continue keyword causes System Error

[danielniccoli]

Describe the bug

The following code throws an error Get-MgGroupMember_List: System error. due to the continue keyword in the ForEach-Object:

$members = Get-MgGroupMember -GroupId $groupId -All | ForEach-Object {
    # Skip some users
    if($_.Id -eq "7ac26e6b-0fc8-47b2-9e96-20326525db9c") {
        continue
    }

    $_ 
}

I am aware that I can work around the bug by putting my logic inside the if-statement.

Expected behavior

The use of the continue keyword should not cause an exception, as shown below:

@(1,2,3) | % {
    if($_ -eq 2) { continue }
    $_
}

How to reproduce

See above

SDK Version

No response

Latest version known to work for scenario above?

No response

Known Workarounds

No response

Debug output

Click to expand log

```

</details>


### Configuration

_No response_

### Other information

_No response_

[timayabi2020]

Hi @danielniccoli this seems to be an issue with PowerShell as an environment and the way it handles the continue statement in a loop. From the documentation here, continue only works with traditional looping constructs such as for, foreach, while and do-while. PowerShell's ForEach-Object executes in a pipeline, and continue is not valid within pipeline execution.

If you try out this script, you'll notice that continue is silently ignored. This is because the array of objects is not a streaming cmdlet.

$stuff = @()
$person1 = New-Object PSObject -Property @{FirstName = "John"}
$person2 = New-Object PSObject -Property @{FirstName = "Doe"}
$stuff+=$person1
$stuff+=$person2
$res = $stuff | ForEach-Object {
	if($_.FirstName -eq 'John') {
		continue
	}
	$_
}

Meanwhile Get-MgGroupMember executes in a streaming pipeline and instead of ignoring continue, PowerShell raises a ContinueException hence the reason for that error

[secretworkpersona]

Hi @timayabi2020. So I'm clear, when you say silently ignored do you mean continue executes with no error or warning? When I run your script there is no output because continue exits the loop before $_ on the first pass because FirstName equals John. Thx.

[timayabi2020]

@secretworkpersona sorry I shouldn't have said Silently ignored instead I should have said Silently exists the loop as opposed to throwing an error.

[danielniccoli]

Hi @danielniccoli this seems to be an issue with PowerShell as an environment and the way it handles the continue statement in a loop. From the documentation here, continue only works with traditional looping constructs such as for, foreach, while and do-while. PowerShell's ForEach-Object executes in a pipeline, and continue is not valid within pipeline execution.

If you try out this script, you'll notice that continue is silently ignored. This is because the array of objects is not a streaming cmdlet.

$stuff = @()
$person1 = New-Object PSObject -Property @{FirstName = "John"}
$person2 = New-Object PSObject -Property @{FirstName = "Doe"}
$stuff+=$person1
$stuff+=$person2
$res = $stuff | ForEach-Object {
	if($_.FirstName -eq 'John') {
		continue
	}
	$_
}

Meanwhile Get-MgGroupMember executes in a streaming pipeline and instead of ignoring continue, PowerShell raises a ContinueException hence the reason for that error

Thanks, I was missing that part from the documentation:

Using continue inside a pipeline, such as a ForEach-Object script block, not only exits the pipeline, it potentially terminates the entire runspace.