git.ts

/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { promises as fs, exists, realpath } from 'fs';
import * as path from 'path';
import * as os from 'os';
import * as cp from 'child_process';
import { fileURLToPath } from 'url';
import which from 'which';
import { EventEmitter } from 'events';
import * as iconv from '@vscode/iconv-lite-umd';
import * as filetype from 'file-type';
import { assign, groupBy, IDisposable, toDisposable, dispose, mkdirp, readBytes, detectUnicodeEncoding, Encoding, onceEvent, splitInChunks, Limiter, Versions, isWindows, pathEquals, isMacintosh, isDescendant } from './util';
import { CancellationError, CancellationToken, ConfigurationChangeEvent, LogOutputChannel, Progress, Uri, workspace } from 'vscode';
import { detectEncoding } from './encoding';
import { Ref, RefType, Branch, Remote, ForcePushMode, GitErrorCodes, LogOptions, Change, Status, CommitOptions, RefQuery, InitOptions } from './api/git';
import * as byline from 'byline';
import { StringDecoder } from 'string_decoder';

// https://github.com/microsoft/vscode/issues/65693
const MAX_CLI_LENGTH = 30000;

export interface IGit {
	path: string;
	version: string;
}

export interface IFileStatus {
	x: string;
	y: string;
	path: string;
	rename?: string;
}

export interface Stash {
	readonly hash: string;
	readonly parents: string[];
	readonly index: number;
	readonly description: string;
	readonly branchName?: string;
}

interface MutableRemote extends Remote {
	fetchUrl?: string;
	pushUrl?: string;
	isReadOnly: boolean;
}

// TODO@eamodio: Move to git.d.ts once we are good with the api
/**
 * Log file options.
 */
export interface LogFileOptions {
	/** Optional. Continue listing the history of a file beyond renames */
	readonly follow?: boolean;
	/** Optional. The maximum number of log entries to retrieve. */
	readonly maxEntries?: number | string;
	/** Optional. The Git sha (hash) to start retrieving log entries from. */
	readonly hash?: string;
	/** Optional. Specifies whether to start retrieving log entries in reverse order. */
	readonly reverse?: boolean;
	readonly sortByAuthorDate?: boolean;
	readonly shortStats?: boolean;
}

function parseVersion(raw: string): string {
	return raw.replace(/^git version /, '');
}

function findSpecificGit(path: string, onValidate: (path: string) => boolean): Promise<IGit> {
	return new Promise<IGit>((c, e) => {
		if (!onValidate(path)) {
			return e(new Error(`Path "${path}" is invalid.`));
		}

		const buffers: Buffer[] = [];
		const child = cp.spawn(path, ['--version']);
		child.stdout.on('data', (b: Buffer) => buffers.push(b));
		child.on('error', cpErrorHandler(e));
		child.on('close', code => code ? e(new Error(`Not found. Code: ${code}`)) : c({ path, version: parseVersion(Buffer.concat(buffers).toString('utf8').trim()) }));
	});
}

function findGitDarwin(onValidate: (path: string) => boolean): Promise<IGit> {
	return new Promise<IGit>((c, e) => {
		cp.exec('which git', (err, gitPathBuffer) => {
			if (err) {
				return e(new Error(`Executing "which git" failed: ${err.message}`));
			}

			const path = gitPathBuffer.toString().trim();

			function getVersion(path: string) {
				if (!onValidate(path)) {
					return e(new Error(`Path "${path}" is invalid.`));
				}

				// make sure git executes
				cp.exec('git --version', (err, stdout) => {

					if (err) {
						return e(new Error(`Executing "git --version" failed: ${err.message}`));
					}

					return c({ path, version: parseVersion(stdout.trim()) });
				});
			}

			if (path !== '/usr/bin/git') {
				return getVersion(path);
			}

			// must check if XCode is installed
			cp.exec('xcode-select -p', (err: any) => {
				if (err && err.code === 2) {
					// git is not installed, and launching /usr/bin/git
					// will prompt the user to install it

					return e(new Error('Executing "xcode-select -p" failed with error code 2.'));
				}

				getVersion(path);
			});
		});
	});
}

function findSystemGitWin32(base: string, onValidate: (path: string) => boolean): Promise<IGit> {
	if (!base) {
		return Promise.reject<IGit>('Not found');
	}

	return findSpecificGit(path.join(base, 'Git', 'cmd', 'git.exe'), onValidate);
}

async function findGitWin32InPath(onValidate: (path: string) => boolean): Promise<IGit> {
	const path = await which('git.exe');
	return findSpecificGit(path, onValidate);
}

function findGitWin32(onValidate: (path: string) => boolean): Promise<IGit> {
	return findSystemGitWin32(process.env['ProgramW6432'] as string, onValidate)
		.then(undefined, () => findSystemGitWin32(process.env['ProgramFiles(x86)'] as string, onValidate))
		.then(undefined, () => findSystemGitWin32(process.env['ProgramFiles'] as string, onValidate))
		.then(undefined, () => findSystemGitWin32(path.join(process.env['LocalAppData'] as string, 'Programs'), onValidate))
		.then(undefined, () => findGitWin32InPath(onValidate));
}

export async function findGit(hints: string[], onValidate: (path: string) => boolean, logger: LogOutputChannel): Promise<IGit> {
	for (const hint of hints) {
		try {
			return await findSpecificGit(hint, onValidate);
		} catch (err) {
			// noop
			logger.info(`Unable to find git on the PATH: "${hint}". Error: ${err.message}`);
		}
	}

	try {
		switch (process.platform) {
			case 'darwin': return await findGitDarwin(onValidate);
			case 'win32': return await findGitWin32(onValidate);
			default: return await findSpecificGit('git', onValidate);
		}
	} catch (err) {
		// noop
		logger.warn(`Unable to find git. Error: ${err.message}`);
	}

	throw new Error('Git installation not found.');
}

export interface IExecutionResult<T extends string | Buffer> {
	exitCode: number;
	stdout: T;
	stderr: string;
}

function cpErrorHandler(cb: (reason?: any) => void): (reason?: any) => void {
	return err => {
		if (/ENOENT/.test(err.message)) {
			err = new GitError({
				error: err,
				message: 'Failed to execute git (ENOENT)',
				gitErrorCode: GitErrorCodes.NotAGitRepository
			});
		}

		cb(err);
	};
}

export interface SpawnOptions extends cp.SpawnOptions {
	input?: string;
	encoding?: string;
	log?: boolean;
	cancellationToken?: CancellationToken;
	onSpawn?: (childProcess: cp.ChildProcess) => void;
}

async function exec(child: cp.ChildProcess, cancellationToken?: CancellationToken): Promise<IExecutionResult<Buffer>> {
	if (!child.stdout || !child.stderr) {
		throw new GitError({ message: 'Failed to get stdout or stderr from git process.' });
	}

	if (cancellationToken && cancellationToken.isCancellationRequested) {
		throw new CancellationError();
	}

	const disposables: IDisposable[] = [];

	const once = (ee: NodeJS.EventEmitter, name: string, fn: (...args: any[]) => void) => {
		ee.once(name, fn);
		disposables.push(toDisposable(() => ee.removeListener(name, fn)));
	};

	const on = (ee: NodeJS.EventEmitter, name: string, fn: (...args: any[]) => void) => {
		ee.on(name, fn);
		disposables.push(toDisposable(() => ee.removeListener(name, fn)));
	};

	let result = Promise.all<any>([
		new Promise<number>((c, e) => {
			once(child, 'error', cpErrorHandler(e));
			once(child, 'exit', c);
		}),
		new Promise<Buffer>(c => {
			const buffers: Buffer[] = [];
			on(child.stdout!, 'data', (b: Buffer) => buffers.push(b));
			once(child.stdout!, 'close', () => c(Buffer.concat(buffers)));
		}),
		new Promise<string>(c => {
			const buffers: Buffer[] = [];
			on(child.stderr!, 'data', (b: Buffer) => buffers.push(b));
			once(child.stderr!, 'close', () => c(Buffer.concat(buffers).toString('utf8')));
		})
	]) as Promise<[number, Buffer, string]>;

