Description
f### Prerequisites
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Steps to reproduce
Note:
-
The repro below uses COM; I suspect - but haven't verified - that any unmanaged resources that aren't explicitly released are affected.
-
I would expect at least jobs that complete by themselves to auto-release such resources; ideally also when
Stop-Job,Remove-Job -Forceis used (don't know about the technical feasibility;Stop-Processapplied to a regular session forcefully kills it and therefore does not auto-release).-
That regular sessions do auto-release can be verified by setting
$useJobsto$falsebelow and re-running the script, which uses CLI calls instead of jobs. -
Curiously,
ForEach-Object -Parallelis seemingly not affected; in the following example the Excel processes do eventually disappear:Stop-Process -Name excel -ea ignore; 1, 2 | ForEach-Object -Parallel { $xl = New-Object -ComObject Excel.Application; $xl.Name; Start-Sleep 5 }
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# Make sure no Excel processes are running
Get-Process -ErrorAction Ignore Excel | Stop-Process -Force -ErrorAction Stop
# A script block that creates a new Excel process via COM, assigns it to a variable, and waits 2 secs.
# before exiting (to ensure that it isn't garbage collected right away).
$sb = { $xl = New-Object -ComObject Excel.Application; $xl.Name; Start-Sleep 2 }
# Set this to $false to use CLI calls instead, which work correctly.
$useJobs = $true
if ($useJobs) {
Write-Verbose -Verbose '--- Creating a background and a thread job each of which creates an Excel process via COM...'
$jobs = (Start-Job $sb), (Start-ThreadJob $sb)
} else {
Write-Verbose -Verbose '--- Calling the CLIs (powershell.exe and pwsh.exe) each of which create an Excel process via COM...'
powershell -NoProfile $sb
pwsh -NoProfile $sb
}
if ($useJobs) {
$jobs | Receive-Job -Wait -AutoRemoveJob
}
# Wait a while to allow extra time for the COM resources to be released,
# which should result in the termination of the Excel processes.
Write-Verbose -Verbose 'Sleeping 30 secs. to wait for release of COM resources...'
Start-Sleep 30
# Now there should be NO Excel processes.
Write-Verbose -Verbose '--- Excel processes after (there should be no output)...'
Get-Process -ErrorAction Ignore ExcelExpected behavior
VERBOSE: --- Creating a background and a thread job each of which creates an Excel process via COM...
Microsoft Excel
Microsoft Excel
VERBOSE: Sleeping 30 secs. to wait for release of COM resources...
VERBOSE: --- Excel processes after (there should be no output)...That is, the two Excel processes should eventually terminate due to auto-release of the COM wrapper.
Actual behavior
VERBOSE: --- Creating a background and a thread job each of which creates an Excel process via COM...
Microsoft Excel
Microsoft Excel
VERBOSE: Sleeping 30 secs. to wait for release of COM resources...
VERBOSE: --- Excel processes after (there should be no output)...
NPM(K) PM(M) WS(M) CPU(s) Id SI ProcessName
------ ----- ----- ------ -- -- -----------
65 71.33 233.75 1.17 5900 12 EXCEL
66 72.31 234.75 0.88 10488 12 EXCELThat is, the two Excel processes linger, because the COM wrapper was never released.
Error details
No response
Environment data
PowerShell 7.5.0-preview.5Visuals
No response