Expression Error on User Interface - Length of input arrays must equal length of CDT/Dictionary array

Question

Expression evaluation error [evaluation ID = a667e:8b65e] in rule 'ntd_adminreportingdashboardmonthlycompliance' (called by rule 'ntd_adminreportingdashboard') at function a!forEach [line 42]: Error in a!forEach() expression during iteration 5: Expression evaluation error at function 'updatecdt' [line 44]: Length of input arrays must equal length of CDT/Dictionary array 
 Interface Code: 
 if(
 and(ri!isShowMonthlyCompliance = false,rule!GLB_isNotEmpty(ri!selectedMonthAndYear)),
 a!localVariables(
 local!searchVanpool,
 local!searchCoordinator,
 local!searchEmployer,
 local!searchOperationsContact,
 local!complianceData: a!refreshVariable(
 refreshOnVarChange: {
 ri!savedTripDataCounter,
 ri!selectedMonthAndYear
 },
 value: rule!INT_TRP_getTransitMonthlyComplianceStats(
 transitAgencyCode: index(ri!selectedMonthAndYear,"transitAgencyCode",{}),
 month: index(ri!selectedMonthAndYear, "month", {}),
 year: index(ri!selectedMonthAndYear, "year", {})
 )
 ),
 local!isComplainceDataPresent: and(
 local!complianceData.result.statusCode = 200,
 rule!GLB_isNotEmpty(index(local!complianceData.result.body,"vanpoolId",null))
 ),
 local!complianceDataReport: cast(
 typeof({'type!{urn:com:rideshare:trp}NTD_Admin_Reporting_Monthy_Complaince_Report'()}),
 local!complianceData.result.body
 ),
 if(
 local!complianceData.result.statusCode <> 200,
 a!boxLayout(
 label: "Monthly Compliance",
 contents: {
 rule!GLB_displayIntegerationErrorDetails(response: local!complianceData),
 a!paragraphField(value : local!complianceData)
 },
 style: "#f9cb9c"
 ),
 a!localVariables(
 local!viewVanpoolEmployerAndContacts: rule!NTD_getViewVanpoolEmployerAndContacts(
 vanpoolId: local!complianceDataReport.vanpoolId,
 pagingInfo: a!pagingInfo(1, - 1)
 ), 
 local!updatecomplianceDataReport: a!forEach(
 local!complianceDataReport,
 updatecdt(
 cdt: fv!item,
 fieldsAndValues: {
 employerName: index(
 index(
 local!viewVanpoolEmployerAndContacts,
 wherecontains(fv!item.vanpoolId,touniformstring(index(local!viewVanpoolEmployerAndContacts,"vanpool_id",""))),
 null
 ),
 "employer_name",
 ""
 ),
 employerCode: index(
 index(
 local!viewVanpoolEmployerAndContacts,
 wherecontains(fv!item.vanpoolId,touniformstring(index(local!viewVanpoolEmployerAndContacts,"vanpool_id",""))),
 null
 ),
 "employer_code",
 ""
 ),
 operationsContact: index(
 index(
 local!viewVanpoolEmployerAndContacts,
 wherecontains(fv!item.vanpoolId,touniformstring(index(local!viewVanpoolEmployerAndContacts,"vanpool_id",""))),
 null
 ),"operations_contact", "" ),
 coordinatorEmail: index(
 index(
 local!viewVanpoolEmployerAndContacts,
 wherecontains(fv!item.vanpoolId,
 touniformstring(index(local!viewVanpoolEmployerAndContacts,"vanpool_id",""))
 ),
 null
 ), "coordinator_email",""),
 coordinatorId: index(
 index(
 local!viewVanpoolEmployerAndContacts,
 wherecontains(fv!item.vanpoolId,
 touniformstring(index(local!viewVanpoolEmployerAndContacts,"vanpool_id",""))
 ),
 null
 ), "coordinator_id",""),
 
