starred/terminal
1
0
Fork 0
mirror of https://github.com/microsoft/terminal.git synced 2026-09-25 08:24:54 +00:00
Code Issues 19.0k Packages Projects Releases 20 Wiki Activity

Re-enable support for DECKPAM #21203

New Issue
Open
opened 2026-01-31 07:36:22 +00:00 by claunia · 2 comments
claunia commented 2026-01-31 07:36:22 +00:00
Owner
Copy Link

Originally created by @zadjii-msft on GitHub (Feb 6, 2024).

This was originally tracked in #16506.
Support was added in #16511.
But turns out people didn't expect the Terminal to actually be like, compliant: #16654

So now we're gonna add a setting to be able to manually enable/disable support for toggling this mode.

The trick here? ConPTY is the thing that's going to need to do the input translation, not the Terminal. So, the Terminal needs a way to tell conpty (at runtime)1 if this is a mode that's allowed or not. And that, we don't have a good system set up for currently.

  1. Leonard keeps terrifyingly calling this ConPTY IOCTL ↩︎

Originally created by @zadjii-msft on GitHub (Feb 6, 2024). This was originally tracked in #16506. Support was added in #16511. But turns out people didn't expect the Terminal to actually be like, compliant: #16654 So now we're gonna add a setting to be able to manually enable/disable support for toggling this mode. The trick here? ConPTY is the thing that's going to need to do the input translation, not the Terminal. So, the Terminal needs a way to tell conpty (at runtime)[^1] if this is a mode that's allowed or not. And that, we don't have a good system set up for currently. [^1]: Leonard keeps terrifyingly calling this ConPTY IOCTL
claunia added the Help WantedIssue-TaskIn-PRArea-InputArea-VTProduct-Terminal labels 2026-01-31 07:36:23 +00:00
claunia commented 2026-01-31 07:36:24 +00:00
Author
Owner
Copy Link

@zadjii-msft commented on GitHub (Feb 6, 2024):

A thought: if we made the setting not necessarily hot reload, we could use the --flag as discussed in #15504, #1802 to statically initialize conpty with or without support for DECKPAM

@zadjii-msft commented on GitHub (Feb 6, 2024): A thought: if we made the setting not necessarily hot reload, we could use the `--flag` as discussed in #15504, #1802 to statically initialize conpty with or without support for DECKPAM
claunia commented 2026-01-31 07:36:25 +00:00
Author
Owner
Copy Link

@j4james commented on GitHub (Feb 6, 2024):

On the broader issue of passing settings from the conpty terminal down to conhost, I think it's worth considering some of the other places we may want to use it, because the different use cases may influence the way we choose to implement it.

There have been a couple of other cases similar to DECKPAM, where users have wanted to block a particular mode. One common one is cursor blinking (mode ?12), which comes up quite a lot (these are just some examples):

Another less common one is the alternate screen buffer (mode ?1049), usually in relation to the screen multiplexer:

Then there are the situations where conhost needs to report state that it doesn't know about, because that state is initialized (and potentially updated) by the conpty client.:

While the modes would probably be OK if only initialized at startup, for things like the palette and cursor shape I think it's quite important to support real-time updates, because the user will see those changes immediately, and will expect any query APIs to reflect what they're seeing.

And the other thing to consider is how this could work (if at all) when conpty is used as the basis for a telnet/ssh server. There's no opportunity there for the terminal to pass flags on the command line, or over a ioctl-like backchannel (at least as far I know).

One my initial ideas what that this could be handled by querying the connected conpty terminal on startup. That way we could use standard VT sequences, which should just work automatically with most conpty clients. But if we want real-time updates, that's not going to cut it - some mechanism for pushing updates from the terminal side would be required.

But maybe we just have to accept that the telnet/ssh situation will never be perfect.

