PowerShell: break nested loops

Question

There should be a break command in PowerShell that can exit nested loops by assigning a label. Just it doesn't work. Here's my code:

$timestampServers = @(
    "http://timestamp.verisign.com/scripts/timstamp.dll",
    "http://timestamp.comodoca.com/authenticode",
    "http://timestamp.globalsign.com/scripts/timstamp.dll",
    "http://www.startssl.com/timestamp"
)

:outer for ($retry = 2; $retry -gt 0; $retry--)
{
    Write-Host retry $retry
    foreach ($timestampServer in $timestampServers)
    {
        Write-Host timestampServer $timestampServer
        & $signtoolBin sign /f $keyFile /p "$password" /t $timestampServer $file
        if ($?)
        {
            Write-Host OK
            break :outer
        }
    }
}
if ($retry -eq 0)
{
    WaitError "Digitally signing failed"
    exit 1
}

It prints the following:

retry 2
timestampServer http://timestamp.verisign.com/scripts/timstamp.dll
Done Adding Additional Store
Successfully signed and timestamped: C:\myfile.dll
OK
retry 1
timestampServer http://timestamp.verisign.com/scripts/timstamp.dll
Done Adding Additional Store
Successfully signed and timestamped: C:\myfile.dll
OK

ERROR: Digitally signing failed

What have I done wrong?

Can I have goto and labels, please?

Using Windows 7 and I guess PS 2.0. This script is supposed to run on PS 2 at least.

score 36 · Accepted Answer · 2014-06-04 18:12:13Z

36

You do not add the colon when using break with a loop label. This line:

break :outer

should be written like this:

break outer

For a further demonstration, consider this simple script:

:loop while ($true)
{
    while ($true)
    {
        break :loop
    }
}

When executed, it will run forever without breaking. This script however:

:loop while ($true)
{
    while ($true)
    {
        break loop
    }
}

exits as it should because I changed break :loop to break loop.

edited Jun 4, 2014 at 18:12

answered Jun 4, 2014 at 18:06

user2555451

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7 Comments

Nate Hekman Over a year ago

Technet docs at technet.microsoft.com/en-us/library/hh847873.aspx show the colon in the break statement, but I tested this as well and found the same as iCodez: with the colon it ignored the label (just broke from the inner loop), without the colon it would break from the labeled loop.

Adil Hindistan Over a year ago

@iCodez no, actually you are right... I thought it was working but it is not.

ygoe Over a year ago

Thank you. I must have overlooked that. You should never rely on arbitrary websites to learn a programming language. But with PowerShell this seems necessary.

papo Over a year ago

the Doc must have been fixed, there is no colon there now. Nor when I change Doc version to PS 3, or use Get-Help about_break in PS 5.1 console. But it still is on Hey, Scripting Guy! Blog

Andy McRae Over a year ago

thanks for the demonstration. It worked fine for me

|

Adil Hindistan · Accepted Answer · 2014-06-04 18:20:38Z

So, I changed the code a bit to make it clear

$timestampServers = @(
    "http://timestamp.verisign.com/scripts/timstamp.dll",
    "http://timestamp.comodoca.com/authenticode",
    "http://timestamp.globalsign.com/scripts/timstamp.dll",
    "http://www.startssl.com/timestamp"
)


:outer for ($retry = 2; $retry -gt 0; $retry--)
{
    Write-Host retry $retry
    foreach ($timestampServer in $timestampServers)
    {
        Write-Host timestampServer $timestampServer
        #& $signtoolBin sign /f $keyFile /p "$password" /t $timestampServer $file

        if ($true)
        {

            break :outer
            Write-Host OK
        }
    }
}
if ($retry -eq 0)
{
    Write-Error "Digitally signing failed"  ## you have a typo there
    exit 1
}

This produces the following:

retry 2
timestampServer http://timestamp.verisign.com/scripts/timstamp.dll
retry 1
timestampServer http://timestamp.verisign.com/scripts/timstamp.dll
C:\temp\t.ps1 : Digitally signing failed
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,t.ps1

So, skips Write-Host OK, but also seems to continue to loop. In other words, it acts like 'Continue' statement.

Changed it like the folks mentioned to remove ':', although PowerShell documentation does not exclude it:

 if ($true)
        {

            break outer
            Write-Host OK
        }

I get the correct behavior.

retry 2
timestampServer http://timestamp.verisign.com/scripts/timstamp.dll

Long story short... do not use ':'

No, I have a function there, WaitError. This code was from a much greater script.

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