PowerShell 3 bug with stack trace by Michael Naumov

Active

Type:	Bug
ID:	773611
Opened:	12/5/2012 5:48:57 PM
Access Restriction:	Public

Workaround(s)

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User(s) can reproduce this bug

If we run the following script in PowerShell 3, we will see a wrong stacktrace

===
[CmdletBinding()]
param
(
)

$script:ErrorActionPreference = "Stop"

$null.ToString()
===

Details (expand)

Always Happens

No, this is new to the most recent version

Let’s create the following Script.ps1 script

===
[CmdletBinding()]
param
(
)

$script:ErrorActionPreference = "Stop"

$null.ToString()
===

if we run it in PowerShell 3 we will see

===
C:\Scripts\Script.ps1 : You cannot call a method on a null-valued expression.
At line:1 char:1
+ C:\Scripts\Script.ps1
+ ~~~~~~~~~~~~~~~
    + CategoryInfo         : InvalidOperation: (:) [Script.ps1], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull,Script.ps1
===

As you see stacktrace here shown as At line:1 char:1.

If we run the same script from PowerShell 2

===
ToString : You cannot call a method on a null-valued expression.
At C:\Scripts\Script.ps1:8 char:15
+ $null.ToString <<<< ()
    + CategoryInfo         : InvalidOperation: (ToString:String) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : InvokeMethodOnNull
===

which is much better, it shows real stacktrace

I found that if we comment line #1 or #6, PowerShell 3 shows stacktrace a bit better

===
ToString : You cannot call a method on a null-valued expression.
At C:\Scripts\Script.ps1:8 char:1
+ $null.ToString <<<< ()
    + CategoryInfo         : InvalidOperation: (ToString:String) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : InvokeMethodOnNull
it shows correct line but still incorrect column. And I could not find a way to show column properly.
===

But I found a workaround how to show line properly and keep lines #1 and #6 unchanged.

You just need to insert Trap statement it will now work

===
[CmdletBinding()]
param
(
)

$script:ErrorActionPreference = "Stop"
Trap { throw $_ }
$null.ToString()
===

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Posted by Michael Naumov on 12/6/2012 at 1:16 AM

The following line is a workaround which works in both PowerShell 2 & 3

Trap { throw $_ }

Insert it in the top of your script

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