	if (cancellationToken) {
		const cancellationPromise = new Promise<[number, Buffer, string]>((_, e) => {
			onceEvent(cancellationToken.onCancellationRequested)(() => {
				try {
					child.kill();
				} catch (err) {
					// noop
				}

				e(new CancellationError());
			});
		});

		result = Promise.race([result, cancellationPromise]);
	}

	try {
		const [exitCode, stdout, stderr] = await result;
		return { exitCode, stdout, stderr };
	} finally {
		dispose(disposables);
	}
}

export interface IGitErrorData {
	error?: Error;
	message?: string;
	stdout?: string;
	stderr?: string;
	exitCode?: number;
	gitErrorCode?: string;
	gitCommand?: string;
	gitArgs?: string[];
}

export class GitError extends Error {

	error?: Error;
	stdout?: string;
	stderr?: string;
	exitCode?: number;
	gitErrorCode?: string;
	gitCommand?: string;
	gitArgs?: string[];

	constructor(data: IGitErrorData) {
		super(data.error?.message || data.message || 'Git error');

		this.error = data.error;
		this.stdout = data.stdout;
		this.stderr = data.stderr;
		this.exitCode = data.exitCode;
		this.gitErrorCode = data.gitErrorCode;
		this.gitCommand = data.gitCommand;
		this.gitArgs = data.gitArgs;
	}

	override toString(): string {
		let result = this.message + ' ' + JSON.stringify({
			exitCode: this.exitCode,
			gitErrorCode: this.gitErrorCode,
			gitCommand: this.gitCommand,
			stdout: this.stdout,
			stderr: this.stderr
		}, null, 2);

		if (this.error) {
			result += (<any>this.error).stack;
		}

		return result;
	}
}

export interface IGitOptions {
	gitPath: string;
	userAgent: string;
	version: string;
	env?: { [key: string]: string };
}

function getGitErrorCode(stderr: string): string | undefined {
	if (/Another git process seems to be running in this repository|If no other git process is currently running/.test(stderr)) {
		return GitErrorCodes.RepositoryIsLocked;
	} else if (/Authentication failed/i.test(stderr)) {
		return GitErrorCodes.AuthenticationFailed;
	} else if (/Not a git repository/i.test(stderr)) {
		return GitErrorCodes.NotAGitRepository;
	} else if (/bad config file/.test(stderr)) {
		return GitErrorCodes.BadConfigFile;
	} else if (/cannot make pipe for command substitution|cannot create standard input pipe/.test(stderr)) {
		return GitErrorCodes.CantCreatePipe;
	} else if (/Repository not found/.test(stderr)) {
		return GitErrorCodes.RepositoryNotFound;
	} else if (/unable to access/.test(stderr)) {
		return GitErrorCodes.CantAccessRemote;
	} else if (/branch '.+' is not fully merged/.test(stderr)) {
		return GitErrorCodes.BranchNotFullyMerged;
	} else if (/Couldn\'t find remote ref/.test(stderr)) {
		return GitErrorCodes.NoRemoteReference;
	} else if (/A branch named '.+' already exists/.test(stderr)) {
		return GitErrorCodes.BranchAlreadyExists;
	} else if (/'.+' is not a valid branch name/.test(stderr)) {
		return GitErrorCodes.InvalidBranchName;
	} else if (/Please,? commit your changes or stash them/.test(stderr)) {
		return GitErrorCodes.DirtyWorkTree;
	}

	return undefined;
}

// https://github.com/microsoft/vscode/issues/89373
// https://github.com/git-for-windows/git/issues/2478
function sanitizePath(path: string): string {
	return path.replace(/^([a-z]):\\/i, (_, letter) => `${letter.toUpperCase()}:\\`);
}

const COMMIT_FORMAT = '%H%n%aN%n%aE%n%at%n%ct%n%P%n%D%n%B';
const STASH_FORMAT = '%H%n%P%n%gd%n%gs';

export interface ICloneOptions {
	readonly parentPath: string;
	readonly progress: Progress<{ increment: number }>;
	readonly recursive?: boolean;
	readonly ref?: string;
}

export class Git {

	readonly path: string;
	readonly userAgent: string;
	readonly version: string;
	readonly env: { [key: string]: string };

	private commandsToLog: string[] = [];

	private _onOutput = new EventEmitter();
	get onOutput(): EventEmitter { return this._onOutput; }

	constructor(options: IGitOptions) {
		this.path = options.gitPath;
		this.version = options.version;
		this.userAgent = options.userAgent;
		this.env = options.env || {};

		const onConfigurationChanged = (e?: ConfigurationChangeEvent) => {
			if (e !== undefined && !e.affectsConfiguration('git.commandsToLog')) {
				return;
			}

			const config = workspace.getConfiguration('git');
			this.commandsToLog = config.get<string[]>('commandsToLog', []);
		};

		workspace.onDidChangeConfiguration(onConfigurationChanged, this);
		onConfigurationChanged();
	}

	compareGitVersionTo(version: string): -1 | 0 | 1 {
		return Versions.compare(Versions.fromString(this.version), Versions.fromString(version));
	}

	open(repositoryRoot: string, repositoryRootRealPath: string | undefined, dotGit: { path: string; commonPath?: string }, logger: LogOutputChannel): Repository {
		return new Repository(this, repositoryRoot, repositoryRootRealPath, dotGit, logger);
	}

	async init(repository: string, options: InitOptions = {}): Promise<void> {
		const args = ['init'];

		if (options.defaultBranch && options.defaultBranch !== '' && this.compareGitVersionTo('2.28.0') !== -1) {
			args.push('-b', options.defaultBranch);
		}

		await this.exec(repository, args);
	}

	async clone(url: string, options: ICloneOptions, cancellationToken?: CancellationToken): Promise<string> {
		const baseFolderName = decodeURI(url).replace(/[\/]+$/, '').replace(/^.*[\/\\]/, '').replace(/\.git$/, '') || 'repository';
		let folderName = baseFolderName;
		let folderPath = path.join(options.parentPath, folderName);
		let count = 1;

		while (count < 20 && await new Promise(c => exists(folderPath, c))) {
			folderName = `${baseFolderName}-${count++}`;
			folderPath = path.join(options.parentPath, folderName);
		}

		await mkdirp(options.parentPath);

		const onSpawn = (child: cp.ChildProcess) => {
			const decoder = new StringDecoder('utf8');
			const lineStream = new byline.LineStream({ encoding: 'utf8' });
			child.stderr!.on('data', (buffer: Buffer) => lineStream.write(decoder.write(buffer)));

			let totalProgress = 0;
			let previousProgress = 0;

			lineStream.on('data', (line: string) => {
				let match: RegExpExecArray | null = null;

				if (match = /Counting objects:\s*(\d+)%/i.exec(line)) {
					totalProgress = Math.floor(parseInt(match[1]) * 0.1);
				} else if (match = /Compressing objects:\s*(\d+)%/i.exec(line)) {
					totalProgress = 10 + Math.floor(parseInt(match[1]) * 0.1);
				} else if (match = /Receiving objects:\s*(\d+)%/i.exec(line)) {
					totalProgress = 20 + Math.floor(parseInt(match[1]) * 0.4);
				} else if (match = /Resolving deltas:\s*(\d+)%/i.exec(line)) {
					totalProgress = 60 + Math.floor(parseInt(match[1]) * 0.4);
				}

				if (totalProgress !== previousProgress) {
					options.progress.report({ increment: totalProgress - previousProgress });
					previousProgress = totalProgress;
				}
			});
		};

		try {
			const command = ['clone', url.includes(' ') ? encodeURI(url) : url, folderPath, '--progress'];
			if (options.recursive) {
				command.push('--recursive');
			}
			if (options.ref) {
				command.push('--branch', options.ref);
			}
			await this.exec(options.parentPath, command, {
				cancellationToken,
				env: { 'GIT_HTTP_USER_AGENT': this.userAgent },
				onSpawn,
			});
		} catch (err) {
			if (err.stderr) {
				err.stderr = err.stderr.replace(/^Cloning.+$/m, '').trim();
				err.stderr = err.stderr.replace(/^ERROR:\s+/, '').trim();
			}

			throw err;
		}

		return folderPath;
	}

	async getRepositoryRoot(pathInsidePossibleRepository: string): Promise<string> {
		const result = await this.exec(pathInsidePossibleRepository, ['rev-parse', '--show-toplevel']);

