Resolve -WindowStyle Hidden console flashing

[iSazonov]

PR Summary

Fix #3028

PR Context

#10962 is direct implementation of pwshw idea. pwshw is only one option from many in the complex topic dicussed in #3028. The PR seems add more flexibility and allow to experiment with console, non-console, pseudo-console and GUI modes, allow to implement pwshw in the same way as we did for preview-pwsh, and also fix -WindowStyle Hidden scenario.

Update: I think follow work should be:

• create xUnit tests for command line parser
• refactor command line parser
  • make it static
  • move out execution code from parser (parser should only parse)
  • merge EarlyParser and parser

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• User-facing changes
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    • Issue filed:
• Testing - New and feature
  • N/A or can only be tested interactively
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• Tooling
  • I have considered the user experience from a tooling perspective and don't believe tooling will be impacted.
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  • I have considered the user experience from a tooling perspective and enumerated concerns in the summary. This may include:
    • Impact on PowerShell Editor Services which is used in the PowerShell extension for VSCode (which runs in a different PS Host).
    • Impact on Completions (both in the console and in editors) - one of PowerShell's most powerful features.
    • Impact on PSScriptAnalyzer (which provides linting & formatting in the editor extensions).
    • Impact on EditorSyntax (which provides syntax highlighting with in VSCode, GitHub, and many other editors).

[daxian-dbw]

@iSazonov Please add description/context for this PR. Also, #10962 is also for fixing #3028, so what is the difference between your fix and that one?

[iSazonov]

@daxian-dbw #10962 is direct implementation of pwshw idea. pwshw is only one option from many in the complex topic dicussed in #3028. The PR seems add more flexibility and allow to experiment with console, non-console, pseudo-console and GUI modes, allow to implement pwshw in the same way as we did for preview-pwsh, and also fix -WindowStyle Hidden scenario.

[daxian-dbw]

You'd better add the PR description about what you are doing in this PR, so a reviewer would know.

[iSazonov]

@daxian-dbw Already done.

Update: I think follow work should be:

• create xUnit tests for command line parser
• refactor command line parser
  • make it static
  • move out execution code from parser (parser should only parse)
  • merge EarlyParser and parser

[DHowett-MSFT]

Just so you’re aware, attaching to the parent process’s console as a Windows subsystem application (WinExe) will cause handle fighting where half your input will go to the parent and half to the child, and all output will be intermixed. This is because the parent, usually cmd or another instance of powershell will not wait for a spawned Windows subsystem application to exit.

You’ll probably see this:

C:\> pwsh
PowerShell 7.0.0
C:\> PS C:\>

(One prompt from CMD, one from powershell, both running and reading input simultaneously.)

This is impossible to work around without...

1. A generic solution in the operating system
2. A hack where powershell knows that it’s spawning another version of powershell, and waits for it to finish (working around the problem only for the PS->PS case.)

[DHowett-MSFT]

Attaching back to the parent’s console handle can also make the console fail to exit because a Windows subsystem application is still attached to it. This happens when you run code from cmd and then type in exit. CMD exits and the window remains because VSCode reattaches to its parent’s console handle.

[iSazonov]

@DHowett-MSFT Thanks! The scenario you describe is "Start-Process -NoNewWindow". We have an issue for it. I agree that we can not resolve it in simple way.
Original issue for the PR asks to address a scenario like scheduled task in user session so that user does not see PowerShell window. In the PR I try to demo how simple we can manually allocate a console to resolve the ask if no user IO is implied.

[ghost]

This pull request has been automatically marked as Review Needed because it has been there has not been any activity for 7 days.
Mainainer, Please provide feedback and/or mark it as Waiting on Author

[ghost]

Open PRs should not be assigned to milestone, so they are not assigned to the wrong milestone after they are merged. For backport consideration, use a backport label.

[ghost]

This pull request has been automatically marked as Review Needed because it has been there has not been any activity for 7 days.
Maintainer, please provide feedback and/or mark it as Waiting on Author