Start-DebugAttachSession without parameters "hangs"

Prerequisites

• I have written a descriptive issue title.
• I have searched all open and closed issues to ensure it has not already been reported.
• I have read the troubleshooting guide.
• I am sure this issue is with the extension itself and does not reproduce in a standalone PowerShell instance.
• I have verified that I am using the latest version of Visual Studio Code and the PowerShell extension.
• If this is a security issue, I have read the security issue reporting guidance.

Summary

Start-DebugAttachSession without parameters "hangs".

PowerShell Version

Name                           Value
----                           -----
PSVersion                      7.5.4
PSEdition                      Core
GitCommitId                    7.5.4
OS                             Microsoft Windows 10.0.26200
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Name             : Visual Studio Code Host
Version          : 2025.5.0
InstanceId       : 34bb8444-87b8-4ee9-862b-d008a055e1c1
UI               : System.Management.Automation.Internal.Host.InternalHostUserInterface
CurrentCulture   : en-GB
CurrentUICulture : en-US
PrivateData      : Microsoft.PowerShell.ConsoleHost+ConsoleColorProxy
DebuggerEnabled  : True
IsRunspacePushed : False
Runspace         : System.Management.Automation.Runspaces.LocalRunspace

Visual Studio Code Version

1.107.0
618725e67565b290ba4da6fe2d29f8fa1d4e3622
x64

Extension Version

ms-vscode.powershell@2025.5.0

Steps to Reproduce

• Start debugging with the PowerShell Interactive profile.
• In the debug terminal invoke Start-DebugAttachSession

Expected result
VSCode shows the dropdown for choosing a process to attach.

Per Start-DebugAttachSession

If -ProcessId or -CustomPipeName is not specified, the debug client will prompt for process to connect to.

Actual result
The command "hangs". Interestingly, when it is terminated by Ctrl+C, the expected dropdown for choosing a process appears, but it's too late, of course, the command is terminated.

Start by reproducing the issue with the PowerShell Interactive profile and the Start-DebugAttachSession entry point. Read module/docs/Start-DebugAttachSession.md in PowerShellEditorServices to confirm the prompt behavior. Done means invoking the command without parameters shows the process-selection dropdown without requiring Ctrl+C.