Adopt chat sessions controller API for copilot cli

[mjbvz]

We're replacing the chat sessions provider based API with a new controller based API (see ChatSessionItemController in src/extension/vscode.proposed.chatSessionsProvider.d.ts)

This API moves to a managed object model instead of a provider based model. This should be easier to work with and also let us expose new API functionality, such as callbacks when a chat session item is archived

General migration guide:

• Instead of calling registerChatSessionItemProvider, create a controller with createChatSessionItemController

• provideChatSessionItems becomes essentially the refreshHandler. Instead of returning the items, you should update controller.items

• Whenever you create a chat session item, use createChatSessionItem. This makes sure the item is managed. You can set properties directly on it to update the item

Let me know if you run into any bugs or have any questions about using the new API!

[mjbvz]

Oh actually looks like you already did this. Thanks @DonJayamanne! Let me know if you run into any issues with the new API

[DonJayamanne]

Testing

Testing

• Session with Pending input
  • Verify you can see pending inputs
  • Open a different session and come back and you should still see the pending input
• Streaming output
  • Run a long running prompt with lot of thinking/streaming of outputs (e.g. code review or plan a large chagne)
  • Verify you can see streaming output
  • Open a different session and come back and you should still see the steaming output
• Steering
  • Send first prompt
  • Immediately after this send a steering message, and verify this works
  • TIP: Try something like planning a large change, and then send steering message asking to prefix each line with an emoji or the like
• Queuing of messages
  • Send first prompt
  • Immediately after this queue another message, simple as what is 1+2
  • Verify the message is queued and is processed
• Change prompt notification
  • When creating a new CLI Worktree session and if you have changes in the active branch you should be prompted to migrate your changes
• Archiving
  • Start a new session with a fairly long running prompt
  • Immediately archive this session
  • Verify it is archived
  • Reload VS Code and verify it is still archived
  • Note: You must archive before the turn completes
• Rename
  • Start a new session
  • Immediately rename this session
  • Verify it is renamed
  • Wait for turn to complete, then reload VS Code and verify it still displays your custom title
• Delete
  • Start a new session
  • Immediately delete this session
  • Verify it is deleted
  • Wait for turn to complete, then reload VS Code and verify it still displays your custom title
• Session Context menus
  • Start a new session with a fairly long running prompt
  • Test each of the following context menus
  • Open Session in New Window
  • Open Session in Terminal
  • Copy Session Branch Name
  • Resume in Terminal
  • Note: You test the menus before the turn completes

[DonJayamanne]

Enable following settings

  "github.copilot.chat.cli.branchSupport.enabled": true,
  "github.copilot.chat.cli.sessionController.enabled": true,

Completed

• Ability to filter/refresh the values in an option based on the selection of another option @mjbvz
  • Open empty window in Insiders
  • Open chat input and select Copilot CLI
  • We get two options workspace/worktree and list of folders/repos
  • Select worktree from first dropdown
  • Select vscode from second dropdown
  • There should be a 3rd dropdown that displays branches from vscode repo
    (Note: Currently the option doesn't appear, but i need a way to filter the list)
    Similarly if a non-git repo is selected i want to disable the worktree/workspace option
• ChatSessionInputState.ChatSessionInputState doesn't fire @mjbvz
• ChatSessionProviderOptionGroup.onSearch can be removed @mjbvz Remove support for searchable option groups  #306515
  • This isn't used anywhere
• ChatSessionProviderOptionGroup.searchable can be removed @mjbvz Remove support for searchable option groups  #306515
  • This isn't used anywhere
• Ability to update options and disable them @mjbvz
  • When starting a new session i need the ability to update the options and disable them (to prevent user from making changes)
  • Rarely, if things go wrong, I want the ability to re-enable the options (i.e. allow user to change them again)
  • I believe enabling/disabling is possible, what we're missing is the ability to refresh the options
• ChatSessionContext.initialSessionOptions Pass this or similar property with all option values in every chat request @mjbvz
  • Claude Code is a good example, even for existing sessions we have options that are read-write
  • Currently we track the options using the provideHandleOptionsChange method which is deprecated
• Groups do not appear for existing CLI sessions @mjbvz
  • getChatSessionInputState is getting called for existing sessions, however the options aren't rendered
• Command handler get the untitled Uri as the first argument @mjbvz
  Note: Two issues here, the Uri is untitled uri and the argument is not the context object.
  Based on comments I should get something else

* For extensions that use the new `provideChatSessionInputState` API, these commands are passed a context object
`{ inputState: ChatSessionInputState; sessionResource: Uri | undefined }` that they can use to determine which session and options they are being invoked for.

• onDidChange event gets fired, however the selected property of the groups are not updated to reflect users selection @mjbvz

Hence I don't have a way of knowing what the user selected.
You might already be aware of this, also noticed that this is still a WIP (based on following comments)

// Temporary workaround: input state changes for one resource are propagated to all
// input states for the same resource type until we can make this session-specific.

Items to address

• Opening an existing session doesn't display any of the options @DonJayamanne (blocked on below)
• Initializing selected property after handling onDidChange doesn't work, I can see the items in the dropdown have change, however the selected value in the UI is still the old value @mjbvz
  Not a blocker but more of a UI bug.
• I still need to return options in provideChatSessionContent @mjbvz
  This is NOT a blocker, but debt/cleanup
  This property still needs to be returned so that I can disable the dropdowns.

readonly options?: Record<string, string | ChatSessionProviderOptionItem>;

I think what we're missing is in the return val.ue of ChatSessionItemController.getChatSessionInputState
The return value contains ChatSessionProviderOptionGroup
However there's no way to disable a dropdown, today we have the ability to disable dropdown items, but not the entire dropdown.
Having a locked or similar property on this would probably make it unnecessary to return (allowing deprecation of that) readonly options?: Record<string, string | ChatSessionProviderOptionItem>;

[mjbvz]

Ability to filter/refresh the values in an option based on the selection of another option

There should be a ChatSessionInputState.onDidChange helper that is fired for this. However it's not currently hooked up correctly. Working on this now

---

ChatSessionContext.initialSessionOptions Pass this or similar property with all option values in every chat request

Good idea. let me add the input state to ChatSessionContext too

---

Ability to update options and disable them

Try changing the input state object values. You have to reset the groups property like this:

controller.getChatSessionInputState = async (sessionResource, context, token) => {
	const groups = sessionResource ? await this.buildExistingSessionInputStateGroups(sessionResource, token) : await this.provideChatSessionProviderOptionGroups(context.previousInputState);
	const state = controller.createChatSessionInputState(groups);

	const first = state.groups.at(0);

       // Simulate changes async
	setInterval(() => {
		if (first) {
			if (state.groups.includes(first)) {
				state.groups = state.groups.slice(1);
			} else {
				state.groups = [first, ...state.groups];
			}
		}
	}, 2000);

	return state;
};

This should work for updating the values of individual options too

---

Groups do not appear for existing CLI sessions @mjbvz

Taking a look now. I think getChatSessionInputState being called is expected but I will confirm that we're passing over the right data