		// Keep trailing spaces which are part of the directory name
		const repositoryRootPath = path.normalize(result.stdout.trimStart().replace(/[\r\n]+$/, ''));

		// Handle symbolic links and UNC paths
		// Git 2.31 added the `--path-format` flag to rev-parse which
		// allows us to get the relative path of the repository root
		if (!pathEquals(pathInsidePossibleRepository, repositoryRootPath) &&
			!isDescendant(repositoryRootPath, pathInsidePossibleRepository) &&
			!isDescendant(pathInsidePossibleRepository, repositoryRootPath) &&
			this.compareGitVersionTo('2.31.0') !== -1) {
			const relativePathResult = await this.exec(pathInsidePossibleRepository, ['rev-parse', '--path-format=relative', '--show-toplevel',]);
			return path.resolve(pathInsidePossibleRepository, relativePathResult.stdout.trimStart().replace(/[\r\n]+$/, ''));
		}

		if (isWindows) {
			// On Git 2.25+ if you call `rev-parse --show-toplevel` on a mapped drive, instead of getting the mapped
			// drive path back, you get the UNC path for the mapped drive. So we will try to normalize it back to the
			// mapped drive path, if possible
			const repoUri = Uri.file(repositoryRootPath);
			const pathUri = Uri.file(pathInsidePossibleRepository);
			if (repoUri.authority.length !== 0 && pathUri.authority.length === 0) {
				const match = /^[\/]?([a-zA-Z])[:\/]/.exec(pathUri.path);
				if (match !== null) {
					const [, letter] = match;

					try {
						const networkPath = await new Promise<string | undefined>(resolve =>
							realpath.native(`${letter}:\\`, { encoding: 'utf8' }, (err, resolvedPath) =>
								resolve(err !== null ? undefined : resolvedPath),
							),
						);
						if (networkPath !== undefined) {
							// If the repository is at the root of the mapped drive then we
							// have to append `\` (ex: D:\) otherwise the path is not valid.
							const isDriveRoot = pathEquals(repoUri.fsPath, networkPath);

							return path.normalize(
								repoUri.fsPath.replace(
									networkPath,
									`${letter.toLowerCase()}:${isDriveRoot || networkPath.endsWith('\\') ? '\\' : ''}`
								),
							);
						}
					} catch { }
				}

				return path.normalize(pathUri.fsPath);
			}
		}

		return repositoryRootPath;
	}

	async getRepositoryDotGit(repositoryPath: string): Promise<{ path: string; commonPath?: string }> {
		const result = await this.exec(repositoryPath, ['rev-parse', '--git-dir', '--git-common-dir']);
		let [dotGitPath, commonDotGitPath] = result.stdout.split('\n').map(r => r.trim());

		if (!path.isAbsolute(dotGitPath)) {
			dotGitPath = path.join(repositoryPath, dotGitPath);
		}
		dotGitPath = path.normalize(dotGitPath);

		if (commonDotGitPath) {
			if (!path.isAbsolute(commonDotGitPath)) {
				commonDotGitPath = path.join(repositoryPath, commonDotGitPath);
			}
			commonDotGitPath = path.normalize(commonDotGitPath);

			return { path: dotGitPath, commonPath: commonDotGitPath !== dotGitPath ? commonDotGitPath : undefined };
		}

		return { path: dotGitPath };
	}

	async exec(cwd: string, args: string[], options: SpawnOptions = {}): Promise<IExecutionResult<string>> {
		options = assign({ cwd }, options || {});
		return await this._exec(args, options);
	}

	async exec2(args: string[], options: SpawnOptions = {}): Promise<IExecutionResult<string>> {
		return await this._exec(args, options);
	}

	stream(cwd: string, args: string[], options: SpawnOptions = {}): cp.ChildProcess {
		options = assign({ cwd }, options || {});
		const child = this.spawn(args, options);

		if (options.log !== false) {
			const startTime = Date.now();
			child.on('exit', (_) => {
				this.log(`> git ${args.join(' ')} [${Date.now() - startTime}ms]${child.killed ? ' (cancelled)' : ''}\n`);
			});
		}

		return child;
	}

	private async _exec(args: string[], options: SpawnOptions = {}): Promise<IExecutionResult<string>> {
		const child = this.spawn(args, options);

		options.onSpawn?.(child);

		if (options.input) {
			child.stdin!.end(options.input, 'utf8');
		}

		const startExec = Date.now();
		let bufferResult: IExecutionResult<Buffer>;

		try {
			bufferResult = await exec(child, options.cancellationToken);
		} catch (ex) {
			if (ex instanceof CancellationError) {
				this.log(`> git ${args.join(' ')} [${Date.now() - startExec}ms] (cancelled)\n`);
			}

			throw ex;
		}

		if (options.log !== false) {
			// command
			this.log(`> git ${args.join(' ')} [${Date.now() - startExec}ms]\n`);

			// stdout
			if (bufferResult.stdout.length > 0 && args.find(a => this.commandsToLog.includes(a))) {
				this.log(`${bufferResult.stdout}\n`);
			}

			// stderr
			if (bufferResult.stderr.length > 0) {
				this.log(`${bufferResult.stderr}\n`);
			}
		}

		let encoding = options.encoding || 'utf8';
		encoding = iconv.encodingExists(encoding) ? encoding : 'utf8';

		const result: IExecutionResult<string> = {
			exitCode: bufferResult.exitCode,
			stdout: iconv.decode(bufferResult.stdout, encoding),
			stderr: bufferResult.stderr
		};

		if (bufferResult.exitCode) {
			return Promise.reject<IExecutionResult<string>>(new GitError({
				message: 'Failed to execute git',
				stdout: result.stdout,
				stderr: result.stderr,
				exitCode: result.exitCode,
				gitErrorCode: getGitErrorCode(result.stderr),
				gitCommand: args[0],
				gitArgs: args
			}));
		}

		return result;
	}

	spawn(args: string[], options: SpawnOptions = {}): cp.ChildProcess {
		if (!this.path) {
			throw new Error('git could not be found in the system.');
		}

		if (!options) {
			options = {};
		}

		if (!options.stdio && !options.input) {
			options.stdio = ['ignore', null, null]; // Unless provided, ignore stdin and leave default streams for stdout and stderr
		}

		options.env = assign({}, process.env, this.env, options.env || {}, {
			VSCODE_GIT_COMMAND: args[0],
			LC_ALL: 'en_US.UTF-8',
			LANG: 'en_US.UTF-8',
			GIT_PAGER: 'cat'
		});

		const cwd = this.getCwd(options);
		if (cwd) {
			options.cwd = sanitizePath(cwd);
		}

		return cp.spawn(this.path, args, options);
	}

	private getCwd(options: SpawnOptions): string | undefined {
		const cwd = options.cwd;
		if (typeof cwd === 'undefined' || typeof cwd === 'string') {
			return cwd;
		}

		if (cwd.protocol === 'file:') {
			return fileURLToPath(cwd);
		}

		return undefined;
	}

	private log(output: string): void {
		this._onOutput.emit('log', output);
	}

	async mergeFile(options: { input1Path: string; input2Path: string; basePath: string; diff3?: boolean }): Promise<string> {
		const args = ['merge-file', '-p', options.input1Path, options.basePath, options.input2Path];
		if (options.diff3) {
			args.push('--diff3');
		} else {
			args.push('--no-diff3');
		}

		try {
			const result = await this.exec(os.homedir(), args);
			return result.stdout;
		} catch (err) {
			if (typeof err.stdout === 'string') {
				// The merge had conflicts, stdout still contains the merged result (with conflict markers)
				return err.stdout;
			} else {
				throw err;
			}
		}
	}

