`Console.ReadKey` behaves differently in .NET 6 and .NET 7-preview.7 comparing to .NET 5 when TERM is set to rxvt

[daxian-dbw]

Description

Description

We got a report in PowerShell repo about "arrow keys not functioning properly in PowerShell 7.2 with rxvt terminals", see PowerShell/PowerShell#16606.

It turns out Console.ReadKey behaves differently in .NET 6 and .NET 7-preview.7 comparing to .NET 5 when TERM is set to rxvt.
In .NET 5, the ConsoleKeyInfo returned for LeftArrow doesn't has any modifiers, as shown below:

However, in .NET 6 and .NET 7-preview.7, the ConsoleKeyInfo returned for LeftArrow has Control and Shift modifiers specified, as shown below:

Note that, this issue was originally reported as #63387, which was closed as completed. However, it's not fixed in .NET 7-preview.7.

Reproduction Steps

1. Run export TERM=rxvt
2. Start PowerShell 7.2.0, or 7.2.1, or 7.3.0-preview.7
3. Try using arrow keys to navigate the cursor position

Expected behavior

LeftArrow and RightArrow should move the cursor left and right;
LeftArrow and RightArrow should go through history commands.

Actual behavior

Arrow keys are not working as expected.
Home and End prints OH and OF respectively.

Regression?

Yes.

Known Workarounds

Setting TERM=xterm would make Console.ReadKey work as expected with rxvt terminals.

Configuration

Which version of .NET is the code running on?
.NET 7-preview.7

What OS and version, and what distro if applicable?
Ubuntu 18.04

What is the architecture (x64, x86, ARM, ARM64)?
x64

Other information

No response

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Issue Details

---

Description

Description

We got a report in PowerShell repo about "arrow keys not functioning properly in PowerShell 7.2 with rxvt terminals", see PowerShell/PowerShell#16606.

It turns out Console.ReadKey behaves differently in .NET 6 and .NET 7-preview.7 comparing to .NET 5 when TERM is set to rxvt.
In .NET 5, the ConsoleKeyInfo returned for LeftArrow doesn't has any modifiers, as shown below:

However, in .NET 6 and .NET 7-preview.7, the ConsoleKeyInfo returned for LeftArrow has Control and Shift modifiers specified, as shown below:

Note that, this issue was originally reported as #63387, which was closed as completed. However, it's not fixed in .NET 7-preview.7.

Reproduction Steps

1. Run export TERM=rxvt
2. Start PowerShell 7.2.0, or 7.2.1, or 7.3.0-preview.7
3. Try using arrow keys to navigate the cursor position

Expected behavior

LeftArrow and RightArrow should move the cursor left and right;
LeftArrow and RightArrow should go through history commands.

Actual behavior

Arrow keys are not working as expected.
Home and End prints OH and OF respectively.

Regression?

Yes.

Known Workarounds

Setting TERM=xterm would make Console.ReadKey work as expected with rxvt terminals.

Configuration

Which version of .NET is the code running on?
.NET 7-preview.7

What OS and version, and what distro if applicable?
Ubuntu 18.04

What is the architecture (x64, x86, ARM, ARM64)?
x64

Other information

No response

Author:	daxian-dbw
Assignees:	-
Labels:	area-System.Console
Milestone:	-

[daxian-dbw]

/cc @adamsitnik

[vcsjones]

Based on the https://github.com/dotnet/runtime/commits/v7.0.0-preview.7.22375.6 tag, it's last commit was July 25th.

The fix wasn't merged until August 1st. f1de614

So it would seem the fix is not present in preview7, however I do see it in the RC1 branch.

[daxian-dbw]

Please keep this issue open until it's verified fixed with RC1 release.

[adamsitnik]

@vcsjones is right, #72193 was not included in Preview 7, but it in RC 1

Now we have tests for these particular keys for rxvt and I am 100% sure they work as expected:

Arrow keys and all modifiers:

runtime/src/libraries/System.Console/tests/KeyParserTests.cs

Lines 1088 to 1107 in 1f6ebd0

	yield return (new byte[] { 27, 91, 68 }, new ConsoleKeyInfo(default, ConsoleKey.LeftArrow, false, false, false)); // LeftArrow
	yield return (new byte[] { 27, 79, 100 }, new ConsoleKeyInfo(default, ConsoleKey.LeftArrow, false, false, true)); // Ctrl+LeftArrow
	yield return (new byte[] { 27, 27, 91, 68 }, new ConsoleKeyInfo(default, ConsoleKey.LeftArrow, false, true, false)); // Alt+LeftArrow
	yield return (new byte[] { 27, 91, 100 }, new ConsoleKeyInfo(default, ConsoleKey.LeftArrow, true, false, false)); // Shift+LeftArrow
	yield return (new byte[] { 27, 27, 91, 100 }, new ConsoleKeyInfo(default, ConsoleKey.LeftArrow, true, true, false)); // Shift+Alt+LeftArrow
	yield return (new byte[] { 27, 91, 65 }, new ConsoleKeyInfo(default, ConsoleKey.UpArrow, false, false, false)); // UpArrow
	yield return (new byte[] { 27, 79, 97 }, new ConsoleKeyInfo(default, ConsoleKey.UpArrow, false, false, true)); // Ctrl+UpArrow
	yield return (new byte[] { 27, 27, 91, 65 }, new ConsoleKeyInfo(default, ConsoleKey.UpArrow, false, true, false)); // Alt+UpArrow
	yield return (new byte[] { 27, 91, 97 }, new ConsoleKeyInfo(default, ConsoleKey.UpArrow, true, false, false)); // Shift+UpArrow
	yield return (new byte[] { 27, 27, 91, 97 }, new ConsoleKeyInfo(default, ConsoleKey.UpArrow, true, true, false)); // Shift+Alt+UpArrow
	yield return (new byte[] { 27, 91, 66 }, new ConsoleKeyInfo(default, ConsoleKey.DownArrow, false, false, false)); // DownArrow
	yield return (new byte[] { 27, 79, 98 }, new ConsoleKeyInfo(default, ConsoleKey.DownArrow, false, false, true)); // Ctrl+DownArrow
	yield return (new byte[] { 27, 27, 91, 66 }, new ConsoleKeyInfo(default, ConsoleKey.DownArrow, false, true, false)); // Alt+DownArrow
	yield return (new byte[] { 27, 91, 98 }, new ConsoleKeyInfo(default, ConsoleKey.DownArrow, true, false, false)); // Shift+DownArrow
	yield return (new byte[] { 27, 27, 91, 98 }, new ConsoleKeyInfo(default, ConsoleKey.DownArrow, true, true, false)); // Shift+Alt+DownArrow
	yield return (new byte[] { 27, 91, 67 }, new ConsoleKeyInfo(default, ConsoleKey.RightArrow, false, false, false)); // RightArrow
	yield return (new byte[] { 27, 79, 99 }, new ConsoleKeyInfo(default, ConsoleKey.RightArrow, false, false, true)); // Ctrl+RightArrow
	yield return (new byte[] { 27, 27, 91, 67 }, new ConsoleKeyInfo(default, ConsoleKey.RightArrow, false, true, false)); // Alt+RightArrow
	yield return (new byte[] { 27, 91, 99 }, new ConsoleKeyInfo(default, ConsoleKey.RightArrow, true, false, false)); // Shift+RightArrow
	yield return (new byte[] { 27, 27, 91, 99 }, new ConsoleKeyInfo(default, ConsoleKey.RightArrow, true, true, false)); // Shift+Alt+RightArrow

Home:

runtime/src/libraries/System.Console/tests/KeyParserTests.cs

Line 1072 in 1f6ebd0

yield return (new byte[] { 27, 91, 55, 126 }, new ConsoleKeyInfo(default, ConsoleKey.Home, false, false, false)); // Home

End:

runtime/src/libraries/System.Console/tests/KeyParserTests.cs

Line 1076 in 1f6ebd0

yield return (new byte[] { 27, 91, 56, 126 }, new ConsoleKeyInfo(default, ConsoleKey.End, false, false, false)); // End

Please keep this issue open until it's verified fixed with RC1 release.

@daxian-dbw RC1 is going to be released in four days (13th of September) Could you please test PowerShell with RC1 and re-open it if needed? We close all the issues once PR with a fix gets merged (it lowers the bookkeeping cost on our end).

[daxian-dbw]

@adamsitnik Thanks for confirming! I opened this issue only because the original one was locked and hence I cannot ask for confirmation. I will test with RC1 once it's out.

[daxian-dbw]

@adamsitnik This issue still reproduces with PowerShell built against .NET 7-RC1, on Ubuntu 18.04 WSL2. The env var TERM is set to rxvt as in the repro step

Here are the observed behaviors:

1. When directly running [Console]::ReadKey($true) in PowerShell, it returns the expected ConsoleKeyInfo results when pressing arrow keys (same as with PowerShell 7.2.6 that is built against .NET 6)
2. When running a console application that simply calls Console.ReadKey(true) (with .NET 7-RC1), it returns the expected ConsoleKeyInfo results when pressing arrow keys (didn't try building and running the application with .NET 6)
3. When calling Console.ReadKey(true) from PSReadLine which is running in the same PowerShell session, it returns the arrow ConsoleKeyInfo with Shift | Control modifiers. (same as with PowerShell 7.2.6 that is built against .NET 6)

This is really puzzling ☹️ I would really appreciate your help to understand the root cause of this.

[adamsitnik]

When calling Console.ReadKey(true) from PSReadLine which is running in the same PowerShell session, it returns the arrow ConsoleKeyInfo with Shift | Control modifiers. (same as with PowerShell 7.2.6 that is built against .NET 6)

@daxian-dbw I need to attach a debugger to find out why. Is there any chance you could describe how I can repro that? (What to build and how to run PSReadLine)?