocationTargetException | InterruptedException e) {

So, we already have code to catch a lot of possible exceptions, but NullPointerException is not yet handled.
Not sure if it makes sense to catch all RunTimeExceptions or if NPE should be added to the above list?

[GerdP]

Regression of r11746?

[Don-vip]

likely. Maybe this commit wasn't a good idea after all. I'm OK to catch RuntimeException. Maybe PMD config must be tuned.

[GerdP]

In 14936/josm:

fix #17525: catch all RunTimeExceptions in PleaseWaitRunnable.doRealRun()