	async addSafeDirectory(repositoryPath: string): Promise<void> {
		await this.exec(os.homedir(), ['config', '--global', '--add', 'safe.directory', repositoryPath]);
		return;
	}
}

export interface CommitShortStat {
	readonly files: number;
	readonly insertions: number;
	readonly deletions: number;
}

export interface Commit {
	hash: string;
	message: string;
	parents: string[];
	authorDate?: Date;
	authorName?: string;
	authorEmail?: string;
	commitDate?: Date;
	refNames: string[];
	shortStat?: CommitShortStat;
}

interface GitConfigSection {
	name: string;
	subSectionName?: string;
	properties: { [key: string]: string };
}

class GitConfigParser {
	private static readonly _lineSeparator = /\r?\n/;

	private static readonly _propertyRegex = /^\s*(\w+)\s*=\s*"?([^"]+)"?$/;
	private static readonly _sectionRegex = /^\s*\[\s*([^\]]+?)\s*(\"[^"]+\")*\]\s*$/;

	static parse(raw: string): GitConfigSection[] {
		const config: { sections: GitConfigSection[] } = { sections: [] };
		let section: GitConfigSection = { name: 'DEFAULT', properties: {} };

		const addSection = (section?: GitConfigSection) => {
			if (!section) { return; }
			config.sections.push(section);
		};

		for (const line of raw.split(GitConfigParser._lineSeparator)) {
			// Section
			const sectionMatch = line.match(GitConfigParser._sectionRegex);
			if (sectionMatch?.length === 3) {
				addSection(section);
				section = { name: sectionMatch[1], subSectionName: sectionMatch[2]?.replaceAll('"', ''), properties: {} };

				continue;
			}

			// Property
			const propertyMatch = line.match(GitConfigParser._propertyRegex);
			if (propertyMatch?.length === 3 && !Object.keys(section.properties).includes(propertyMatch[1])) {
				section.properties[propertyMatch[1]] = propertyMatch[2];
			}
		}

		addSection(section);

		return config.sections;
	}
}

export class GitStatusParser {

	private lastRaw = '';
	private result: IFileStatus[] = [];

	get status(): IFileStatus[] {
		return this.result;
	}

	update(raw: string): void {
		let i = 0;
		let nextI: number | undefined;

		raw = this.lastRaw + raw;

		while ((nextI = this.parseEntry(raw, i)) !== undefined) {
			i = nextI;
		}

		this.lastRaw = raw.substr(i);
	}

	private parseEntry(raw: string, i: number): number | undefined {
		if (i + 4 >= raw.length) {
			return;
		}

		let lastIndex: number;
		const entry: IFileStatus = {
			x: raw.charAt(i++),
			y: raw.charAt(i++),
			rename: undefined,
			path: ''
		};

		// space
		i++;

		if (entry.x === 'R' || entry.y === 'R' || entry.x === 'C') {
			lastIndex = raw.indexOf('\0', i);

			if (lastIndex === -1) {
				return;
			}

			entry.rename = raw.substring(i, lastIndex);
			i = lastIndex + 1;
		}

		lastIndex = raw.indexOf('\0', i);

		if (lastIndex === -1) {
			return;
		}

		entry.path = raw.substring(i, lastIndex);

		// If path ends with slash, it must be a nested git repo
		if (entry.path[entry.path.length - 1] !== '/') {
			this.result.push(entry);
		}

		return lastIndex + 1;
	}
}

export interface Submodule {
	name: string;
	path: string;
	url: string;
}

export function parseGitmodules(raw: string): Submodule[] {
	const result: Submodule[] = [];

	for (const submoduleSection of GitConfigParser.parse(raw).filter(s => s.name === 'submodule')) {
		if (submoduleSection.subSectionName && submoduleSection.properties['path'] && submoduleSection.properties['url']) {
			result.push({
				name: submoduleSection.subSectionName,
				path: submoduleSection.properties['path'],
				url: submoduleSection.properties['url']
			});
		}
	}

	return result;
}

export function parseGitRemotes(raw: string): MutableRemote[] {
	const remotes: MutableRemote[] = [];

	for (const remoteSection of GitConfigParser.parse(raw).filter(s => s.name === 'remote')) {
		if (remoteSection.subSectionName) {
			remotes.push({
				name: remoteSection.subSectionName,
				fetchUrl: remoteSection.properties['url'],
				pushUrl: remoteSection.properties['pushurl'] ?? remoteSection.properties['url'],
				isReadOnly: false
			});
		}
	}

	return remotes;
}

const commitRegex = /([0-9a-f]{40})\n(.*)\n(.*)\n(.*)\n(.*)\n(.*)\n(.*)(?:\n([^]*?))?(?:\x00)(?:\n((?:.*)files? changed(?:.*))$)?/gm;

export function parseGitCommits(data: string): Commit[] {
	const commits: Commit[] = [];

	let ref;
	let authorName;
	let authorEmail;
	let authorDate;
	let commitDate;
	let parents;
	let refNames;
	let message;
	let shortStat;
	let match;

	do {
		match = commitRegex.exec(data);
		if (match === null) {
			break;
		}

		[, ref, authorName, authorEmail, authorDate, commitDate, parents, refNames, message, shortStat] = match;

		if (message[message.length - 1] === '\n') {
			message = message.substr(0, message.length - 1);
		}

		// Stop excessive memory usage by using substr -- https://bugs.chromium.org/p/v8/issues/detail?id=2869
		commits.push({
			hash: ` ${ref}`.substr(1),
			message: ` ${message}`.substr(1),
			parents: parents ? parents.split(' ') : [],
			authorDate: new Date(Number(authorDate) * 1000),
			authorName: ` ${authorName}`.substr(1),
			authorEmail: ` ${authorEmail}`.substr(1),
			commitDate: new Date(Number(commitDate) * 1000),
			refNames: refNames.split(',').map(s => s.trim()),
			shortStat: shortStat ? parseGitDiffShortStat(shortStat) : undefined
		});
	} while (true);

	return commits;
}

const diffShortStatRegex = /(\d+) files? changed(?:, (\d+) insertions?\(\+\))?(?:, (\d+) deletions?\(-\))?/;

function parseGitDiffShortStat(data: string): CommitShortStat {
	const matches = data.trim().match(diffShortStatRegex);

	if (!matches) {
		return { files: 0, insertions: 0, deletions: 0 };
	}

	const [, files, insertions = undefined, deletions = undefined] = matches;
	return { files: parseInt(files), insertions: parseInt(insertions ?? '0'), deletions: parseInt(deletions ?? '0') };
}

export interface LsTreeElement {
	mode: string;
	type: string;
	object: string;
	size: string;
	file: string;
}

export function parseLsTree(raw: string): LsTreeElement[] {
	return raw.split('\n')
		.filter(l => !!l)
		.map(line => /^(\S+)\s+(\S+)\s+(\S+)\s+(\S+)\s+(.*)$/.exec(line)!)
		.filter(m => !!m)
		.map(([, mode, type, object, size, file]) => ({ mode, type, object, size, file }));
}

interface LsFilesElement {
	mode: string;
	object: string;
	stage: string;
	file: string;
}

export function parseLsFiles(raw: string): LsFilesElement[] {
	return raw.split('\n')
		.filter(l => !!l)
		.map(line => /^(\S+)\s+(\S+)\s+(\S+)\s+(.*)$/.exec(line)!)
		.filter(m => !!m)
		.map(([, mode, object, stage, file]) => ({ mode, object, stage, file }));
}

const stashRegex = /([0-9a-f]{40})\n(.*)\nstash@{(\d+)}\n(WIP\s)*on([^:]+):(.*)(?:\x00)/gmi;

function parseGitStashes(raw: string): Stash[] {
	const result: Stash[] = [];

	let match, hash, parents, index, wip, branchName, description;

	do {
		match = stashRegex.exec(raw);
		if (match === null) {
			break;
		}

		[, hash, parents, index, wip, branchName, description] = match;
		result.push({
			hash,
			parents: parents.split(' '),
			index: parseInt(index),
			branchName: branchName.trim(),
			description: wip ? `WIP (${description.trim()})` : description.trim()
		});
	} while (true);

	return result;
}

function parseGitChanges(repositoryRoot: string, raw: string): Change[] {
	let index = 0;
	const result: Change[] = [];
	const segments = raw.trim().split('\x00').filter(s => s);

	segmentsLoop:
	while (index < segments.length - 1) {
		const change = segments[index++];
		const resourcePath = segments[index++];

		if (!change || !resourcePath) {
			break;
		}

		const originalUri = Uri.file(path.isAbsolute(resourcePath) ? resourcePath : path.join(repositoryRoot, resourcePath));

		let uri = originalUri;
		let renameUri = originalUri;
		let status = Status.UNTRACKED;

