COM objects and PowerShell process exit



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COM objects and PowerShell process exit

Postby ZGF2aWQuamFkZQ » Sun, 05 Nov 2006 07:59:02 GMT

I've got a simple script file that creates an in-process COM object. I'm 
seeing some very strange behavior when PowerShell has a normal exit and the 
COM object is being released during clean up. What I'm seeing is that during 
the Release call within the COM object, the thread just vanishes and the 
PowerShell process exits with a normal return code. 

The COM object in question is mine so I've been debugging this and I can see 
that the thread that is making the COM call just vanishes right in the middle 
of fairly simplistic code. The point that this happens is never that same 
place within the object's Release() method code, it's always a random 
location and is often right in the middle simple C code. To help debug this 
issue, which seems like a timing issue to me, I put a simple for loop in the 
object's Release() method that does simple things (i.e. int_i = int_i + 5). 
Invariably the thread just vanishes while single stepping through this code.

While watching the other threads in the process I can tell that they are in 
the GC and are doing things like: GCHeap::FinalizerThreadWatchDogHelper right 
before the thread executing my code vanishes. 

My question is, is there something in PowerShell or the CLR that is watching 
for COM Release() calls that are taking too long and terminating the threads? 
If so, is there a way around this? The COM object in question really needs to 
have it's Release() call completely executing as it is holding references to 
system services and it they don't get cleaned up during release, the OS will 
become unstable (the volume shadow service on XP goes south).

Note that in my script I do of course call the custom COM object's clean up 
methods proactively so that the object in question has nothing to do in its 
Release() method. I also have a Trap handler to help with this. However I am 
just trying to ensure that the code that cleans up when all else fails (i.e. 
the object was just released without any proper clean up) is not being 
prevented from executing completely.


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I am trying to use the windows installer COM object with powershell
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=======================VB SCRIPT
Dim installer : Set installer = Nothing
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Dim databasePath:databasePath = Wscript.Arguments(0)
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Dim query, view
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=======================PS1 SCRIPT
$file = $args]
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$installer = $null
>>>>> blah.ps1 "blah.wsi"

=========================Types.ps1xml, has to be called using update-
typedate Types.ps1xml before running the ps1 script

        [script removed]  InvokeMethod
 [script removed]         $type = $this.gettype();
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   TypeName: System.__ComObject#{ebe2fdab-6c8f-11d1-a149-00401c6047e4}

Name      MemberType Definition
----      ---------- ----------
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PS C:\>

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