Expression error

Question

Expression evaluation error at function a!isNullOrEmpty parameter 1 ???null???: Invalid index: Cannot index property 'x' of type Text into type List of Variant. 
 
 This error is faced by user when opening record action. This is only faced by a specific user. when I open the same request, I am not getting this error. Also in design error log only highlights the process which calls the interface. This error looks very high level and not highlighting the object name clearly. Does anyone faced any similar kind of issue? Please let me know if there is way to debug this.

VarunTejaGurrapu · Answer

Hi Radhamani Ramasamy , I hope you are indexing using the following expression: a!isNullOrEmpty(ri!data.x). 
 But at runtime: 
 
 ri!data NOT a map/CDT, It is a List of Variant (array) 
 
 So Appian can&rsquo;t do .x(Index) on a list 
 Correction : Always use Index() Function. a!isNullOrEmpty(index(ri!data, "x", null)) 
 Note : Never use dot notation ( .x ) unless you are 100% sure it's a single object. If you cannot find the object that poses this error, you can search it in the objects tab and put search type as expression, and check in the dependent objects only. Quick summary : The error happens because your code assumes a single object but receives a list for that specific user, causing .x access to fail. Fix it by using safe access like index() instead of dot notation, since data structure can vary per user.

Shubham Aware · Answer

Generally it happens when, The specific user has corrupt or unexpected data in their record.
Open Process Monitor -> find that user's process instance -> inspect the variable values directly.
Replace unsafe dot notation like pv.myData.x with index(pv.myData, "x", null) before a!isNullOrEmpty() in the record action interface/process.

Try this things and let us know if that works for you.