Max Spring discovered a stack overflow in http://jenkins.361315.n4.nabble.com/channel-example-and-plugin-classes-gives-ClassNotFoundException-td3756092.html that pointed this call into thread context classloader (TCL) as the culprit. Independently, Paul Sandoz discovered the same issue in our products. If TCL is another classloader that delegates to UberClassLoader (UCL), this code causes infinite recursion.
And moreover, given the goal of UCL, it seems wrong that this class is changing behaviour based on contextual information like TCL.
In looking at 4de81f1eb3, the change was introduced to make sure XStream unmarshalling invoked from Plugin.start() would see the classes in that plugin. This was an issue back then when plugins are prepared and loaded one by one, as UCL didn't have visibility into plugins being prepared. But in the current Jenkins, classloaders for all the plugins are prepared, before any plugin gets started, so by the time Plugin.start() runs, UCL is fully functioning.
Therefore, there's no need to consult TCL for the purpose of resolving its own classes. I could have also removed the code that sets TCL, but because some libraries often depend on TCL and doesn't properly look at caller class, I'm leaving it in, even though it's generally a bad practice to rely on TCL in multi-classloader apps like Jenkins
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Merged revisions 32975,33588,33697,34342 via svnmerge from
https://www.dev.java.net/svn/hudson/branches/downgrade
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r32975 | kohsuke | 2010-07-16 21:27:59 +0200 (Fri, 16 Jul 2010) | 1 line
committed my partially modified version
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r33588 | dienomight | 2010-08-05 09:42:36 +0200 (Thu, 05 Aug 2010) | 13 lines
Added getBackupVersion (UpdateCenter)
downgrade button now shows version of backup war file
Added HudsonDowngradeJob (UpdateCenter)
downgrading process is works now as HudsonUpgradeJob
Changed rewriteHudsonWar (Lifecycle)
backup file is deleted when downgrading
hudson/model/Hudson/downgrade_success.jelly is no longer necessary
Changed rewriteHudsonWar(WindowsServiceLifecycle)
hudson run as windows service creates backup during upgrading
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r33697 | dienomight | 2010-08-11 17:09:48 +0200 (Wed, 11 Aug 2010) | 8 lines
committed changes:
"plugins downgrade functionality"
added:
* PluginDowngradeJob in UpdateCenter
* getCanDowngrade & getBackupPath & getBackupVersion in PluginWrapper
* additional "previous version" column in installed.jelly (PluginManager) with downgrade button (when it's possible to downgrade)
* doDowngrade in PluginManager
* deployBackup in UpdateSite
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r34342 | dienomight | 2010-09-03 09:52:13 +0200 (Fri, 03 Sep 2010) | 12 lines
Code improvements:
jelly files:
*I put text inside ${%} so it would be available for translation.
UpdateCenter:
*changed getCanDowngrade to isDowngradable
*getBackupVersion use JarFile class to get version of .war backup
PluginWrapper:
*changed getBackupPath to getBackupFile
*getBackupVersion use JarFile class to get version of plugin backup
PluginManager:
*changed condition in doDowngrade method
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git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@34543 71c3de6d-444a-0410-be80-ed276b4c234a
- click category heading on Available tab to show/hide plugins in that category
- add initial sort for plugins on Installed tab
- no mouseover bgcolor for Advanced tab
git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@31819 71c3de6d-444a-0410-be80-ed276b4c234a
Jesse Glick