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

[daxian-dbw]

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 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, the the ConsoleKeyInfo returned for LeftArrow has Control and Shift modifiers specified, as shown below:

---

It's not like Console.ReadKey always work properly in .NET 5 with rxvt terminals, for example, Home returns Escape+H (it returns OH in .NET 6), and End returns Escape+F (it returns OF in .NET 6), instead of Home and End as expected.

But it's been reported that setting TERM=xterm would make Console.ReadKey work as expected with regard to arrow keys with rxvt terminals -- see PowerShell/PowerShell#16606 (comment).

So, are rxvt terminals really supported by .NET 5/6? If so, what configurations should be done to make it work properly with Console.ReadKey?

Reproduction Steps

1. Run export TERM=rxvt
2. Start PowerShell 7.2.0 or 7.2.1
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

No response

Other information

No response

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Issue Details

---

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 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, the the ConsoleKeyInfo returned for LeftArrow has Control and Shift modifiers specified, as shown below:

---

It's not like Console.ReadKey always work properly in .NET 5 with rxvt terminals, for example, Home returns Escape+H (it returns OH in .NET 6), and End returns Escape+F (it returns OF in .NET 6), instead of Home and End as expected.

But it's been reported that setting TERM=xterm would make Console.ReadKey work as expected with rxvt terminals.

So, are rxvt terminals really supported by .NET 5/6? If so, what configurations should be done to make it work properly with Console.ReadKey?

Reproduction Steps

1. Run export TERM=rxvt
2. Start PowerShell 7.2.0 or 7.2.1
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

No response

Other information

No response

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

[B-Art]

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 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, the the ConsoleKeyInfo returned for LeftArrow has Control and Shift modifiers specified, as shown below:

It's not like Console.ReadKey always work properly in .NET 5 with rxvt terminals, for example, Home returns Escape+H (it returns OH in .NET 6), and End returns Escape+F (it returns OF in .NET 6), instead of Home and End as expected.

But it's been reported that setting TERM=xterm would make Console.ReadKey work as expected with rxvt terminals.

So, are rxvt terminals really supported by .NET 5/6? If so, what configurations should be done to make it work properly with Console.ReadKey?

Reproduction Steps

1. Run export TERM=rxvt
2. Start PowerShell 7.2.0 or 7.2.1
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

No response

Other information

No response

In expected behavior:
You mean up arrow ⬆️ and down arrow ⬇️ for going through history.

[daxian-dbw]

You mean up arrow ⬆️ and down arrow ⬇️ for going through history.

Yes, it was reported that arrow keys worked as expected after setting TERM=xterm. I have updated the PR description to make this more clear:

But it's been reported that setting TERM=xterm would make Console.ReadKey work as expected with regard to arrow keys with rxvt terminals -- see PowerShell/PowerShell#16606 (comment).

[maxim-lobanov]

Any updates on this issue? It causes issues in PowerShell Core 7.2 because of update to .NET 6.