		// Copy or Rename status comes with a number (ex: 'R100').
		// We don't need the number, we use only first character of the status.
		switch (change[0]) {
			case 'A':
				status = Status.INDEX_ADDED;
				break;

			case 'M':
				status = Status.MODIFIED;
				break;

			case 'D':
				status = Status.DELETED;
				break;

			// Rename contains two paths, the second one is what the file is renamed/copied to.
			case 'R': {
				if (index >= segments.length) {
					break;
				}

				const newPath = segments[index++];
				if (!newPath) {
					break;
				}

				status = Status.INDEX_RENAMED;
				uri = renameUri = Uri.file(path.isAbsolute(newPath) ? newPath : path.join(repositoryRoot, newPath));
				break;
			}
			default:
				// Unknown status
				break segmentsLoop;
		}

		result.push({ status, uri, originalUri, renameUri });
	}

	return result;
}

export interface BlameInformation {
	readonly hash: string;
	readonly subject?: string;
	readonly authorName?: string;
	readonly authorEmail?: string;
	readonly authorDate?: number;
	readonly ranges: {
		readonly startLineNumber: number;
		readonly endLineNumber: number;
	}[];
}

function parseGitBlame(data: string): BlameInformation[] {
	const lineSeparator = /\r?\n/;
	const commitRegex = /^([0-9a-f]{40})/gm;

	const blameInformation = new Map<string, BlameInformation>();

	let commitHash: string | undefined = undefined;
	let authorName: string | undefined = undefined;
	let authorEmail: string | undefined = undefined;
	let authorTime: number | undefined = undefined;
	let message: string | undefined = undefined;
	let startLineNumber: number | undefined = undefined;
	let endLineNumber: number | undefined = undefined;

	for (const line of data.split(lineSeparator)) {
		// Commit
		const commitMatch = line.match(commitRegex);
		if (!commitHash && commitMatch) {
			const segments = line.split(' ');

			commitHash = commitMatch[0];
			startLineNumber = Number(segments[2]);
			endLineNumber = Number(segments[2]) + Number(segments[3]) - 1;
		}

		// Commit properties
		if (commitHash && line.startsWith('author ')) {
			authorName = line.substring('author '.length);
		}
		if (commitHash && line.startsWith('author-mail ')) {
			authorEmail = line.substring('author-mail <'.length, line.length - 1);
		}
		if (commitHash && line.startsWith('author-time ')) {
			authorTime = Number(line.substring('author-time '.length)) * 1000;
		}
		if (commitHash && line.startsWith('summary ')) {
			message = line.substring('summary '.length);
		}

		// Commit end
		if (commitHash && startLineNumber && endLineNumber && line.startsWith('filename ')) {
			const existingCommit = blameInformation.get(commitHash);
			if (existingCommit) {
				existingCommit.ranges.push({ startLineNumber, endLineNumber });
				blameInformation.set(commitHash, existingCommit);
			} else {
				blameInformation.set(commitHash, {
					hash: commitHash, authorName, authorEmail, authorDate: authorTime, subject: message, ranges: [{ startLineNumber, endLineNumber }]
				});
			}

			commitHash = authorName = authorEmail = authorTime = message = startLineNumber = endLineNumber = undefined;
		}
	}

	return Array.from(blameInformation.values());
}

export interface PullOptions {
	unshallow?: boolean;
	tags?: boolean;
	readonly cancellationToken?: CancellationToken;
}

export class Repository {
	private _isUsingRefTable = false;

	constructor(
		private _git: Git,
		private repositoryRoot: string,
		private repositoryRootRealPath: string | undefined,
		readonly dotGit: { path: string; commonPath?: string },
		private logger: LogOutputChannel
	) { }

	get git(): Git {
		return this._git;
	}

	get root(): string {
		return this.repositoryRoot;
	}

	get rootRealPath(): string | undefined {
		return this.repositoryRootRealPath;
	}

	async exec(args: string[], options: SpawnOptions = {}): Promise<IExecutionResult<string>> {
		return await this.git.exec(this.repositoryRoot, args, options);
	}

	stream(args: string[], options: SpawnOptions = {}): cp.ChildProcess {
		return this.git.stream(this.repositoryRoot, args, options);
	}

	spawn(args: string[], options: SpawnOptions = {}): cp.ChildProcess {
		return this.git.spawn(args, options);
	}

	async config(command: string, scope: string, key: string, value: any = null, options: SpawnOptions = {}): Promise<string> {
		const args = ['config', `--${command}`];

		if (scope) {
			args.push(`--${scope}`);
		}

		args.push(key);

		if (value) {
			args.push(value);
		}

		try {
			const result = await this.exec(args, options);
			return result.stdout.trim();
		}
		catch (err) {
			this.logger.warn(`[Git][config] git config failed: ${err.message}`);
			return '';
		}
	}

	async getConfigs(scope: string): Promise<{ key: string; value: string }[]> {
		const args = ['config'];

		if (scope) {
			args.push('--' + scope);
		}

		args.push('-l');

		const result = await this.exec(args);
		const lines = result.stdout.trim().split(/\r|\r\n|\n/);

		return lines.map(entry => {
			const equalsIndex = entry.indexOf('=');
			return { key: entry.substr(0, equalsIndex), value: entry.substr(equalsIndex + 1) };
		});
	}

	async log(options?: LogOptions): Promise<Commit[]> {
		const spawnOptions: SpawnOptions = {};
		const args = ['log', `--format=${COMMIT_FORMAT}`, '-z'];

		if (options?.shortStats) {
			args.push('--shortstat');

			if (this._git.compareGitVersionTo('2.31') !== -1) {
				args.push('--diff-merges=first-parent');
			}
		}

		if (options?.reverse) {
			args.push('--reverse', '--ancestry-path');
		}

		if (options?.sortByAuthorDate) {
			args.push('--author-date-order');
		}

		if (options?.range) {
			args.push(options.range);
		} else {
			args.push(`-n${options?.maxEntries ?? 32}`);
		}

		if (options?.author) {
			args.push(`--author="${options.author}"`);
		}

		if (typeof options?.maxParents === 'number') {
			args.push(`--max-parents=${options.maxParents}`);
		}

		if (typeof options?.skip === 'number') {
			args.push(`--skip=${options.skip}`);
		}

		if (options?.refNames) {
			args.push('--topo-order');
			args.push('--decorate=full');