 }
 )
 ),
 local!operationsContactValues: union(
 local!updatecomplianceDataReport.operationsContact,
 local!updatecomplianceDataReport.operationsContact
 ),
 local!employerNameValues: union(
 local!updatecomplianceDataReport.employerName,
 local!updatecomplianceDataReport.employerName
 ),
 local!filteredReportVanpool: if(
 rule!APN_isBlank(local!searchVanpool),
 local!updatecomplianceDataReport,
 index(
 local!updatecomplianceDataReport,
 wherecontains(
 local!searchVanpool,
 touniformstring(
 local!updatecomplianceDataReport.vanpoolId
 )
 ),
 {}
 )
 ),
 local!filteredReportOpsContact: if(
 rule!APN_isBlank(local!searchOperationsContact),
 local!filteredReportVanpool,
 index(
 local!filteredReportVanpool,
 wherecontains(
 local!searchOperationsContact,
 touniformstring(
 local!filteredReportVanpool.operationsContact
 )
 ),
 {}
 )
 ),
 local!filteredReportCoord: if(
 rule!APN_isBlank(local!searchCoordinator),
 local!filteredReportOpsContact,
 index(
 local!filteredReportOpsContact,
 wherecontains(local!searchCoordinator,touniformstring(local!filteredReportOpsContact.coordinatorName)),
 {}
 )
 ),
 local!filteredReportEmployer: if(
 rule!APN_isBlank(local!searchEmployer),
 local!filteredReportCoord,
 index(
 local!filteredReportCoord,
 wherecontains(local!searchEmployer,touniformstring(local!filteredReportCoord.employerName)),
 {}
 )
 ),
 local!exportUri: getdatasubsetdownloadlinkfromprocess(
 processModelUuid: cons!NTD_EXPORT_ADMIN_REPORTING_MONTHLY_COMPLIANCE_REPORT_PROCESS_MODEL,
 input: a!toJson(
 {
 a!map(
 transitAgencyCode: ri!selectedMonthAndYear.transitAgencyCode, 
 month: ri!selectedMonthAndYear.month, 
 year: ri!selectedMonthAndYear.year, 
 coordinator :local!searchCoordinator, 
 employer :local!searchEmployer , 
 operationsContact:local!searchOperationsContact , 
 vanpool:local!searchVanpool
 )
 }
 )
 ),
 a!boxLayout(
 label: "Monthly Compliance",
 contents: {
 a!boxLayout(
 label: "Filters",
 contents: {
 a!columnsLayout(
 columns: {
 a!columnLayout(
 contents: {
 a!dropdownField(
 label: "Vanpool ID",
 placeholder: cons!GLB_DROPDOWN_PLACEHOLDER_LABEL,
 choiceLabels: local!complianceDataReport.vanpoolId,
 choiceValues: local!complianceDataReport.vanpoolId,
 value: local!searchVanpool,
 saveInto: local!searchVanpool,
 searchDisplay: "ON"
 )
 }
 ),
 a!columnLayout(
 contents: {
 a!dropdownField(
 label: "Coordinator Name",
 placeholder: cons!GLB_DROPDOWN_PLACEHOLDER_LABEL,
 choiceLabels: union(local!updatecomplianceDataReport.coordinatorName, 
 local!updatecomplianceDataReport.coordinatorName),
 choiceValues: union(local!updatecomplianceDataReport.coordinatorName, 
 local!updatecomplianceDataReport.coordinatorName),
 value: local!searchCoordinator,
 saveInto: local!searchCoordinator,
 searchDisplay: "ON"
 )
 }
 ),
 a!columnLayout(
 contents: {
 a!dropdownField(
 label: "Employer Name",
 placeholder: cons!GLB_DROPDOWN_PLACEHOLDER_LABEL,
 choiceLabels: local!employerNameValues,
 choiceValues: local!employerNameValues,
 value: local!searchEmployer,
 saveInto: local!searchEmployer,
 searchDisplay: "ON"
 )
 
