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Null form fields causing flow to fail

I have a form with lots of sections and branching meaning not all of the form fields get filled usually. i have 15 date fields and similar number fields feeding a list box formatted the same. if i make all list fields text, the flow will run with null values present on the form. this is not ideal. how can i run my flow?


here is the error: 


OpenApiOperationParameterTypeConversionFailed. The 'inputs.parameters' of workflow operation 'Create_item' of type 'OpenApiConnection' is not valid. Error details: Input parameter 'item/Mileage10_Claim_Date' is required to be of type 'String/date'. The runtime value '""' to be converted doesn't have the expected format 'String/date'.



Hi there!  Do you have a Parse JSON step?  Is that where this is erroring out?  If so, this is caused by the "upload sample payload to build schema" bit that Flow/PA includes.  It's typically very helpful, but can cause problems for non-developers because it assigns a "type" to EVERY value.  So that means that future runs will need to have matching data, or you'll see this error.  (For me, it was an "Address 3" which is never filled out.


The "trick" is to remove the type for the offending field.  Check out John Liu's Thesis on the Parse JSON action for more details.  Specifically, "Problem 4".


Keep us posted.



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