			// In order to avoid hitting the command line limit due to large number of reference
			// names (can happen when the `all` filter is used in the Source Control Graph view),
			// we are passing the reference names via stdin.
			spawnOptions.input = options.refNames.join('\n');
			args.push('--stdin');
		}

		if (options?.path) {
			args.push('--', options.path);
		}

		const result = await this.exec(args, spawnOptions);
		if (result.exitCode) {
			// An empty repo
			return [];
		}

		return parseGitCommits(result.stdout);
	}

	async logFile(uri: Uri, options?: LogFileOptions): Promise<Commit[]> {
		const args = ['log', `--format=${COMMIT_FORMAT}`, '-z'];

		if (options?.maxEntries && !options?.reverse) {
			args.push(`-n${options.maxEntries}`);
		}

		if (options?.hash) {
			// If we are reversing, we must add a range (with HEAD) because we are using --ancestry-path for better reverse walking
			if (options?.reverse) {
				args.push('--reverse', '--ancestry-path', `${options.hash}..HEAD`);
			} else {
				args.push(options.hash);
			}
		}

		if (options?.shortStats) {
			args.push('--shortstat');
		}

		if (options?.sortByAuthorDate) {
			args.push('--author-date-order');
		}

		if (options?.follow) {
			args.push('--follow');
		}

		args.push('--', uri.fsPath);

		try {
			const result = await this.exec(args);
			if (result.exitCode) {
				// No file history, e.g. a new file or untracked
				return [];
			}

			return parseGitCommits(result.stdout);
		} catch (err) {
			// Repository has no commits yet
			if (/does not have any commits yet/.test(err.stderr)) {
				return [];
			}

			throw err;
		}
	}

	async reflog(ref: string, pattern: string): Promise<string[]> {
		const args = ['reflog', ref, `--grep-reflog=${pattern}`];
		const result = await this.exec(args);
		if (result.exitCode) {
			return [];
		}

		return result.stdout.split('\n')
			.filter(entry => !!entry);
	}

	async bufferString(object: string, encoding: string = 'utf8', autoGuessEncoding = false, candidateGuessEncodings: string[] = []): Promise<string> {
		const stdout = await this.buffer(object);

		if (autoGuessEncoding) {
			encoding = detectEncoding(stdout, candidateGuessEncodings) || encoding;
		}

		encoding = iconv.encodingExists(encoding) ? encoding : 'utf8';

		return iconv.decode(stdout, encoding);
	}

	async buffer(object: string): Promise<Buffer> {
		const child = this.stream(['show', '--textconv', object]);

		if (!child.stdout) {
			return Promise.reject<Buffer>('Can\'t open file from git');
		}

		const { exitCode, stdout, stderr } = await exec(child);

		if (exitCode) {
			const err = new GitError({
				message: 'Could not show object.',
				exitCode
			});

			if (/exists on disk, but not in/.test(stderr)) {
				err.gitErrorCode = GitErrorCodes.WrongCase;
			}

			return Promise.reject<Buffer>(err);
		}

		return stdout;
	}

	async getObjectDetails(treeish: string, path: string): Promise<{ mode: string; object: string; size: number }> {
		if (!treeish || treeish === ':1' || treeish === ':2' || treeish === ':3') { // index
			const elements = await this.lsfiles(path);

			if (elements.length === 0) {
				throw new GitError({ message: 'Path not known by git', gitErrorCode: GitErrorCodes.UnknownPath });
			}

			const { mode, object } = treeish !== ''
				? elements.find(e => e.stage === treeish.substring(1)) ?? elements[0]
				: elements[0];

			const catFile = await this.exec(['cat-file', '-s', object]);
			const size = parseInt(catFile.stdout);

			return { mode, object, size };
		}

		const elements = await this.lstree(treeish, path);

		if (elements.length === 0) {
			throw new GitError({ message: 'Path not known by git', gitErrorCode: GitErrorCodes.UnknownPath });
		}

		const { mode, object, size } = elements[0];
		return { mode, object, size: parseInt(size) };
	}

	async lstree(treeish: string, path?: string): Promise<LsTreeElement[]> {
		const args = ['ls-tree', '-l', treeish];
		if (path) {
			args.push('--', sanitizePath(path));
		}

		const { stdout } = await this.exec(args);
		return parseLsTree(stdout);
	}

	async lsfiles(path: string): Promise<LsFilesElement[]> {
		const { stdout } = await this.exec(['ls-files', '--stage', '--', sanitizePath(path)]);
		return parseLsFiles(stdout);
	}

	async getGitRelativePath(ref: string, relativePath: string): Promise<string> {
		const relativePathLowercase = relativePath.toLowerCase();
		const dirname = path.posix.dirname(relativePath) + '/';
		const elements: { file: string }[] = ref ? await this.lstree(ref, dirname) : await this.lsfiles(dirname);
		const element = elements.filter(file => file.file.toLowerCase() === relativePathLowercase)[0];

		if (!element) {
			throw new GitError({
				message: `Git relative path not found. Was looking for ${relativePathLowercase} among ${JSON.stringify(elements.map(({ file }) => file), null, 2)}`,
			});
		}

		return element.file;
	}

	async detectObjectType(object: string): Promise<{ mimetype: string; encoding?: string }> {
		const child = await this.stream(['show', '--textconv', object]);
		const buffer = await readBytes(child.stdout!, 4100);

		try {
			child.kill();
		} catch (err) {
			// noop
		}

		const encoding = detectUnicodeEncoding(buffer);
		let isText = true;

		if (encoding !== Encoding.UTF16be && encoding !== Encoding.UTF16le) {
			for (let i = 0; i < buffer.length; i++) {
				if (buffer.readInt8(i) === 0) {
					isText = false;
					break;
				}
			}
		}

		if (!isText) {
			const result = await filetype.fromBuffer(buffer);

			if (!result) {
				return { mimetype: 'application/octet-stream' };
			} else {
				return { mimetype: result.mime };
			}
		}

		if (encoding) {
			return { mimetype: 'text/plain', encoding };
		} else {
			// TODO@JOAO: read the setting OUTSIDE!
			return { mimetype: 'text/plain' };
		}
	}

	async apply(patch: string, reverse?: boolean): Promise<void> {
		const args = ['apply', patch];

		if (reverse) {
			args.push('-R');
		}

		try {
			await this.exec(args);
		} catch (err) {
			if (/patch does not apply/.test(err.stderr)) {
				err.gitErrorCode = GitErrorCodes.PatchDoesNotApply;
			}

			throw err;
		}
	}

	async diff(cached = false): Promise<string> {
		const args = ['diff'];

		if (cached) {
			args.push('--cached');
		}

		const result = await this.exec(args);
		return result.stdout;
	}

	diffWithHEAD(): Promise<Change[]>;
	diffWithHEAD(path: string): Promise<string>;
	diffWithHEAD(path?: string | undefined): Promise<string | Change[]>;
	async diffWithHEAD(path?: string | undefined): Promise<string | Change[]> {
		if (!path) {
			return await this.diffFiles(false);
		}

		const args = ['diff', '--', sanitizePath(path)];
		const result = await this.exec(args);
		return result.stdout;
	}

	diffWith(ref: string): Promise<Change[]>;
	diffWith(ref: string, path: string): Promise<string>;
	diffWith(ref: string, path?: string | undefined): Promise<string | Change[]>;
	async diffWith(ref: string, path?: string): Promise<string | Change[]> {
		if (!path) {
			return await this.diffFiles(false, ref);
		}

		const args = ['diff', ref, '--', sanitizePath(path)];
		const result = await this.exec(args);
		return result.stdout;
	}

	diffIndexWithHEAD(): Promise<Change[]>;
	diffIndexWithHEAD(path: string): Promise<string>;
	diffIndexWithHEAD(path?: string | undefined): Promise<Change[]>;
	async diffIndexWithHEAD(path?: string): Promise<string | Change[]> {
		if (!path) {
			return await this.diffFiles(true);
		}

		const args = ['diff', '--cached', '--', sanitizePath(path)];
		const result = await this.exec(args);
		return result.stdout;
	}

	diffIndexWith(ref: string): Promise<Change[]>;
	diffIndexWith(ref: string, path: string): Promise<string>;
	diffIndexWith(ref: string, path?: string | undefined): Promise<string | Change[]>;
	async diffIndexWith(ref: string, path?: string): Promise<string | Change[]> {
		if (!path) {
			return await this.diffFiles(true, ref);
		}

		const args = ['diff', '--cached', ref, '--', sanitizePath(path)];
		const result = await this.exec(args);
		return result.stdout;
	}

	async diffBlobs(object1: string, object2: string): Promise<string> {
		const args = ['diff', object1, object2];
		const result = await this.exec(args);
		return result.stdout;
	}

