Improves default branch lookup

Author: eamodio

src/env/node/git/git.ts

@@ -1266,32 +1266,15 @@ export class Git {
 					return [ex.stdout, undefined];
 				}
 
+				let data;
 				try {
-					const data = await this.exec({ cwd: repoPath }, 'symbolic-ref', '--short', 'HEAD');
+					data = await this.exec({ cwd: repoPath }, 'symbolic-ref', '--short', 'HEAD');
 					if (data != null) return [data.trim(), undefined];
 				} catch {}
 
-				try {
-					const data = await this.exec(
-						{ cwd: repoPath },
-						'symbolic-ref',
-						'--short',
-						'refs/remotes/origin/HEAD',
-					);
-					if (data != null) return [data.trim().substring('origin/'.length), undefined];
-				} catch (ex) {
-					if (/is not a symbolic ref/.test(ex.stderr)) {
-						try {
-							const data = await this.exec({ cwd: repoPath }, 'ls-remote', '--symref', 'origin', 'HEAD');
-							if (data != null) {
-								const match = /ref:\s(\S+)\s+HEAD/m.exec(data);
-								if (match != null) {
-									const [, branch] = match;
-									return [branch.substring('refs/heads/'.length), undefined];
-								}
-							}
-						} catch {}
-					}
+				data = await this.symbolic_ref__HEAD(repoPath, 'origin');
+				if (data != null) {
+					return [data.startsWith('origin/') ? data.substring('origin/'.length) : data, undefined];
 				}
 
 				const defaultBranch = (await this.config__get('init.defaultBranch', repoPath)) ?? 'main';
@@ -1337,6 +1320,42 @@ export class Git {
 		}
 	}
 
+	async symbolic_ref__HEAD(repoPath: string, remote: string): Promise<string | undefined> {
+		let retried = false;
+		while (true) {
+			try {
+				const data = await this.exec(
+					{ cwd: repoPath },
+					'symbolic-ref',
+					'--short',
+					`refs/remotes/${remote}/HEAD`,
+				);
+				return data?.trim() || undefined;
+			} catch (ex) {
+				if (/is not a symbolic ref/.test(ex.stderr)) {
+					try {
+						if (!retried) {
+							retried = true;
+							await this.exec({ cwd: repoPath }, 'remote', 'set-head', '-a', remote);
+							continue;
+						}
+
+						const data = await this.exec({ cwd: repoPath }, 'ls-remote', '--symref', remote, 'HEAD');
+						if (data != null) {
+							const match = /ref:\s(\S+)\s+HEAD/m.exec(data);
+							if (match != null) {
+								const [, branch] = match;
+								return `${remote}/${branch.substring('refs/heads/'.length).trim()}`;
+							}
+						}
+					} catch {}
+				}
+
+				return undefined;
+			}
+		}
+	}
+
 	async rev_parse__git_dir(cwd: string): Promise<{ path: string; commonPath?: string } | undefined> {
 		const data = await this.exec(
 			{ cwd: cwd, errors: GitErrorHandling.Ignore },

src/env/node/git/sub-providers/branches.ts

@@ -375,25 +375,25 @@ export class BranchesGitSubProvider implements GitBranchesSubProvider {
 	async getDefaultBranchName(repoPath: string | undefined, remote?: string): Promise<string | undefined> {
 		if (repoPath == null) return undefined;
 
-		if (remote) {
-			try {
-				const data = await this.git.exec({ cwd: repoPath }, 'ls-remote', '--symref', remote, 'HEAD');
-				if (data == null) return undefined;
+		remote ??= 'origin';
 
-				const match = /ref:\s(\S+)\s+HEAD/m.exec(data);
-				if (match == null) return undefined;
+		const cacheByRemote = this.cache.defaultBranchName?.get(repoPath);
+		let promise = cacheByRemote?.get(remote);
+		if (promise == null) {
+			async function load(this: BranchesGitSubProvider): Promise<string | undefined> {
+				return this.git.symbolic_ref__HEAD(repoPath!, remote!);
+			}
 
-				const [, branch] = match;
-				return `${remote}/${branch.substring('refs/heads/'.length)}`;
-			} catch {}
-		}
+			promise = load.call(this);
 
-		try {
-			const data = await this.git.exec({ cwd: repoPath }, 'symbolic-ref', '--short', 'refs/remotes/origin/HEAD');
-			return data?.trim() || undefined;
-		} catch {}
+			if (cacheByRemote == null) {
+				this.cache.defaultBranchName?.set(repoPath, new Map([[remote, promise]]));
+			} else {
+				cacheByRemote.set(remote, promise);
+			}
+		}
 
-		return undefined;
+		return promise;
 	}
 
 	@log()

src/git/cache.ts

@@ -84,6 +84,13 @@ export class GitCache implements Disposable {
 			: undefined;
 	}
 
+	private _defaultBranchNameCache: Map<RepoPath, Map<string, Promise<string | undefined>>> | undefined;
+	get defaultBranchName(): Map<RepoPath, Map<string, Promise<string | undefined>>> | undefined {
+		return this.useCaching
+			? (this._defaultBranchNameCache ??= new Map<RepoPath, Map<string, Promise<string | undefined>>>())
+			: undefined;
+	}
+
 	private _pausedOperationStatusCache: Map<RepoPath, Promise<GitPausedOperationStatus | undefined>> | undefined;
 	get pausedOperationStatus(): Map<RepoPath, Promise<GitPausedOperationStatus | undefined>> | undefined {
 		return this.useCaching
@@ -128,6 +135,7 @@ export class GitCache implements Disposable {
 		if (!types.length || types.includes('branches')) {
 			cachesToClear.add(this._branchCache);
 			cachesToClear.add(this._branchesCache);
+			cachesToClear.add(this._defaultBranchNameCache);
 		}
 
 		if (!types.length || types.includes('contributors')) {
@@ -137,6 +145,7 @@ export class GitCache implements Disposable {
 		if (!types.length || types.includes('remotes')) {
 			cachesToClear.add(this._remotesCache);
 			cachesToClear.add(this._bestRemotesCache);
+			cachesToClear.add(this._defaultBranchNameCache);
 		}
 
 		if (!types.length || types.includes('providers')) {