Passing empty string '' to function sends '0'

Spoke too soon. Im trying something else.


PowerShell does love its coercion. So, know that your ValidatePattern isn’t helping; that forces the input into a string in order to do a regex match. [int] along makes sure you get an integer, and you can use a ValidateRange if you need to limit to, say, 100 to 999. Aside from that, in PowerShell’s mind, an empty string is the same as zero. I’m not sure there’s a declarative way to change it’s mind on that, unless I’m misunderstanding what you’re after.

I see. That makes sense. I just want to ensure that a terminating failure occurs if someone tries to pass an empty string ‘’ or " ", so after reading what you replied with I modified the function as such and all current functionality remained intact along with failing for passing in those empty values. :slight_smile:

I had to add the ValidateScript validation to catch passing in " ". The ValidateNotNullOrEmpty did not catch that but It did catch passing in ‘’ or “”.

function Add-Increment {
        [ValidateScript({ if([string]::IsNullOrWhiteSpace($_))
            throw "The argument is null or whitespace. Provide and argument that is not null or whitespace, and then try the command again"
        } })]


    Write-Verbose -Message ("Number {0} was passed into function" -f $Number)


    Write-Verbose -Message ("After increment, Number is: {0}" -f $Number)

    $CharCount = $(($Number | Measure-Object -Character).Characters)

    if($CharCount -gt 3)
        throw "Number suffix $Number surpassed 3 digits!"
        $Suffix = $Number.ToString("000")

    Write-Verbose -Message ("Suffix to be used: {0}" -f $Suffix)
    return $Suffix

Thanks, Don!