Wait for jobs to complete when resolving the classpaths

[jdneo]

When I'm working for this PR: redhat-developer/vscode-java#1484, I found that the test case getClasspath will randomly fail, see: https://travis-ci.org/github/redhat-developer/vscode-java/jobs/697117335

It's because if we try to get the classpath when the m2e is updating the projects, the return results might only contain the source classes without dependency jars. so I add a wait here.

Signed-off-by: Sheng Chen sheche@microsoft.com

[fbricon]

That's too broad. You'll wait for unrelated jobs to finish

[jdneo]

Can I narrow to:

JobHelpers.waitForJobs(IConstants.UPDATE_PROJECT_FAMILY, new NullProgressMonitor());
JobHelpers.waitForBuildJobs(10 * 1000);

Also wait for build jobs since update request will also trigger a clean build in MavenBuilder. But return the result no matter build finishes or not after 10 secs.

[fbricon]

I don't think you need to wait for build jobs. During a build all the classpaths are supposed to have been set already, so building projects won't change anything to that

[jdneo]

Yes you are right. I found out that the case will fail after the invocation of JavaCore.setClasspathContainer(), which will trigger SetContainerOperation

I'm deciding to add following code:

IWorkspace workspace = ResourcesPlugin.getWorkspace();
workspace.run(new IWorkspaceRunnable() {
    @Override
        public void run(IProgressMonitor monitor) {
    }
}, workspace.getRoot(), 0, new NullProgressMonitor());

to wait for it. (JavaModeChangeOperation will lock the workspace tree). Does this make sense?

[fbricon]

@snjeza your opinion on that?

[jdneo]

Just add more background here: The cases might fail with a very high possibility after BuildPathManager#mavenProjectChanged(), where the SetContainerOperation will be triggered.

[snjeza]

you can try

IWorkspace workspace = ResourcesPlugin.getWorkspace();
workspace.run(new IWorkspaceRunnable() {
    @Override
        public void run(IProgressMonitor monitor) {
    }
}, workspace.getRoot(), IWorkspace.AVOID_UPDATE, new NullProgressMonitor());

[fbricon]

move out of loop

[jdneo]

Just came up in mind that maybe implement by this way will have much less impact on the perf?

IWorkspace workspace = ResourcesPlugin.getWorkspace();
ISchedulingRule currentRule = Job.getJobManager().currentRule();
ISchedulingRule schedulingRule;
if (currentRule != null && currentRule.contains(javaProject.getSchedulingRule())) {
	schedulingRule = null;
} else {
	schedulingRule = javaProject.getSchedulingRule();
}
workspace.run(new IWorkspaceRunnable() {
	@Override
	public void run(IProgressMonitor monitor) throws CoreException {
		// get classpath
	}
}, schedulingRule, IWorkspace.AVOID_UPDATE, new NullProgressMonitor());

[fbricon]

Thanks @jdneo !