System.Diagnostics.Process.GetProcessById() returns Process objects for non-running processes #66096
Description
Description
PowerShell uses System.Diagnostics.Process.GetProcessById API to obtain process information about running processes. Before .NET 7.0.100-preview.1.22110.4, this API would throw a System.ArgumentException for non-existent processes or for processes that have recently exited. But with .NET 7, this API now sometimes returns a process object for non-running processes with HasExited set to True.
This is a change in behavior that has caused some PowerShell tests to fail.
Reproduction Steps
- Start two instances of PowerShell shell, of the latest preview (
7.3.0-preview.2). - This preview version of PowerShell is built with .NET version
7.0.100-preview.1.22110.4 - Get the two instances process Ids by typing
$PIDin each shell version.
PS > $PID
31412
PS > $PID
24672- In one shell instance get the process object of the other instance via .NET API
PS > $PID
31412
PS > [System.Diagnostics.Process]::GetProcessById(24672)
NPM(K) PM(M) WS(M) CPU(s) Id SI ProcessName
------ ----- ----- ------ -- -- -----------
70 54.65 96.04 2.91 24672 2 pwsh- Exit the PowerShell instance with process Id
24672, and use the .NET API again to obtain the process object.
PS > [System.Diagnostics.Process]::GetProcessById(24672)
NPM(K) PM(M) WS(M) CPU(s) Id SI ProcessName
------ ----- ----- ------ -- -- -----------
0 0.00 0.00 3.08 24672
PS > ([System.Diagnostics.Process]::GetProcessById(24672)).HasExited
TrueExpected behavior
System.Diagnostics.Process.GetProcessById(24672) should not return a process object for a non-running process, and should instead throw an ArgumentException error.
PS C:\> [System.Diagnostics.Process]::GetProcessById(24672)
MethodInvocationException: Exception calling "GetProcessById" with "1" argument(s): "Process with an Id of 24672 is not running."Actual behavior
The API returns a process object for a non-existent process
PS C:\> [System.Diagnostics.Process]::GetProcessById(24672)
NPM(K) PM(M) WS(M) CPU(s) Id SI ProcessName
------ ----- ----- ------ -- -- -----------
0 0.00 0.00 3.08 24672
PS C:\> ([System.Diagnostics.Process]::GetProcessById(24672)).HasExited
TrueRegression?
Yes, this is a regression in behavior to .NET 6.
Known Workarounds
We can update PowerShell code account for this behavior, but it is not clear if this change in behavior is intended or correct.
Configuration
.NET version:
7.0.100-preview.1.22110.4
PowerShell:
PS C:\> $PSVersionTable
Name Value
---- -----
PSVersion 7.3.0-preview.2
PSEdition Core
GitCommitId 7.3.0-preview.2-9-gee6bc9527c2596f048088fa7b396d2664a11ad08
OS Microsoft Windows 10.0.19044
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
WSManStackVersion 3.0Other information
No response