Misleading ColdFusion QueryAddColumn Error Message

While generating a ColdFusion query using QueryNew, I added a new column using QueryAddColumn and encountered a misleading error message.

The value of parameter 3, which is currently varchar, must be a interface java.util.List value.

The last time I checked, varchar was considered a valid "java.util.list value"... so what's the problem? In Adobe ColdFusion 8 or 9, I believe that the array parameter was optional. (I could be wrong.) If you omit the 4th parameter, the error message indicates that there's a problem with parameter 3 instead of the missing 4th parameter. I tested the same code using Lucee 4.5/5 and the new column is added without any error. (I also tested Railo 4 & the error returned was "Can't cast String [varchar] to a value of type [Array]".)

While a wrong error message is not a show-stopping bug, it doesn't provide any helpful assistance to determine what the actual problem is. Thankfully the online documentation (https://cfdocs.org/queryaddcolumn) highlights the array parameter as "required" (even though it wasn't for Lucee.)

Test it here

https://www.trycf.com/gist/bc948b141eea337a1927a311e6b500e9

Source Code

	<!--- 20190103
	Tested using ColdFusion 2016,0,13,316217 & 2018,0,06,316308. Lucee 5.3.3.62 does not throw an error.
	GIST: https://gist.github.com/JamoCA/bc948b141eea337a1927a311e6b500e9
	BLOG: https://dev.to/gamesover/misleading-coldfusion-queryaddcolumn-error-message-1lih
	TRYCF: https://www.trycf.com/gist/bc948b141eea337a1927a311e6b500e9
	NOTE: Test code on CFFiddle.org to view actual error message. (TryCF displays sanitized error message.)
	--->
	<cfset myQuery = QueryNew("id", "int")>
	<cfset QueryAddColumn(myQuery, "Name", "varchar")>
	<!---
	To correct error, pass arrayNew(1) as the 4th parameter.
	NOTE: No rows exist in this sample, so only an empty array makes sense and probably shouldn't be required.
	The misleading error message is:
	"Parameter validation error for the QUERYADDCOLUMN function.
	The value of parameter 3, which is currently varchar, must be a interface java.util.List value."
	The error message should be indicateregarding the missing 4th required param:
	"The value of parameter 4 is missing, must be an array value."
	--->
	<cfdump var="#myQuery#">

view raw QueryAddColumn_error_message.cfm hosted with ❤ by GitHub

Follow-up

20190103: I've reported it to Adobe. It's bug #CF-4206471