@j4james commented on GitHub (Feb 6, 2024): On the broader issue of passing settings from the conpty terminal down to conhost, I think it's worth considering some of the other places we may want to use it, because the different use cases may influence the way we choose to implement it. There have been a couple of other cases similar to `DECKPAM`, where users have wanted to block a particular mode. One common one is cursor blinking (mode ?12), which comes up quite a lot (these are just some examples): * #10754 * #10919 * #11209 * #12372 Another less common one is the alternate screen buffer (mode ?1049), usually in relation to the *screen* multiplexer: * #13670 * #13703 Then there are the situations where conhost needs to report state that it doesn't know about, because that state is initialized (and potentially updated) by the conpty client.: * #3718 * #10639 * #11946 * Querying the current cursor shape with `DECRQSS` (I don't think this is tracked anywhere). While the modes would probably be OK if only initialized at startup, for things like the palette and cursor shape I think it's quite important to support real-time updates, because the user will see those changes immediately, and will expect any query APIs to reflect what they're seeing. And the other thing to consider is how this could work (if at all) when conpty is used as the basis for a telnet/ssh server. There's no opportunity there for the terminal to pass flags on the command line, or over a ioctl-like backchannel (at least as far I know). One my initial ideas what that this could be handled by querying the connected conpty terminal on startup. That way we could use standard VT sequences, which should just work automatically with most conpty clients. But if we want real-time updates, that's not going to cut it - some mechanism for pushing updates from the terminal side would be required. But maybe we just have to accept that the telnet/ssh situation will never be perfect.
Sign in to join this conversation.
No Branch/Tag Specified
Branches Tags
Labels
Clear labels
⛺ Reserved
A11yCO
A11yMAS
A11ySev1
A11ySev2
A11ySev3
A11yTTValidated
A11yUsable
A11yVoiceAccess
A11yWCAG
Area-Accessibility
Area-AtlasEngine
Area-AzureShell
Area-Build
Area-Build
Area-Chat
Area-CmdPal
Area-CodeHealth
Area-Commandline
Area-CookedRead
Area-DefApp
Area-Extensibility
Area-Fonts
Area-GroupPolicy
Area-i18n
Area-Input
Area-Interaction
Area-Interop
Area-Localization
Area-Output
Area-Performance
Area-Portable
Area-Quality
Area-Remoting
Area-Rendering
Area-Schema
Area-Server
Area-Settings
Area-SettingsUI
Area-ShellExtension
Area-ShellExtension
Area-ShellExtension
Area-Suggestions
Area-Suggestions
Area-TerminalConnection
Area-TerminalControl
Area-Theming
Area-UserInterface
Area-VT
Area-Windowing
Area-WPFControl
AutoMerge
Blocking-Ingestion
Culprit-Centennial
Culprit-WinUI
Disability-All
Disability-Blind
Disability-LowVision
Disability-Mobility
External-Blocked-WinUI3
Fixed
Gathering-Data
good first issue
HCL-E+D
HCL-WindowsTerminal
Help Wanted
Impact-Compatibility
Impact-Compliance
Impact-Correctness
Impact-Visual
In-PR
InclusionBacklog
InclusionBacklog-Windows TerminalWin32
InclusionCommitted-202206
Issue-Bug
Issue-Docs
Issue-Feature
Issue-Feature
Issue-Question
Issue-Samples
Issue-Scenario
Issue-Task
Needs-Attention
Needs-Author-Feedback
Needs-Bisect
Needs-Discussion
Needs-Repro
Needs-Tag-Fix
Needs-Tag-Fix
Needs-Triage
No-Recent-Activity
Priority-0
Priority-1
Priority-2
Priority-3
Product-Cmd.exe
Product-Colortool
Product-Colortool
Product-Colortool
Product-Conhost
Product-Conpty
Product-Meta
Product-Powershell
Product-Terminal
Product-WSL
pull-request
Mirrored from GitHub Pull Request
 Resolution-Answered
Resolution-By-Design
Resolution-Duplicate
Resolution-External
Resolution-Fix-Available
Resolution-Fix-Committed
Resolution-No-Repro
Resolution-Won't-Fix
Severity-Blocking
Severity-Crash
Severity-DataLoss
spam
this-will-be-a-breaking-change
Tracking-External
WindowsTerminal_Win32
Work-Item
zAskModeBug
zInbox-Bug
No Label Area-Input Area-VT Help Wanted In-PR Issue-Task Product-Terminal
Milestone
No items
No Milestone
Projects
Clear projects
No project
Assignees
Clear assignees
claunia
No Assignees
1 Participants
Notifications
Due Date
No due date set.
Dependencies

No dependencies set.

Reference: starred/terminal#21203
Delete Branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?