These changes provide the ability to debug remote running scripts started with the Invoke-Command cmdlet. The design is event based and provides new public events that allow subscribers to be notified when an Invoke-Command remote session is ready for debugging. Since Invoke-Command allows running scripts on multiple targets at once (fan-out) the notification event is raised for each remote session as it becomes ready for debugging. The subscriber to these events will be a script debugger implementation (such as PowerShell console, ISE, or VSCode) and will handle all debugging details such as simultaneously debugging multiple remote sessions at once in separate windows.
But these changes also include an internal implementation which is used by default if host debuggers don't want to handle the debugging details. This internal implementation is what PowerShell console, ISE uses so they can have this new behavior without having to modify their debugger implementations. The internal implementation serializes each remote session of Invoke-Command so that they can be debugged one at a time. The remote session debugger is "pushed" onto the internal debugger stack so that debugging transitions to the remote session. Existing debugging commands work so that the "quit" debugging command will stop the current remote session script from running and allow the next remote session to be debugged. Similarly the "continue" debugging command allows the script to continue running outside step mode and again go to the next remote session for debugging. The "stepout" debugging command steps out of all Invoke-Command remote sessions and lets the script continue to run for each remote session in parallel as they are normally run.
The purpose of Invoke-Command step-in remote debugging is allow seamless debugging of a local script that calls Invoke-Command on remote targets. But there is also a new Invoke-Command "-RemoteDebug" parameter that lets you Invoke-Command on the command line and have it drop directly into the debugger.
An example from the PowerShell command line looks like this:
```
PS C:\> C:\TestICM.ps1
Entering debug mode. Use h or ? for help.
Hit Command breakpoint on 'Invoke-Command'
At C:\TestICM.ps1:2 char:1
+ Invoke-Command -cn $computerName,paulhig-3 -File c:\LinuxScript.ps1
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[DBG]: PS C:\>> list
1: $computerName = "localhost"
2:* Invoke-Command -cn $computerName,paulhig-3 -File c:\LinuxScript.ps1
3: "Test Complete!"
[DBG]: PS C:\>> stepin
At line:1 char:1
+ Write-Output "Running script on Linux!"
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[paulhig-3]:[DBG]: [Process:14072]: [Runspace5]: PS C:\Users\paulhi\Documents>
```
Notice that the debugger "stepin" command transitioned from local script debugging to debugging the remote session on computer "paulhig-3", as can be seen by the change in the debugger prompt.
You can also do this from the command line to drop directly into the debugger
```
Invoke-Command -cn localhost -Script $scriptblock -RemoteDebug
```
These changes also remove an old behavior that was incompatible with this new step-in feature. Previously if a remote session running script hit a break point it would stop in the debugger and go to the "disconnected session" state. This was to allow the user to reconnect using Enter-PSSession and then interactively debug the remote session script. This behavior has been removed and now the user needs to attach a debugger using the newer Debug-Runspace cmdlet.
When a TypeTable is created it includes the types from type files provided along with references to the type files. When the InitialSessionState (ISS) object processes these types it reads the type files again and ends up with duplicate type entries. PowerShell V5.1 ISS type processing was re-written to improve performance and no longer removes duplicate types, so that this scenario (runspace ISS reuse) results in errors causing a regression.
The fix is to copy only type data when a TypeTable is passed to the ISS.
* RFC 0010 SSH remoting cmdlet updates.
* Tweaks to SSH remoting cmdlets
* SSHTransport parameter is now optional instead of mandatory. Aded fix for CoreCLR entry point when hosted in SSH as a subsystem.
* Added tests
* Code review feedback
* Code review comment changes
* Making SSHTransport switch parameter mandatory because otherwise existing Invoke-Command parameter set
* The new SSH parameter set was causing legacy positional based parameters to no longer work. This fix separates the SSH parameter sets from the existing WinRM parameter sets.
* Fixed region name spelling error.
* Fix for Win32-OpenSSH break when hosting PowerShell in server mode as an SSH subsystem.
* Refactored to use null PSHostUserInterface implementation
* Implemented code review comments
* Fix host remote test InvokeOnRunspace to work with AppVeyor
* Updated to use new local account for remoting tests.
* Set the LocalAccountTokenFilterPolicy as needed.
* Adding verbose messages for debugging.
* Storing creds using Export-CliXml
* Added CITravis skip for Windows only remoting test
* Moving tests back to 'Feature' scope
* Added AppVeyor environment variable check to prevent account creation on non-appveyor configurations
* Removed It block in BeforeAll block
* Moving tests back to 'Feature'
* Merge TFS 2064268: Under UMCI PowerShell should not block nested cmdlet invocation via runspace
* Update SessionState.cs
Fixed ExecutionContext property name error.
Paul Higinbotham