Implement SetTaskbarProgress for conhost by tanishqtayade · Pull Request #20369 · microsoft/terminal

tanishqtayade · 2026-06-28T06:27:14Z

Summary:
Conhost had an empty SetTaskbarProgress which was TODO stub. Implemented it using ITaskbarList3 so conhost now actually updates the Windows taskbar progress indicator when a VT sequence requests it.

References:
Addresses the TODO in src/host/outputStream.cpp.

Description:
Used the same structure as IslandWindow::SetTaskbarProgress , get the window handle via ServiceLocator, create and cache an ITaskbarList3 instance, call HrInit() before use, and handle all five states (Clear, Set, Error, Indeterminate, Paused). Caches the instance as a member variable instead of creating a new COM object on every call. Also added ShObjIdl.h to precomp.h since ITaskbarList3 lives there.

Validation:
Built locally with Debug x64 ,30 succeeded, 0 failed.

The function was just an empty TODO stub. Hooked it up using ITaskbarList3, same as IslandWindow already does. Caches the COM instance and calls HrInit() before use.

tanishqtayade · 2026-07-02T17:04:46Z

Hi @DHowett this PR has approvals from reviewers with read-only access, but branch protection requires an approval from someone with write access to merge. Could you please take a look and approve if it looks good? All required checks are passing thanks for your time.

DHowett · 2026-07-10T00:29:56Z

Hey, sorry for the delay. Much of the team has been out of the office or distracted of late. This is really cool, I'll make sure we review it soon.

DHowett

in general, we try to avoid having the output handlers do anything with the windowing APIs and instead prefer to create window messages so that the window itself can do it. It's safer from a threading perspective and doesn't couple the I/O path with any of the UI code.

Would you mind following what we did for CM_UPDATE_CLIPBOARD in this very same file? We can probably pack the flags and progress into the lParam of the message. Check out how #18949 did it for some inspiration.

DHowett · 2026-07-10T00:31:12Z

+        flags = TBPF_NOPROGRESS;
+        break;
+    case DispatchTypes::TaskbarState::Set:
+        // cspell:disable-next-line


okay so, as a rule, we do not use cspell. i do not know where "you" may have gotten that idea.

github-advanced-security

check-spelling found more than 20 potential problems in the proposed changes. Check the Files changed tab for more details.

… ITaskbarList3 directly

tanishqtayade · 2026-07-10T11:19:08Z

Hey @DHowett , refactored as per your suggestion.
SetTaskbarProgress in outputStream.cpp now just posts CM_SET_TASKBAR_PROGRESS with state + progress packed into lParam, same pattern as CM_UPDATE_CLIPBOARD. The ITaskbarList3 call is in now Window::_HandleSetTaskbarProgress (window.cpp/hpp), invoked from ConsoleWindowProc on the UI thread. Moved ShObjIdl.h from host/precomp.h to win32/precomp.h accordingly.
Note that I packed state/progress into 16 bits each rather than a 32/32 split, since LPARAM is only 32 bits on x86 - a <<32 shift would've been UB there. Happy to adjust if you'd prefer a different layout.
Re: cspell - added those without actually needing to, this repo doesn't use cspell disable comments as a convention, I just assumed it would based on habit from other projects. Removed them all.

DHowett · 2026-07-10T18:16:52Z

 # MSBuildCache
-/MSBuildCacheLogs/
+/MSBuildCacheLogs/
+vcpkg_installed/


I do not believe our build system puts this in the root folder, and therefore it does not need to be ignored here in the root folder :)

DHowett · 2026-07-10T18:17:30Z

        void _HandleWindowPosChanged(const LPARAM lParam);
        LRESULT _HandleGetDpiScaledSize(UINT dpiNew, _Inout_ SIZE* pSizeNew) const;

+        // Taskbar progress                     // ← ADD THIS SECTION


"ADD THIS SECTION"?

