UserList macro fires a NullPointerException due to conflict on WikiDescriptorManager field

[slauriere]

Steps to reproduce

In a wiki page, insert the userList macro as follows:

{{userList properties="avatar,username,email,company,phone" users="XWiki.JohnDoe,XWiki.MaryJohn" fixedTableLayout="true"/}}

Expected result

The macro displays a table with the list of passed users.

Actual result

Exception:

java.lang.NullPointerException
 at com.xwiki.macros.AbstractProMacro.execute(AbstractProMacro.java:113)
 at org.xwiki.rendering.internal.transformation.macro.MacroTransformation.transform(MacroTransformation.java:309)
 at org.xwiki.rendering.internal.transformation.DefaultRenderingContext.transformInContext(DefaultRenderingContext.java:183)

See full stack trace:
exception.txt

[slauriere]

As pointed out by @michitux, the issue is due to a conflict between AbstractProMacro and UserListMacro declaring both a field named wikiDescriptorManager. I'm adding a reference to a discusion on the #product chat on how to solve the issue (date: August 30 2023, 4:30pm) cc @snazare

[slauriere]

Adding excerpts from the discussion on the #product chat:

• It is due to AbstractProMacro and UserListMacro declaring a field named wikiDescriptorManager which confuses the ComponentManager (as confirmed by Thomas, this is not supported)
• Anca points out that there is way too much private stuffs without getters in the abstract pro macro class for an abstract class
• I asked whether we should rename the field in the inherited class to something different. Thomas replied it could be exposed as a protected field instead, and that it all depends if we want to expose that field as an API or not.
• Anca points out that the fix would be to either make getters to those fields or to make it a protected field, or, if you don't want it to be API, look it up dynamically in the abstract pro macro function that needs it and use it then (scope it to the function that absolutely needs it, as a need of the function and not as a need of the class and superclasses)

[slauriere]

I introduced a getter for field wikiDescriptorManager in AbstractProMacro and updated UserListMacro to use that getter instead of declaring the same field locally. This updated version works successfully on my side with XWiki 15.6 (while I was able to reproduce the NullPointerException beforehand).

ccing @raphj since it seems the issue was introduced in c845afc

[raphj]

Thanks for the heads up and the fix @slauriere!

[slauriere]

Also ccing @snazare just in case :-)

[snazare]

thank you very much! We will plan a release soon :)