One of the challenges of writing error handling is determining whether the error is terminating or non-terminating.

A possible solution is to force all errors to be terminating by setting ErrorActionPreference to Stop.

Setting ErrorActionPreference to Stop is equivalent to adding -ErrorAction Stop to every command that supports it.

When exploring nesting try-catch-finally, the following snippet was used:

try {    
    Connect-Server 
    Get-ManagementObject | ForEach-Object { 
        try {     
            $_ | Set-ManagementObject -Property 'NewValue' 
        } catch { 
            Write-Error -ErrorRecord $_ 
        } finally { 
            $_ 
        }    
    }     
} catch { 
    throw
 } 

Setting ErrorActionPreference to Stop would remove the need to set an ErrorAction parameter on each of the commands (if those commands wrote non-terminating errors). However, doing so would also cause any informational errors written by Write-Error to completely stop the script.

For a script that implements a process, where the error handling can be strictly defined, the following workaround might be used. The ErrorAction for Write-Error is forcefully set to Continue, overriding the value held in the preference variable:

$ErrorActionPreference = 'Stop' 
try {    
    Connect-Server 
    Get-ManagementObject | ForEach-Object { 
        try {     
            $_ | Set-ManagementObject -Property 'NewValue' 
        } catch { 
            Write-Error -ErrorRecord $_ -ErrorAction Continue 
        } finally { 
            $_ 
        }    
    }     
} catch { 
    throw
 } 

Setting ErrorActionPreference to Stop is harder to apply when writing tools, for example, when writing the commands used by this script, doing so would remove the choice from the end user.

A need for complex error handling is often a sign that a script needs to be broken down into smaller units.