Dude, where's my flow?

Got burned by FIM's wacky function behavior again, so I thought I'd actually create some documentation on it.

I set up a pretty common flow: Name = First Middle Last

However, when the middle name is empty, I don't want two blanks between first and last name.  So, how's this for a custom expression?  (Note that I'm assuming that first and last name are always present.)

Trim(givenName+" "+HR_MIDDLE_NAME)+" "+sn

Submit, import, sync.  Now I run a full sync from my target MA.  No errors.  We're good, right?  Not so fast; let's check the attribute flow.  No flow into Name.

Okay, so let's run a full sync preview on one of the connectors.  The status of the flow is Error.  (Good luck finding an error message.)

• Full sync preview
  • Connector updates
    • Export attribute flow
      • Outbound sync rules

Status	MV attribute	Mapping type	Data source attribute	Initial value	Final value
Error		sync-rule-mapping - expression	NAME		(Unchanged)

So what happened?  Evidently, FIM doesn't like it when you concatenate an attribute that isn't present on the metaverse object.  (Has a funny way of showing it though, doesn't it?)

For my reference and yours, here are the results of other experiments that I ran on this flow.

• HR_MIDDLE_NAME is not present in MV
• (Assume givenName and sn are always present)

Description	Function	Flow definition	Result/status
MV attribute not present, embedded expr in Trim	CustomExpression	Trim(givenName+" "+HR_MIDDLE_NAME)+" "+sn	Error
Same expression but using concat feature in portal interface	Concat	Trim(CustomExpression(givenName+" "+HR_MIDDLE_NAME))+" "+sn	Error
Added IsPresent check and removed Trim	CustomExpression	givenName+IIF(IsPresent(HR_MIDDLE_NAME)," "+HR_MIDDLE_NAME,"")+" "+sn	Success
Trim function with no assumptions	CustomExpression	Trim( ""+ IIF(IsPresent(givenName),givenName,"")+ " "+ IIF(IsPresent(HR_MIDDLE_NAME),HR_MIDDLE_NAME,"")+ " "+ IIF(IsPresent(sn),sn,"") )	Parse failure: Parameter of function Trim does not match
(Test embedded expr in Trim)	CustomExpression	Trim(givenName+" "+sn)	(Success)
(Test MV attribute not present in Trim)	CustomExpression	givenName+" "+HR_MIDDLE_NAME+" "+sn	(Error)