ValidatePatternAttribute accepting invalid input

Question

I have a powershell script in a file "Publish-MyProj.ps1" with a header defined like this:

[CmdletBinding()]
Param(
    [Parameter(Mandatory=$True)]
    [ValidatePattern("\d{1,2}\.\d{1,2}\.\d{1,3}")]
    [string]$Version
)

When I run the script like this:

.\Publish-MyProj.ps1 10.2

It shows an error, which is an expected behaviour.

However, when I run it with an almost alright version:

.\Publish-MyProj.ps1 111.2.25

It does not fail, even though the first number exceeds the number of allowed digits.

Is it a bug or am I doing it wrong?

beatcracker · Accepted Answer · 2015-10-09 13:54:33Z

2

It's because you've not specified your regex to match from beginning of the string, so it matches 111.2.25 and doesn't fail.

Use this regex (note ^ modifer): ^\d{1,2}\.\d{1,2}\.\d{1,3}

Or even better: ^\d{1,2}\.\d{1,2}\.\d{1,3}$

P.S. You can easily test your regex at https://regex101.com and see what matches and not.

answered Oct 9, 2015 at 13:54

beatcracker

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2 Comments

I am trying to learn powershell, so I have completely missed this rookie mistake while my mind was elsewhere.

@Santhos I think we all had those moments :).