Sessions - select the active branch in the branch picker (microsoft#296606)

* Git - observable repository state

* Wire-up the active branch selection

* Pull request feedback

Author: lszomoru

src/vs/sessions/contrib/chat/browser/branchPicker.ts

@@ -78,8 +78,9 @@ export class BranchPicker extends Disposable {
 			.filter((name): name is string => !!name)
 			.filter(name => !name.includes(COPILOT_WORKTREE_PATTERN));
 
-		// Select main, master, or the first branch by default
-		const defaultBranch = this._branches.find(b => b === 'main')
+		// Select active branch, main, master, or the first branch by default
+		const defaultBranch = this._branches.find(b => b === repository.state.get().HEAD?.name)
+			?? this._branches.find(b => b === 'main')
 			?? this._branches.find(b => b === 'master')
 			?? this._branches[0];
 		if (defaultBranch) {

src/vs/workbench/api/browser/mainThreadGitExtensionService.ts

@@ -97,7 +97,7 @@ export class MainThreadGitExtensionService extends Disposable implements MainThr
 
 			// Create a new repository and store it in the maps
 			const state = toGitRepositoryState(result.state);
-			const repository = new GitRepository(this, repositoryRootUri, state);
+			const repository = new GitRepository(repositoryRootUri, state, this);
 
 			this._repositories.set(result.handle, repository);
 			this._repositoryHandles.set(repositoryRootUri, result.handle);
@@ -135,6 +135,7 @@ export class MainThreadGitExtensionService extends Disposable implements MainThr
 			return;
 		}
 
-		repository.setState(toGitRepositoryState(state));
+		// Update the repository state
+		repository.updateState(toGitRepositoryState(state));
 	}
 }

src/vs/workbench/api/common/extHostGitExtensionService.ts

@@ -6,6 +6,7 @@
 import type * as vscode from 'vscode';
 import { Event } from '../../../base/common/event.js';
 import { Disposable, DisposableStore } from '../../../base/common/lifecycle.js';
+import { observableFromEvent, waitForState } from '../../../base/common/observable.js';
 import { URI, UriComponents } from '../../../base/common/uri.js';
 import { ExtensionIdentifier } from '../../../platform/extensions/common/extensions.js';
 import { createDecorator } from '../../../platform/instantiation/common/instantiation.js';
@@ -153,18 +154,20 @@ export class ExtHostGitExtensionService extends Disposable implements IExtHostGi
 			};
 		}
 
-		let repositoryState = repository.state;
-		if (repository.state.HEAD === undefined) {
-			// If the repository is not initialized, wait for it
-			await Event.toPromise(repository.state.onDidChange, this._disposables);
-			repositoryState = repository.state;
-		}
+		// Ensure that the repository state is initialized
+		const repositoryStateObs = observableFromEvent(this,
+			repository.state.onDidChange, () => repository.state);
+		await waitForState(repositoryStateObs, state => !!state.HEAD);
+
+		const repositoryState = repositoryStateObs.get();
 
+		// Store the repository and its handle in the maps
 		const handle = ExtHostGitExtensionService._handlePool++;
 
 		this._repositories.set(handle, repository);
 		this._repositoryByUri.set(repository.rootUri, handle);
 
+		// Subscribe to repository state changes
 		this._disposables.add(repository.state.onDidChange(() => {
 			this._proxy.$onDidChangeRepository(handle);
 		}));
@@ -173,7 +176,9 @@ export class ExtHostGitExtensionService extends Disposable implements IExtHostGi
 			handle,
 			rootUri: repository.rootUri,
 			state: {
-				HEAD: repositoryState.HEAD ? toGitBranchDto(repositoryState.HEAD) : undefined
+				HEAD: repositoryState.HEAD
+					? toGitBranchDto(repositoryState.HEAD)
+					: undefined
 			}
 		};
 	}

src/vs/workbench/contrib/git/browser/gitService.ts

@@ -4,11 +4,12 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { CancellationToken } from '../../../../base/common/cancellation.js';
-import { Emitter, Event } from '../../../../base/common/event.js';
 import { BugIndicatingError } from '../../../../base/common/errors.js';
 import { Disposable, IDisposable, toDisposable } from '../../../../base/common/lifecycle.js';
 import { URI } from '../../../../base/common/uri.js';
 import { IGitService, IGitExtensionDelegate, GitRef, GitRefQuery, IGitRepository, GitRepositoryState } from '../common/gitService.js';
+import { ISettableObservable, observableValueOpts } from '../../../../base/common/observable.js';
+import { structuralEquals } from '../../../../base/common/equals.js';
 
 export class GitService extends Disposable implements IGitService {
 	declare readonly _serviceBrand: undefined;
@@ -44,25 +45,22 @@ export class GitService extends Disposable implements IGitService {
 }
 
 export class GitRepository extends Disposable implements IGitRepository {
-	private readonly _onDidChangeState = this._register(new Emitter<void>());
-	readonly onDidChangeState: Event<void> = this._onDidChangeState.event;
+	readonly rootUri: URI;
 
-	private _state: GitRepositoryState;
-	get state(): GitRepositoryState { return this._state; }
-
-	setState(state: GitRepositoryState): void {
-		this._state = state;
-		this._onDidChangeState.fire();
+	readonly state: ISettableObservable<GitRepositoryState>;
+	updateState(state: GitRepositoryState): void {
+		this.state.set(state, undefined);
 	}
 
 	constructor(
-		private readonly delegate: IGitExtensionDelegate,
-		readonly rootUri: URI,
-		state: GitRepositoryState
+		rootUri: URI,
+		initialState: GitRepositoryState,
+		private readonly delegate: IGitExtensionDelegate
 	) {
 		super();
 
-		this._state = state;
+		this.rootUri = rootUri;
+		this.state = observableValueOpts({ owner: this, equalsFn: structuralEquals }, initialState);
 	}
 
 	async getRefs(query: GitRefQuery, token?: CancellationToken): Promise<GitRef[]> {

src/vs/workbench/contrib/git/common/gitService.ts

@@ -4,8 +4,8 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { CancellationToken } from '../../../../base/common/cancellation.js';
-import { Event } from '../../../../base/common/event.js';
 import { IDisposable } from '../../../../base/common/lifecycle.js';
+import { IObservable } from '../../../../base/common/observable.js';
 import { URI } from '../../../../base/common/uri.js';
 import { createDecorator } from '../../../../platform/instantiation/common/instantiation.js';
 
@@ -48,10 +48,8 @@ export interface GitUpstreamRef {
 export interface IGitRepository {
 	readonly rootUri: URI;
 
-	readonly state: GitRepositoryState;
-	setState(state: GitRepositoryState): void;
-
-	readonly onDidChangeState: Event<void>;
+	readonly state: IObservable<GitRepositoryState>;
+	updateState(state: GitRepositoryState): void;
 
 	getRefs(query: GitRefQuery, token?: CancellationToken): Promise<GitRef[]>;
 }