I appreciate you working on this, but I would like to ask you to be sure that I am not the first human to read the code 🙂

DHowett · 2026-07-10T18:18:02Z

 #endif

 #define CM_UPDATE_CLIPBOARD      (WM_USER+20)
+#define CM_SET_TASKBAR_PROGRESS   (WM_USER+21)


it seems you've made an attempt to align these, but it has not worked

DHowett · 2026-07-10T18:18:21Z

@@ -78,4 +80,5 @@ class ConhostInternalGetSet final : public Microsoft::Console::VirtualTerminal::

 private:
    Microsoft::Console::IIoProvider& _io;
+


revert all changes to this file since you have not changed it

DHowett · 2026-07-10T18:20:07Z

 tbc
 tbi
 TBM
+TBPF


curious - we already use TBPF in this codebase. it looks like it's already present in spelling/allow/apis.txt. You can put TBPFLAG in there too.

DHowett · 2026-07-10T18:20:59Z

(Otherwise, this is going in the right direction!)

…n apis.txt, revert unrelated files

tanishqtayade · 2026-07-10T20:55:17Z

Hii @DHowett ,fixed all of these. That ADD THIS SECTION comment was a leftover placeholder from when I was scaffolding the change and moving pieces into window.cpp/window.hpp . I clearly didn't give the diff a close enough read before pushing, fair callout. Cleaned it up along with the rest.
Reverted outputStream.hpp (no actual change needed there), fixed the alignment in CustomWindowMessages.h, moved TBPF/TBPFLAG out of expect.txt since they're already covered in apis.txt, and dropped the vcpkg_installed line from .gitignore.

DHowett · 2026-07-10T21:33:47Z

/azp run

azure-pipelines · 2026-07-10T21:34:00Z

Azure Pipelines successfully started running 1 pipeline(s).

DHowett · 2026-07-10T21:39:43Z

Looks like the code format check failed!

j4james · 2026-07-10T23:10:01Z

@DHowett I strongly suspect this implementation is incorrect. And this may seem harsh, but I think PRs that show no sign of human involvement should just be rejected outright. It's not like the LLM is going to learn anything from the experience while you handhold it through the process of fixing the code.

DHowett · 2026-07-10T23:11:34Z

@j4james you're right. I feel kinda bad doing that, but I do understand that it is costing me my own humanity. Thank you

github-advanced-security AI found potential problems Jun 28, 2026

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Implement SetTaskbarProgress for conhost

4fcb254

The function was just an empty TODO stub. Hooked it up using ITaskbarList3, same as IslandWindow already does. Caches the COM instance and calls HrInit() before use.

tanishqtayade force-pushed the fix/conhost-settaskbarprogress branch from 8a0015e to 4fcb254 Compare June 28, 2026 06:39

G-Deepak-05 approved these changes Jun 28, 2026

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ethanparker436 approved these changes Jun 29, 2026

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DHowett requested changes Jul 10, 2026

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microsoft-github-policy-service Bot added Needs-Author-Feedback The original author of the issue/PR needs to come back and respond to something and removed Needs-Author-Feedback The original author of the issue/PR needs to come back and respond to something labels Jul 10, 2026

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Refactor SetTaskbarProgress to post window message instead of calling…

9e865ea

… ITaskbarList3 directly

tanishqtayade force-pushed the fix/conhost-settaskbarprogress branch from f4143a4 to 9e865ea Compare July 10, 2026 11:13

tanishqtayade requested a review from DHowett July 10, 2026 11:24

DHowett reviewed Jul 10, 2026

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microsoft-github-policy-service Bot added the Needs-Author-Feedback The original author of the issue/PR needs to come back and respond to something label Jul 10, 2026

Fix message value alignment, remove leftover comment, allow TBPFLAG i…

2839b54

…n apis.txt, revert unrelated files

microsoft-github-policy-service Bot removed the Needs-Author-Feedback The original author of the issue/PR needs to come back and respond to something label Jul 10, 2026

tanishqtayade requested a review from DHowett July 10, 2026 20:55

		@@ -78,4 +80,5 @@ class ConhostInternalGetSet final : public Microsoft::Console::VirtualTerminal::

		private:
		Microsoft::Console::IIoProvider& _io;

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tanishqtayade commented Jun 28, 2026 •

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