-Verbose dangerous?

PowerShell Help
1

Hi, when I add -Verbose to a command it changes the termination behavior.

when adding -verbose when $ErrorActionPreference = “Stop”, the command continues instead of stopping.

 $ErrorActionPreference = "Stop"
 New-Item existingItem.txt  -Verbose

I believe this should stop, not continue. Why am I mistaken?

$ErrorActionPreference = "Stop"
$VerbosePreference = "continue"

#creating a file for first run only
if(-Not (Test-Path test.txt))
{
    new-item test.txt  -Verbose 
}

#create the same file
new-item test.txt  -Verbose
Write-output 'This will never output because of the error above... or will it'


new-item test.txt 
Write-output 'This will ALSO never output because of the error above'
2

please see get-help about_Preference_Variables and\or https://technet.microsoft.com/en-us/library/hh847796.aspx

The default value of the VerbosePreference variable is SilentlyContinue. This will be used in place of the ErrorActionPreference variable when the -verbose switch is used, unless you specify the ErrorAction on the command.

This will work the way you think it should

$ErrorActionPreference = "Stop"
$VerbosePreference = "continue"

#creating a file for first run only
if(-Not (Test-Path test.txt))
{
    new-item test.txt  -Verbose 
}

#create the same file
new-item test.txt  -Verbose -ErrorAction Stop
Write-output 'This will never output because of the error above... or will it'


new-item test.txt 
Write-output 'This will ALSO never output because of the error above'
3

Thanks Jonothan, but I’m not seeing any documentation that -Verbose overrides $ErrorActionPreference

I’ve also looked in about_Common_Parameters
https://technet.microsoft.com/en-us/library/hh847884.aspx

But i can’t find anything that states the -Verbose will override $ErrorActionPreference

I would have guessed that -Verbose would only effect the the Verbose pipeline, but it looks to change the ErrorPipeline as well!

4

It depends on how the command is coded internally. When -Verbose is enabled, it’s possible that the command - internally - isn’t following a code path that can throw an exception. That’s not a good command design, and it isn’t a universal shell behavior. If you’ve verified the behavior, I’d suggest opening a ticket on UserVoice for the PowerShell team. Or, since New-Item is part of PowerShell Core, you might review the code on the PowerShell Core GitHub, and see if you can find the problem and propose a fix.