	diffBetween(ref1: string, ref2: string): Promise<Change[]>;
	diffBetween(ref1: string, ref2: string, path: string): Promise<string>;
	diffBetween(ref1: string, ref2: string, path?: string | undefined): Promise<string | Change[]>;
	async diffBetween(ref1: string, ref2: string, path?: string): Promise<string | Change[]> {
		const range = `${ref1}...${ref2}`;
		if (!path) {
			return await this.diffFiles(false, range);
		}

		const args = ['diff', range, '--', sanitizePath(path)];
		const result = await this.exec(args);

		return result.stdout.trim();
	}

	async diffBetweenShortStat(ref1: string, ref2: string): Promise<{ files: number; insertions: number; deletions: number }> {
		const args = ['diff', '--shortstat', `${ref1}...${ref2}`];

		const result = await this.exec(args);
		if (result.exitCode) {
			return { files: 0, insertions: 0, deletions: 0 };
		}

		return parseGitDiffShortStat(result.stdout.trim());
	}

	private async diffFiles(cached: boolean, ref?: string): Promise<Change[]> {
		const args = ['diff', '--name-status', '-z', '--diff-filter=ADMR'];
		if (cached) {
			args.push('--cached');
		}

		if (ref) {
			args.push(ref);
		}

		const gitResult = await this.exec(args);
		if (gitResult.exitCode) {
			return [];
		}

		return parseGitChanges(this.repositoryRoot, gitResult.stdout);
	}

	async diffTrees(treeish1: string, treeish2?: string, options?: { similarityThreshold?: number }): Promise<Change[]> {
		const args = ['diff-tree', '-r', '--name-status', '-z', '--diff-filter=ADMR'];

		if (options?.similarityThreshold) {
			args.push(`--find-renames=${options.similarityThreshold}%`);
		}

		args.push(treeish1);

		if (treeish2) {
			args.push(treeish2);
		}

		const gitResult = await this.exec(args);
		if (gitResult.exitCode) {
			return [];
		}

		return parseGitChanges(this.repositoryRoot, gitResult.stdout);
	}

	async getMergeBase(ref1: string, ref2: string, ...refs: string[]): Promise<string | undefined> {
		try {
			const args = ['merge-base'];
			if (refs.length !== 0) {
				args.push('--octopus');
				args.push(...refs);
			}

			args.push(ref1, ref2);

			const result = await this.exec(args);

			return result.stdout.trim();
		}
		catch (err) {
			return undefined;
		}
	}

	async hashObject(data: string): Promise<string> {
		const args = ['hash-object', '-w', '--stdin'];
		const result = await this.exec(args, { input: data });

		return result.stdout.trim();
	}

	async add(paths: string[], opts?: { update?: boolean }): Promise<void> {
		const args = ['add'];

		if (opts && opts.update) {
			args.push('-u');
		} else {
			args.push('-A');
		}

		if (paths && paths.length) {
			for (const chunk of splitInChunks(paths.map(sanitizePath), MAX_CLI_LENGTH)) {
				await this.exec([...args, '--', ...chunk]);
			}
		} else {
			await this.exec([...args, '--', '.']);
		}
	}

	async rm(paths: string[]): Promise<void> {
		const args = ['rm', '--'];

		if (!paths || !paths.length) {
			return;
		}

		args.push(...paths.map(sanitizePath));

		await this.exec(args);
	}

	async stage(path: string, data: string, encoding: string): Promise<void> {
		const child = this.stream(['hash-object', '--stdin', '-w', '--path', sanitizePath(path)], { stdio: [null, null, null] });
		child.stdin!.end(iconv.encode(data, encoding));

		const { exitCode, stdout } = await exec(child);
		const hash = stdout.toString('utf8');

		if (exitCode) {
			throw new GitError({
				message: 'Could not hash object.',
				exitCode: exitCode
			});
		}

		const treeish = await this.getCommit('HEAD').then(() => 'HEAD', () => '');
		let mode: string;
		let add: string = '';

		try {
			const details = await this.getObjectDetails(treeish, path);
			mode = details.mode;
		} catch (err) {
			if (err.gitErrorCode !== GitErrorCodes.UnknownPath) {
				throw err;
			}

			mode = '100644';
			add = '--add';
		}

		await this.exec(['update-index', add, '--cacheinfo', mode, hash, path]);
	}

	async checkout(treeish: string, paths: string[], opts: { track?: boolean; detached?: boolean } = Object.create(null)): Promise<void> {
		const args = ['checkout', '-q'];

		if (opts.track) {
			args.push('--track');
		}

		if (opts.detached) {
			args.push('--detach');
		}

		if (treeish) {
			args.push(treeish);
		}

		try {
			if (paths && paths.length > 0) {
				for (const chunk of splitInChunks(paths.map(sanitizePath), MAX_CLI_LENGTH)) {
					await this.exec([...args, '--', ...chunk]);
				}
			} else {
				await this.exec(args);
			}
		} catch (err) {
			if (/Please,? commit your changes or stash them/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.DirtyWorkTree;
				err.gitTreeish = treeish;
			} else if (/You are on a branch yet to be born/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.BranchNotYetBorn;
			}

			throw err;
		}
	}

	async commit(message: string | undefined, opts: CommitOptions = Object.create(null)): Promise<void> {
		const args = ['commit', '--quiet'];
		const options: SpawnOptions = {};

		if (message) {
			options.input = message;
			args.push('--allow-empty-message', '--file', '-');
		}

		if (opts.verbose) {
			args.push('--verbose');
		}

		if (opts.all) {
			args.push('--all');
		}

		if (opts.amend) {
			args.push('--amend');
		}

		if (!opts.useEditor) {
			if (!message) {
				if (opts.amend) {
					args.push('--no-edit');
				} else {
					options.input = '';
					args.push('--file', '-');
				}
			}

			args.push('--allow-empty-message');
		}

		if (opts.signoff) {
			args.push('--signoff');
		}

		if (opts.signCommit) {
			args.push('-S');
		}

		if (opts.empty) {
			args.push('--allow-empty');
		}

		if (opts.noVerify) {
			args.push('--no-verify');
		}

		if (opts.requireUserConfig ?? true) {
			// Stops git from guessing at user/email
			args.splice(0, 0, '-c', 'user.useConfigOnly=true');
		}

		try {
			await this.exec(args, options);
		} catch (commitErr) {
			await this.handleCommitError(commitErr);
		}
	}

	async rebaseAbort(): Promise<void> {
		await this.exec(['rebase', '--abort']);
	}

	async rebaseContinue(): Promise<void> {
		const args = ['rebase', '--continue'];

		try {
			await this.exec(args, { env: { GIT_EDITOR: 'true' } });
		} catch (commitErr) {
			await this.handleCommitError(commitErr);
		}
	}

	private async handleCommitError(commitErr: any): Promise<void> {
		if (/not possible because you have unmerged files/.test(commitErr.stderr || '')) {
			commitErr.gitErrorCode = GitErrorCodes.UnmergedChanges;
			throw commitErr;
		} else if (/Aborting commit due to empty commit message/.test(commitErr.stderr || '')) {
			commitErr.gitErrorCode = GitErrorCodes.EmptyCommitMessage;
			throw commitErr;
		}

		try {
			await this.exec(['config', '--get-all', 'user.name']);
		} catch (err) {
			err.gitErrorCode = GitErrorCodes.NoUserNameConfigured;
			throw err;
		}

		try {
			await this.exec(['config', '--get-all', 'user.email']);
		} catch (err) {
			err.gitErrorCode = GitErrorCodes.NoUserEmailConfigured;
			throw err;
		}

		throw commitErr;
	}

	async branch(name: string, checkout: boolean, ref?: string): Promise<void> {
		const args = checkout ? ['checkout', '-q', '-b', name, '--no-track'] : ['branch', '-q', name];

		if (ref) {
			args.push(ref);
		}

		await this.exec(args);
	}

	async deleteBranch(name: string, force?: boolean): Promise<void> {
		const args = ['branch', force ? '-D' : '-d', name];
		await this.exec(args);
	}

	async renameBranch(name: string): Promise<void> {
		const args = ['branch', '-m', name];
		await this.exec(args);
	}

