Have a strange problem in the Redmine issues import plugin.

I'm getting below exception when trying to import Redmine versions into OneDev milestones. It occurs when invoking oneDevProject.getMilestones() (at this line)

Importing versions from project test:3...
org.hibernate.LazyInitializationException: could not initialize proxy [io.onedev.server.model.Project#2] - no Session
    	at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:170)
    	at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:310)
    	at org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor.intercept(ByteBuddyInterceptor.java:45)
    	at org.hibernate.proxy.ProxyConfiguration$InterceptorDispatcher.intercept(ProxyConfiguration.java:95)
    	at io.onedev.server.model.Project$HibernateProxy$svxUXFpq.getMilestones(Unknown Source)
    	at com.devcharly.onedev.plugin.imports.redmine.ImportUtils.importVersions(ImportUtils.java:1097)
    	at com.devcharly.onedev.plugin.imports.redmine.RedmineIssueImporter.doImport(RedmineIssueImporter.java:33)
    	at com.devcharly.onedev.plugin.imports.redmine.RedmineIssueImporter.doImport(RedmineIssueImporter.java:1)
    	at io.onedev.server.web.page.project.issues.imports.IssueImportPage$1.doImport(IssueImportPage.java:67)
    	at io.onedev.server.web.component.imports.ImportPanel$4$1.call(ImportPanel.java:170)
    	at io.onedev.server.web.component.imports.ImportPanel$4$1.call(ImportPanel.java:166)
    	at io.onedev.server.persistence.DefaultTransactionManager$1.call(DefaultTransactionManager.java:72)
    	at io.onedev.server.persistence.DefaultSessionManager.call(DefaultSessionManager.java:79)
    	at io.onedev.server.persistence.DefaultTransactionManager.call(DefaultTransactionManager.java:60)
    	at io.onedev.server.web.component.imports.ImportPanel$4.runTask(ImportPanel.java:166)
    	at io.onedev.server.web.component.taskbutton.TaskButton$2.call(TaskButton.java:173)
    	at io.onedev.server.web.component.taskbutton.TaskButton$2.call(TaskButton.java:144)
    	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    	at io.onedev.server.security.SecurityUtils$1.run(SecurityUtils.java:338)
    	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    	at java.lang.Thread.run(Thread.java:748)

It turns out that following Redmine import options cause the problem:

If I remove them all (using the trash icons), then it works without any exception.

The source code for this options is copied from other import plugins. It is here: IssueTrackerMapping and IssuePriorityMapping

The exception occurs only when importing milestones. Importing Redmine issues works.

Maybe you can reproduce the problem with the Jira import plugin because it also has a class IssuePriorityMapping. Try adding a call to oneDevProject.getMilestones() to io.onedev.server.plugin.imports.jiracloud.ImportUtils.importIssues().

Or use the Redmine plugin: https://github.com/DevCharly/onedev-plugin-import-redmine

On the Redmine import options page enable Import Versions and disable Import Issues:

Hope you can help. I have no idea what's wrong.... Thanks.