Understanding Disable-RunspaceDebug in PowerShell

Welcome back to Wahmans PowerShell Blog! Today we’re diving into a cmdlet that can be quite useful when working with PowerShell debugging, particularly in more complex scripting environments or multithreaded setups: Disable-RunspaceDebug.

Description: According to Microsoft, the Disable-RunspaceDebug cmdlet disables debugging on one or more runspaces, and releases any pending debugger stop.

This may sound advanced at first, but it’s actually quite useful once you work with scripts that initiate different threads or isolated runspaces. This cmdlet allows you to stop attaching the debugger to said runspaces, especially when you’re done debugging or want to resume execution without stepping through everything.

Let’s dive into 4 practical examples of using Disable-RunspaceDebug, from beginner to advanced:

Example 1: Basic Usage in the Default Runspace

# Enable first (for contrast)
Enable-RunspaceDebug

# ... do some debugging or hit a breakpoint ...

# Disable debugging
Disable-RunspaceDebug

In this example, we’re simply enabling and disabling the debugger in your current session. It’s especially helpful for beginner-friendly scripts where you’re just trying to catch and resolve small bugs.

Example 2: Conditional Debug Control

if ($debugMode) {
    Enable-RunspaceDebug
    Write-Host "Debugger enabled."
} else {
    Disable-RunspaceDebug
    Write-Host "Debugger disabled."
}

This shows how to toggle debugging in script execution based on a conditional flag. This can be useful during development, where you enable debugging mode without editing the core script each time.

Example 3: Debugging Multiple Runspaces

# Create a runspace pool
$runspacePool = [runspacefactory]::CreateRunspacePool(1,5)
$runspacePool.Open()

# Create a runspace and start a script block
$runspace = [powershell]::Create().AddScript({
    Write-Host "Running in separate runspace"
}).RunspacePool = $runspacePool

$handle = $runspace.BeginInvoke()

# Enable debugging on all runspaces
Enable-RunspaceDebug -Runspace $runspace.Runspace

# Later, disable debugging
Disable-RunspaceDebug -Runspace $runspace.Runspace

$runspace.EndInvoke($handle)

This example is a step up, as it demonstrates attaching and then detaching the debugger from a specific runspace. If you’re executing multiple tasks in parallel, this can be powerful.

Example 4: Disable All Active Debug Runspaces

# Find all current runspaces
$runspaces = [System.Management.Automation.Runspaces.Runspace]::DefaultRunspace

# This example assumes you've stored or discovered multiple runspaces with debugging enabled
# To disable all in one go:
Disable-RunspaceDebug -Runspace $runspaces

In this more advanced example, we assume you have a set of runspaces you’re managing, and you want to ensure all of them have debugging turned off, such as when cleaning up after a long debugging session across multiple threads or interactive tasks.

Conclusion

Disable-RunspaceDebug is your ally when you’re ready to exit PowerShell’s debugging mode, especially in multi-threaded or tool-heavy scripting environments. Whether you’re just toggling between debug states or managing multiple runspaces, it’s a tool worth knowing.

As always, Happy scripting, and I will see you in the next post!