jmx-dev [PATCH] JDK-8005472: com/sun/jmx/remote/NotificationMarshalVersions/TestSerializationMismatch.sh failed on windows (original) (raw)

Jaroslav Bachorik jaroslav.bachorik at oracle.com
Tue Feb 5 06:40:26 PST 2013

Updates in http://cr.openjdk.java.net/~jbachorik/8005472/webrev.05

Comments inline

On 01/10/2013 10:44 PM, Stuart Marks wrote:

On 1/10/13 7:20 AM, Jaroslav Bachorik wrote:

Update: http://cr.openjdk.java.net/~jbachorik/8005472/webrev.04 Thanks for the update. Note, argv[0] is used before argv.length is checked, so if no args are passed this gives index out of bounds instead of the usage message.

It's gone. Shouldn't have been left there anyway.

I see you take pains to write and flush the URL to stdout before writing the signaling file. Good. The obvious alternative (which I started writing but then erased) is just to put the URL into the signaling file. But this has a race between creation of the file and the writing of its contents. So, what you have works. (This kind of rendezvous problem occurs a lot; it seems like there ought to be a simpler way.) I suspect the -e option caused hangs because if something failed, it would leave the server running, spoiling the next test run. The usual way to deal with this is to use the shell 'trap' statement, to kill subprocesses and remove temp files before exiting the shell. Probably a good practice in general, but perhaps too much shell hackery for this change. (Up to you if you want to tackle it.)

I would rather not ...

Regarding how the test is detecting success/failure, the concern is that if the client fails for some reason other than the failure being checked for, the test will still report passing. Since the error message is coming out of the client JVM, in principle it ought to be possible to redirect it somehow in order to do the assertion checking in Java. With the current shell scheme, not only are other failures reported as the test passing, these other failures are erased in the grep pipeline, so they're not even visible in the test log.

I've changed the logic slightly to check for the java process exit status as well as for the presence of the trigger text in the process output. This should catch all the regular failures.

Unfortunately, the way the notification handling is implemented now it is not really possible to check for the error from within the application - the error state is captured by the *NotificationForwarder class and only reported to the logger.

-JB-

This last issue is rather far afield from this webrev, and fixing it will probably require some rearchitecting of the test. So maybe it should be considered independently. I just happened to notice this going on, and I noticed the similarity to what's going on in the RMI tests. s'marks

On 01/10/2013 09:52 AM, Stuart Marks wrote: On 1/7/13 3:23 AM, Jaroslav Bachorik wrote: On 01/04/2013 11:37 PM, Kelly O'Hair wrote: I suspect it is not hanging because it does not exist, but that some other windows process has it's hands on it. This is the stdout file from the server being started up right? Could the server from a previous test run be still running?

Exactly. Amy confirmed this and provided a patch which resolves the hanging problem. The update patch is at http://cr.openjdk.java.net/~jbachorik/8005472/webrev.01 Hi Jaroslav, The change to remove the parentheses from around the server program looks right. It avoids forking an extra process (at least in some shells) and lets $! refer to the actual JVM, not an intermediate shell process. The rm -f from Kelly's suggestion is good too. But there are other things wrong with the script. I don't think they could cause hanging, but they could cause the script to fail in unforeseen ways, or even to report success incorrectly. One problem is introduced by the change, where the Server's stderr is also redirected into $URLPATH along with stdout. This means that if the Server program reports any errors, they'll get mixed into the URLPATH file instead of appearing in the test log. The URLPATH file's contents is never reported, so these error messages will be invisible. Fixed, only the stdout is redirected to $URLPATH. The exit status of some of the critical commands (such as the compilations) isn't checked, so if javac fails for some reason, the test might not report failure. Instead, some weird error might or might not be reported later (though one will still see the javac errors in the log). Fixed, introduced the check. The "set -e" was hanging the script so I have to check for the exit status manually. I don't think the sleep at line 80 is necessary, since the client runs synchronously and should have exited by this point. And it's gone. The wait loop checking for the existence of the URLPATH file doesn't actually guarantee that the server is running or has initialized yet. The file is actually created by the shell before the Server JVM starts up. Thus, runClient might try to read from it before the server has written anything to it. Or, as mentioned above, the server might have written some error messages into the URLPATH file instead of the expected contents. Thus, the contents of the JMXURL variable can quite possibly be incorrect. The err is not redirected to the file. A separate file is used to signal the availability of the server and that file is created from the java code after the server has been started. Also, the err and out streams are flushed to make sure the JMX URL makes it into the file. If this occurs, what will happen when the client runs? It may emit some error message, and this will be filtered out by the grep pipeline. Thus, HASERRORS might end up empty, and the test will report passing, even though everything has failed! Shouldn't happen with only the controlled stdout redirected to the file. For this changeset I'd recommend at a minimum removing the redirection of stderr to URLPATH. If the server fails we'll at least see errors in the test log. For checking the notification message, is there a way to modify the client to report an exit status or throw an exception? Throwing an exception from main() will exit the JVM with a nonzero status, so this can be checked more easily from the script. I think this is less error-prone than grepping the output for a specific error message. The test should fail if there is any error; it should not succeed if an expected error is absent. This is unfortunately not possible. The notification processing needs to be robust enough to prevent exiting JVM in cases like this. Therefore it only reports the problem, dumps the notification and carries on. The only place one can find something went wrong is the err stream. You might consider having jtreg build the client and server classes. This might simplify some of the setup. Also, jtreg is meticulous about aborting the test if any compilations fail, so it takes care of that for you. I need same name classes with incompatible code compiled to two different locations - client and server. I was not able to figure out how to use jtreg to accomplish that. -JB- It would be nice if there were a better way to have the client rendezvous with the server. I hate to suggest it, but sleeping unconditionally after starting the server is probably necessary. Anything more robust probably requires rearchitecting the test, though. Sorry to dump all this on you. But one of the shell-based RMI tests suffers from exactly the same pathologies. (I have yet to fix it.) Unfortunately, I believe that there are a lot of other shell-based tests in the test suite that have similar problems. The lesson here is that writing reliable shell tests is a lot harder than it seems. Thanks, s'marks

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