Issue Summary

Plugins with .obr extensions doesn't install when we use the workaround mentioned on Confluence 8.5 Upgrade Notes

Load custom plugins from your Confluence file system. Set the system atlassian.confluence.plugin.scan.directory to a target location of your custom plugins, which will be loaded into the system upon restart. We recommend a directory within the Confluence home directory, such as $CONFLUENCE_HOME/plugins/installed-plugins. Make sure you restart Confluence after setting this property.

This is reproducible on Data Center: Yes

Steps to Reproduce

Step-1. Set the system atlassian.confluence.plugin.scan.directory to a target location of your custom plugins.

CATALINA_OPTS="-Datlassian.confluence.plugin.scan.directory=/Users/sgupta20/confluence-home/atlassian-confluence-8.5.8/plugins/installed-plugins ${CATALINA_OPTS}"

Step-2. Place the plugins on the location set on above property.

-rw-r--r--@ 1 sgupta20  staff    327438 Jan 18  2023 confluence-source-editor-2.0.0.jar
-rw-r--r--@ 1 sgupta20  staff  52543251 May  8 08:22 linchpin-suite-5.9.0.obr

Step-3. Restart Confluence

Expected Results

The .obr plugins should be installed under Manage apps.

Actual Results

In the atlassian-confluence.log, we see the following error messages related to the failure.

ERROR [Catalina-utility-2] [atlassian.plugin.loaders.ScanningPluginLoader] deployPluginFromUnit Because of the following exception:
java.lang.IllegalArgumentException: The artifact URI file:/Users/sgupta20/confluence-home/atlassian-confluence-8.5.8/plugins/installed-plugins/linchpin-suite-5.9.0.obr is not a valid plugin artifact
	at com.atlassian.plugin.DefaultPluginArtifactFactory.create(DefaultPluginArtifactFactory.java:59)
	at com.atlassian.plugin.loaders.ScanningPluginLoader.deployPluginFromUnit(ScanningPluginLoader.java:141)
	at com.atlassian.plugin.loaders.ScanningPluginLoader.loadAllPlugins(ScanningPluginLoader.java:89)

Workaround

Re-enable the UI upload button and API
1. Set the system property upm.plugin.upload.enabled to true.
2. Perform a restart.
3. Upload the app through the UPM UI.
We recommend that you disable the button once your upload is complete, using the additional steps below.
4. Set the system property upm.plugin.upload.enabled to false,
5. Perform a restart.