Where is this apparent documentation error best reported?

The Short URLs section of the Installation via Deb Apps page either has an error or I’m not reading it right:

The instructions say to change Context path="/xwiki" tp Context path="/" in /etc/xwiki/xwiki-tomcat9.xml. After doing so this error occurs:

13-Jul-2021 19:51:27.230 WARNING [main] org.apache.catalina.core.StandardContext.setPath A context path must either be an empty string or start with a ‘/’ and do not end with a ‘/’. The path [/] does not meet these criteria and has been changed to []
13-Jul-2021 19:51:27.231 WARNING [main] org.apache.catalina.startup.HostConfig.deployDescriptor The path attribute with value [] in deployment descriptor [/etc/tomcat9/Catalina/localhost/ROOT.xml] has been ignored
13-Jul-2021 19:51:27.237 WARNING [main] org.apache.catalina.startup.HostConfig.deployDescriptor Deployment of deployment descriptor [/etc/tomcat9/Catalina/localhost/ROOT.xml] with an external docBase means the directory [/var/lib/tomcat9/webapps/ROOT] in the appBase will be ignored

At which point:

HTTP Status 500 – Internal Server Error

Type Exception Report

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

java.lang.NullPointerException com.xpn.xwiki.web.Utils.getContextComponentManager(Utils.java:690) com.xpn.xwiki.web.Utils.getComponent(Utils.java:747) com.xpn.xwiki.web.Utils.getComponent(Utils.java:776) com.xpn.xwiki.web.Utils.getComponent(Utils.java:729) org.xwiki.wysiwyg.filter.ConversionFilter.doFilter(ConversionFilter.java:55) org.xwiki.container.servlet.filters.internal.SetHTTPHeaderFilter.doFilter(SetHTTPHeaderFilter.java:63) org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208) org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111) org.xwiki.resource.servlet.RoutingFilter.doFilter(RoutingFilter.java:132)

Note The full stack trace of the root cause is available in the server logs.

Apache Tomcat/9.0.31 (Ubuntu)

Instead of reporting doc errors, it’s best to fix the doc directly at Installation using Debian (.DEB) packages (XWiki.org) (it’s a wiki after all! ;)).

Now could you explain what value you’ve used to fix the problem? In your message you only mention that Context path="/" is an issue for Tomcat 9 but you don’t mention the right context value to use for the ROOT context. Empty string? (if I read Apache Tomcat 9 Configuration Reference (9.0.50) - The Context Container correctly it’s the empty string).

Since I did not succeed in getting short URLs to work, it was not appropriate to update the wiki, as I don’t have a correction available. Would it be appropriate to put a note there saying “This is wrong. Can someone who knows the right way please update this page”?

This is not fully about short URLs. All we discussed here is how to deploy XWiki under the ROOT servlet context. This shouldn’t be a problem and it should be very easy (it’s not even related to XWiki). Did you try with an empty context path as indicated in the tomcat doc? What happens? Can you show your context.xml file?

See also java - Deploying my application at the root in Tomcat - Stack Overflow

It will start with either Context path="" or Context path=/xwiki. I had simply reverted to the latter before. Should the former suffice to satisfy the goal of the document?