DRAFT KB-XXXX Quick app "Trends" tab fails to load when user field added due to invalid value for "links"

Symptoms

After creating a quick app (New Application --> Create Using Application Builder (Full)) and specifying a user field for the form, the below error is encountered when trying to land on the created "Trends" page after submitting a data entry through the quick app:

"Expression evaluation error at function a!gridField [line XXX]: A grid component [label=“null”] has an invalid value for “columns”. A grid column [label=“<USER_FIELD>”] has encountered an error. Expression evaluation error at function a!linkField [line XXX]: An AnyLinkField component [label=“”] has an invalid value for “links”. The array of links cannot have null items."

Cause

This issue has been reported to the Appian Product Team. The reference number for this issue is AN-140630.

Workaround

Navigate to the interface for the "Trends" tab *_All<Record_Singular>: to find the interface, open the site object for the quick app, click the "<Record_Singular>" link within the Content column under the Pages section, and then open the Interface object.
The format username expression rule!IST_FormatName(fv!row.<USER_FIELD>() is wrapping the username parameter of the expression rule!IST_UserRecordLink() rather than the label parameter. The below code will remediate the issue, as well as perform a null check in case the user field is not set to required:

a!gridColumn(
label: "<User_Field>",
sortField: "<userfield>",
value: a!linkField(
links: {if(isnull(fv!row.<userfield>),{},
rule!XXXXX_UserRecordLink(
fv!row.<userfield>,
XXXXX_FormatName(fv!row.<userfield>)
)
)
}
)
)

Affected Versions

This article applies to Appian 19.2 and Appian 19.3:

Last Reviewed: September 2019