PowerShell try/catch/finally

-ErrorAction Stop is changing things for you. Try adding this and see what you get:

Catch [System.Management.Automation.ActionPreferenceStopException] {"caught a StopExecution Exception" $error[0]}

That is very odd.

I went through ItemNotFoundException's base classes and tested the following multiple catches to see what would catch it:

try {  remove-item C:\nonexistent\file.txt -erroraction stop}catch [System.Management.Automation.ItemNotFoundException] {  write-host 'ItemNotFound'}catch [System.Management.Automation.SessionStateException] {  write-host 'SessionState'}catch [System.Management.Automation.RuntimeException] {  write-host 'RuntimeException'}catch [System.SystemException] {  write-host 'SystemException'}catch [System.Exception] {  write-host 'Exception'}catch {  write-host 'well, darn'}

As it turns out, the output was 'RuntimeException'. I also tried it with a different exception CommandNotFoundException:

try {  do-nonexistent-command}catch [System.Management.Automation.CommandNotFoundException] {  write-host 'CommandNotFoundException'}catch {  write-host 'well, darn'}

That output 'CommandNotFoundException' correctly.

I vaguely remember reading elsewhere (though I couldn't find it again) of problems with this. In such cases where exception filtering didn't work correctly, they would catch the closest Type they could and then use a switch. The following just catches Exception instead of RuntimeException, but is the switch equivalent of my first example that checks all base types of ItemNotFoundException:

try {  Remove-Item C:\nonexistent\file.txt -ErrorAction Stop}catch [System.Exception] {  switch($_.Exception.GetType().FullName) {    'System.Management.Automation.ItemNotFoundException' {      write-host 'ItemNotFound'    }    'System.Management.Automation.SessionStateException' {      write-host 'SessionState'    }    'System.Management.Automation.RuntimeException' {      write-host 'RuntimeException'    }    'System.SystemException' {      write-host 'SystemException'    }    'System.Exception' {      write-host 'Exception'    }    default {'well, darn'}  }}

This writes 'ItemNotFound', as it should.