QvdNoOfRecords Script File function behaviour change between QlikView 11.20 and 12.10

After performing an upgrade from 11.20 SR16 to 12.10 SR6 a behaviour change with the script file function QvdNoOfRecords was discovered. This script function normally returns the number of records in a specified QVD or returns a NULL if no QVD can be found. This is very useful as you can create elements in the load script that load data if it exists or moves on e.g.

IF Alt(QvdNoOfRecords('D:\QV Data\UPGRADE\S2_WIDGET_Billing_S2017.qvd'),0) > 0 THEN ... ELSE ... END IF

In release 12.10 SR6 the function throws a Script error.
 

Currently there is no clear understanding why this script function is returning a script error and not a NULL as it was before. The main culprit seems to be the fact that some QVDs might have been created in an older version of QlikView.

Bug QV-12407 has been created for R&D to clarify if this is an intended change or a bug. If the change is as designed, then a documentation improvement will be requested to explicitly explain how function QvdNoOfRecords() handles non-existent files in the help site.

Currently there is no clear understanding why this script function is returning an error and not a NULL as it was before. As a workaround the following script can be added to the loading script:

IF (NOT isNull(qvdCreateTime('C:\temp\QV Data\UPGRADE\DeloitteSlownessDuringReload_FACT_EVALUATION.qvd'))) THEN
LET vRecords = Alt(QvdNoOfRecords('C:\temp\QV Data\UPGRADE\DeloitteSlownessDuringReload_FACT_EVALUATION.qvd'),0);
END IF
TRACE Records: $(vRecords);

Another workaround is to try to load the QVD independently in QlikView 12.10 SR6 and then storing it out again.