Use `NotifyEndApplication` to re-enable VT mode instead of doing it in `InputLoop.Run` #16612

daxian-dbw · 2021-12-13T22:56:38Z

PR Summary

This is a refactor of the changes in #14413 -- use NotifyEndApplication to re-enable VT mode instead of doing it in InputLoop.Run, so that we run this code only after invoking native commands.

PR Context

I was reviewing the use of NotifyBeginApplication and NotifyEndApplication for some related issues in VS Code extension, and .NET Interactive Notebook, and found that the code to re-enable VT mode in ConsoleHost is not done in NotifyEndApplication, but in InputLoop.Run, so the code runs for every command execution instead of only after executable invocation. This PR attempts to refactor the fix in #14413 to only do it after execution of a native command.

PR Checklist

pull-request-quantifier-deprecated · 2021-12-13T22:56:43Z

This PR has 44 quantified lines of changes. In general, a change size of upto 200 lines is ideal for the best PR experience!

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Label      : Extra Small
Size       : +22 -22
Percentile : 17.6%

Total files changed: 3

Change summary by file extension:
.cs : +22 -22

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daxian-dbw · 2021-12-13T23:00:16Z

src/System.Management.Automation/engine/NativeCommandProcessor.cs

                if (_runStandAlone)
                {
-                    this.Command.Context.EngineHostInterface.NotifyBeginApplication();
-                    _hasNotifiedBeginApplication = true;


If a native process tweaks the window title, it will do so no matter it's running StandAlone or in a pipeline. So, we should actually always call NotifyBeginApplication and NotifyEndApplication before and after running a native command. Therefore, I moved this code out of the if (_runStandAlone) block.

daxian-dbw · 2021-12-13T23:02:52Z

src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHostUserInterface.cs

+                if (outputMode.HasFlag(ConsoleControl.ConsoleModes.VirtualTerminal))
+                {
+                    return true;
+                }


If the outputMode already has VirtualTerminal enabled, no need to set the mode again.

iSazonov · 2021-12-14T03:08:15Z

src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHost.cs

+                    if (ui.SupportsVirtualTerminal)
+                    {
+                        // Re-enable VT mode if it was previously enabled, as a native command may have turned it off.
+                        ui.TryTurnOnVirtualTerminal();


Nit: Interesting, is such console operations expensive?
In line 1105 we have already requested a handle and set mode, now TryTurnOnVirtualTerminal does the operations again. It seems we could do perf optimization.

Very likely not expensive, especially if this is done only after native command execution. The handle is already cached, GetActiveScreenBufferHandle() returns a cached output handle.

daxian-dbw · 2021-12-17T17:39:00Z

@SteveL-MSFT and @anmenaga Can you please review when you have time? Thanks!

ghost · 2021-12-25T02:00:41Z

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

daxian-dbw · 2022-01-03T18:16:51Z

@SteveL-MSFT and @anmenaga gentle ping :) Please review when you have time, thanks!

daxian-dbw · 2022-01-07T01:13:18Z

@SteveL-MSFT and @anmenaga Gentle ping again :) Please take a look when you have time, thanks!

anmenaga

LGTM.
Interesting scenario.

daxian-dbw · 2022-01-14T01:37:32Z

Thanks @anmenaga for taking a look!
@iSazonov I think this PR is ready to merge, thanks!

iSazonov · 2022-01-14T04:07:10Z

Final notices:

Maybe interesting for you End of line cursor position differences when app is run in Windows Terminal microsoft/terminal#8312 (comment) (with related references)
Here all is about output to a console but should we think about input too?

Use NotifyEndApplication to re-enable VT mode instead of doing it in InputLoop.Run, so that we run this code only after invoking native commands

ghost · 2022-02-24T23:33:46Z

🎉v7.3.0-preview.2 has been released which incorporates this pull request.:tada:

Handy links:

Release Notes

Use NotifyEndApplication to re-enable VT mode

5799ce7

daxian-dbw requested a review from SteveL-MSFT December 13, 2021 22:56

daxian-dbw requested a review from anmenaga as a code owner December 13, 2021 22:56

ghost assigned iSazonov Dec 13, 2021

pull-request-quantifier-deprecated bot added the Extra Small label Dec 13, 2021

daxian-dbw commented Dec 13, 2021

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iSazonov approved these changes Dec 14, 2021

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iSazonov added the CL-General Indicates that a PR should be marked as a general cmdlet change in the Change Log label Dec 14, 2021

ghost added the Review - Needed The PR is being reviewed label Dec 25, 2021

ghost removed the Review - Needed The PR is being reviewed label Jan 3, 2022

SeeminglyScience mentioned this pull request Jan 13, 2022

External application leaks something ANSI-Corrupting into PowerShell session #16741

Closed

5 tasks

anmenaga approved these changes Jan 13, 2022

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iSazonov merged commit 186d6be into PowerShell:master Jan 14, 2022

daxian-dbw deleted the refactor branch January 14, 2022 17:12

PatTheMav mentioned this pull request Jan 20, 2022

Redirection of external command output breaks ANSI sequences #16775

Closed

5 tasks

PatTheMav mentioned this pull request Mar 13, 2022

CI: Unified build scripts for all platforms obsproject/obs-deps#98

Merged

6 tasks

SeeminglyScience mentioned this pull request Oct 17, 2022

Select-String doesn't render VT (ANSI) escape sequences in its for-display output with input from external programs on Windows #18294

Closed

5 tasks

Herrmel mentioned this pull request Dec 16, 2022

Streamed executable output prints Ansi Escaping in Write-* Commandlets #18771

Closed

5 tasks

mklement0 mentioned this pull request Feb 7, 2023

Consider implicitly activating VT / ANSI escape-sequence support for native programs in conhost.exe console windows on Windows #19101

Closed

mklement0 mentioned this pull request Mar 30, 2023

Selective disabling/re-enabling of VT support (ANSI escape sequences) is broken #19425

Closed

5 tasks

Herrmel mentioned this pull request Jun 15, 2023

Problems with enabling Virtual Terminal Mode when streaming program output on conhost #19813

Closed

5 tasks

mklement0 mentioned this pull request Dec 11, 2023

conhost.exe console windows on Windows: cmdlets, e.g. Select-String, do not render VT (ANSI) escape sequences in their for-display output with direct input from native (external) programs #20898

Open

5 tasks

Use NotifyEndApplication to re-enable VT mode instead of doing it in InputLoop.Run #16612

Use NotifyEndApplication to re-enable VT mode instead of doing it in InputLoop.Run #16612

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daxian-dbw commented Dec 13, 2021

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Use `NotifyEndApplication` to re-enable VT mode instead of doing it in `InputLoop.Run` #16612

Use `NotifyEndApplication` to re-enable VT mode instead of doing it in `InputLoop.Run` #16612