 }
 ),
 a!columnLayout(
 contents: {
 a!dropdownField(
 label: "Operations Contact",
 placeholder: cons!GLB_DROPDOWN_PLACEHOLDER_LABEL,
 choiceLabels: local!operationsContactValues,
 choiceValues: local!operationsContactValues,
 value: local!searchOperationsContact,
 saveInto: local!searchOperationsContact,
 searchDisplay: "ON"
 )
 }
 ),
 a!columnLayout(contents: {})
 }
 )
 },
 isCollapsible: true(),
 isInitiallyCollapsed: true()
 ),
 a!gridField(
 label: "",
 labelPosition: "ABOVE",
 emptyGridMessage: "There are no vanpools for the selected month and year.",
 data: local!filteredReportEmployer,
 columns: {
 a!gridColumn(
 label: "Vanpool ID",
 sortfield: "vanpoolId",
 value: fv!row.vanpoolId
 ),
 a!gridColumn(
 label: "Coordinator",
 sortField: "coordinatorName",
 value: fv!row.coordinatorName
 ),
 a!gridColumn(
 label: "Employer",
 sortField: "employerName",
 value: fv!row.employerName
 ),
 a!gridColumn(
 label: "Operations Contact",
 sortField: "operationsContact",
 value: fv!row.operationsContact
 ),
 a!gridColumn(
 label: "Occupancy %",
 sortField: "occupancy",
 value: fv!row.occupancy
 ),
 a!gridColumn(
 label: "Capacity",
 sortField: "capacity",
 value: fv!row.capacity
 ),
 a!gridColumn(
 label: "UPT",
 sortField: "upt",
 value: rule!GLB_formatNumberWithCommasAtThousands(fv!row.upt)
 ),
 a!gridColumn(
 label: "VRM",
 sortField: "vrm",
 value: rule!GLB_formatNumberWithCommasAtThousands(fv!row.vrm)
 ),
 a!gridColumn(
 label: "VRH",
 sortField: "vrh",
 value: fv!row.vrh
 ),
 a!gridColumn(
 label: "PMT",
 sortField: "pmt",
 value: rule!GLB_formatNumberWithCommasAtThousands(fv!row.pmt)
 ),
 a!gridColumn(
 label: "Days Run",
 sortField: "daysOperated",
 value: fv!row.daysOperated
 ),
 a!gridColumn(
 label: "Days Planned",
 sortField: "scheduledDays",
 value: fv!row.scheduledDays
 ),
 a!gridColumn(
 label: "Report Completion %",
 sortField: "reportingCompletion",
 value: fv!row.reportingCompletion
 ),
 a!gridColumn(
 label: "Fuel Gallons",
 sortField: "fuelGallons",
 value: fv!row.fuelGallons
 ),
 a!gridColumn(
 label: "Fuel Cost",
 sortField: "fuelCost",
 value: rule!APN_dollar(fv!row.fuelCost, true)
 ),
 a!gridColumn(
 label: "Exceptions",
 sortField: "exceptions",
 value: fv!row.exceptions
 )
 },
 initialSorts: {
 a!sortInfo(field: "vanpool_id", ascending: false)
 },
 selectable: true,
 selectionStyle: "ROW_HIGHLIGHT",
 selectionValue: if(
 rule!APN_isEmpty(ri!selectedVanpool),
 null,
 wherecontains(
 ri!selectedVanpool.vanpoolId,
 a!flatten(
 index(
 local!complianceData.result.body,
 "vanpoolId",
 null
 )
 )
 )
 ),
 selectionSaveInto: {
 a!save(ri!selectedVanpool, null),
 a!save(ri!selectedVanpool, fv!selectedRows),
 if(
 rule!GLB_isNotEmpty(ri!selectedVanpool),
 a!save(ri!isShowVanpoolHistoricalStats, false),
 {}
 ),
 a!save(ri!isShowMonthlyCompliance, false)
 },
 spacing: "DENSE"
 ),
 a!linkField(
 labelPosition: "COLLAPSED",
 links: {
 a!safeLink(
 label: "Click Here to Export This Report",
 uri: local!exportUri
 )
 },
 showWhen: or(
 rule!APN_isEmpty(local!exportUri),
 local!isComplainceDataPresent
 )
 )
 },
 showWhen: and(
 ri!isShowMonthlyCompliance = false,
 rule!GLB_isNotEmpty(ri!selectedMonthAndYear),
 rule!GLB_isNotEmpty(local!complianceData)
 ),
 style: "#f9cb9c",
 isCollapsible: true,
 marginBelow: "STANDARD"
 )
 )
 )
 ),
 {}
)

Mike Schmitt · Answer

My first instinct would be to advise you to simplify, as possible, your repeated and complex/nested index() calls, particularly since you're mixing index and property functionality all under the index() function. For instance: How many times do you need to re-run the same "whereContains()" call finding the position of the current vanpool ID in the employer/contacts list? This could easily be an in-loop (per-iteration) local variable. 
 Per the actual error message - it seems that one or more of these nested calls is returning an array of potentially greater length than 1; but in either case I should note that the result of your nested index() calls will be a list type, inherited up from your whereContains() calls, which will each return a list of indices (even when only one is found). I'm guessing this is likely throwing off the updateCdt() results, as it's fairly finnicky about such things.