Workflow history error – Stopped (error): Could not find user

If you have ever coded with the WorkflowParticipant provider class you may have come across the following stop error in workflow history “Stopped (error): Could not find user”. After spending a couple of hours tracing through code I eventually located the cause of the error.

In my case the participant provider class is supposed to retrieve an employeeId from a form and translate it to a userID which it  then returns in the WorkflowUserList. However in my case no user relation had been setup between the employee and the user thus the class ended up adding an empty user to the list causing the SysWorkflowProviderService::resolveDueDateAsUser  method to fail as there it couldnt find the blank user. Thus:

Resolution:
1. Always check the user id’s that you are adding to WorkflowUserList that your provider returns, to ensure that they are not empty.

E.G: Wrong:

userList.add(SysCompanyUserInfo::emplId2UserId(resp);

Right:

respUser = SysCompanyUserInfo::emplId2UserId(resp); 
if (respUser == '') { 
    throw error(strfmt("No user relationship defined for employee %1",resp)); 
} 
userList.add(respUser);