	async move(from: string, to: string): Promise<void> {
		const args = ['mv', from, to];
		await this.exec(args);
	}

	async setBranchUpstream(name: string, upstream: string): Promise<void> {
		const args = ['branch', '--set-upstream-to', upstream, name];
		await this.exec(args);
	}

	async deleteRef(ref: string): Promise<void> {
		const args = ['update-ref', '-d', ref];
		await this.exec(args);
	}

	async merge(ref: string): Promise<void> {
		const args = ['merge', ref];

		try {
			await this.exec(args);
		} catch (err) {
			if (/^CONFLICT /m.test(err.stdout || '')) {
				err.gitErrorCode = GitErrorCodes.Conflict;
			}

			throw err;
		}
	}

	async mergeAbort(): Promise<void> {
		await this.exec(['merge', '--abort']);
	}

	async mergeContinue(): Promise<void> {
		const args = ['merge', '--continue'];

		try {
			await this.exec(args, { env: { GIT_EDITOR: 'true' } });
		} catch (commitErr) {
			await this.handleCommitError(commitErr);
		}
	}

	async tag(options: { name: string; message?: string; ref?: string }): Promise<void> {
		let args = ['tag'];

		if (options.message) {
			args = [...args, '-a', options.name, '-m', options.message];
		} else {
			args = [...args, options.name];
		}

		if (options.ref) {
			args.push(options.ref);
		}

		await this.exec(args);
	}

	async deleteTag(name: string): Promise<void> {
		const args = ['tag', '-d', name];
		await this.exec(args);
	}

	async deleteRemoteTag(remoteName: string, tagName: string): Promise<void> {
		const args = ['push', '--delete', remoteName, tagName];
		await this.exec(args);
	}

	async clean(paths: string[]): Promise<void> {
		const pathsByGroup = groupBy(paths.map(sanitizePath), p => path.dirname(p));
		const groups = Object.keys(pathsByGroup).map(k => pathsByGroup[k]);

		const limiter = new Limiter(5);
		const promises: Promise<any>[] = [];
		const args = ['clean', '-f', '-q'];

		for (const paths of groups) {
			for (const chunk of splitInChunks(paths.map(sanitizePath), MAX_CLI_LENGTH)) {
				promises.push(limiter.queue(() => this.exec([...args, '--', ...chunk])));
			}
		}

		await Promise.all(promises);
	}

	async undo(): Promise<void> {
		await this.exec(['clean', '-fd']);

		try {
			await this.exec(['checkout', '--', '.']);
		} catch (err) {
			if (/did not match any file\(s\) known to git\./.test(err.stderr || '')) {
				return;
			}

			throw err;
		}
	}

	async reset(treeish: string, hard: boolean = false): Promise<void> {
		const args = ['reset', hard ? '--hard' : '--soft', treeish];
		await this.exec(args);
	}

	async revert(treeish: string, paths: string[]): Promise<void> {
		const result = await this.exec(['branch']);
		let args: string[];

		// In case there are no branches, we must use rm --cached
		if (!result.stdout) {
			args = ['rm', '--cached', '-r'];
		} else {
			args = ['reset', '-q', treeish];
		}

		try {
			if (paths && paths.length > 0) {
				for (const chunk of splitInChunks(paths.map(sanitizePath), MAX_CLI_LENGTH)) {
					await this.exec([...args, '--', ...chunk]);
				}
			} else {
				await this.exec([...args, '--', '.']);
			}
		} catch (err) {
			// In case there are merge conflicts to be resolved, git reset will output
			// some "needs merge" data. We try to get around that.
			if (/([^:]+: needs merge\n)+/m.test(err.stdout || '')) {
				return;
			}

			throw err;
		}
	}

	async addRemote(name: string, url: string): Promise<void> {
		const args = ['remote', 'add', name, url];
		await this.exec(args);
	}

	async removeRemote(name: string): Promise<void> {
		const args = ['remote', 'remove', name];
		await this.exec(args);
	}

	async renameRemote(name: string, newName: string): Promise<void> {
		const args = ['remote', 'rename', name, newName];
		await this.exec(args);
	}

	async fetch(options: { remote?: string; ref?: string; all?: boolean; prune?: boolean; depth?: number; silent?: boolean; readonly cancellationToken?: CancellationToken } = {}): Promise<void> {
		const args = ['fetch'];
		const spawnOptions: SpawnOptions = {
			cancellationToken: options.cancellationToken,
			env: { 'GIT_HTTP_USER_AGENT': this.git.userAgent }
		};

		if (options.remote) {
			args.push(options.remote);

			if (options.ref) {
				args.push(options.ref);
			}
		} else if (options.all) {
			args.push('--all');
		}

		if (options.prune) {
			args.push('--prune');
		}

		if (typeof options.depth === 'number') {
			args.push(`--depth=${options.depth}`);
		}

		if (options.silent) {
			spawnOptions.env!['VSCODE_GIT_FETCH_SILENT'] = 'true';
		}

		try {
			await this.exec(args, spawnOptions);
		} catch (err) {
			if (/No remote repository specified\./.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.NoRemoteRepositorySpecified;
			} else if (/Could not read from remote repository/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.RemoteConnectionError;
			} else if (/! \[rejected\].*\(non-fast-forward\)/m.test(err.stderr || '')) {
				// The local branch has outgoing changes and it cannot be fast-forwarded.
				err.gitErrorCode = GitErrorCodes.BranchFastForwardRejected;
			}

			throw err;
		}
	}

	async fetchTags(options: { remote: string; tags: string[]; force?: boolean }): Promise<void> {
		const args = ['fetch'];
		const spawnOptions: SpawnOptions = {
			env: { 'GIT_HTTP_USER_AGENT': this.git.userAgent }
		};

		args.push(options.remote);

		for (const tag of options.tags) {
			args.push(`refs/tags/${tag}:refs/tags/${tag}`);
		}

		if (options.force) {
			args.push('--force');
		}

		await this.exec(args, spawnOptions);
	}

	async pull(rebase?: boolean, remote?: string, branch?: string, options: PullOptions = {}): Promise<void> {
		const args = ['pull'];

		if (options.tags) {
			args.push('--tags');
		}

		if (options.unshallow) {
			args.push('--unshallow');
		}

		if (rebase) {
			args.push('-r');
		}

		if (remote && branch) {
			args.push(remote);
			args.push(branch);
		}

		try {
			await this.exec(args, {
				cancellationToken: options.cancellationToken,
				env: { 'GIT_HTTP_USER_AGENT': this.git.userAgent }
			});
		} catch (err) {
			if (/^CONFLICT \([^)]+\): \b/m.test(err.stdout || '')) {
				err.gitErrorCode = GitErrorCodes.Conflict;
			} else if (/Please tell me who you are\./.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.NoUserNameConfigured;
			} else if (/Could not read from remote repository/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.RemoteConnectionError;
			} else if (/Pull(?:ing)? is not possible because you have unmerged files|Cannot pull with rebase: You have unstaged changes|Your local changes to the following files would be overwritten|Please, commit your changes before you can merge/i.test(err.stderr)) {
				err.stderr = err.stderr.replace(/Cannot pull with rebase: You have unstaged changes/i, 'Cannot pull with rebase, you have unstaged changes');
				err.gitErrorCode = GitErrorCodes.DirtyWorkTree;
			} else if (/cannot lock ref|unable to update local ref/i.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.CantLockRef;
			} else if (/cannot rebase onto multiple branches/i.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.CantRebaseMultipleBranches;
			} else if (/! \[rejected\].*\(would clobber existing tag\)/m.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.TagConflict;
			}

			throw err;
		}
	}

	async rebase(branch: string, options: PullOptions = {}): Promise<void> {
		const args = ['rebase'];

		args.push(branch);

		try {
			await this.exec(args, options);
		} catch (err) {
			if (/^CONFLICT \([^)]+\): \b/m.test(err.stdout || '')) {
				err.gitErrorCode = GitErrorCodes.Conflict;
			} else if (/cannot rebase onto multiple branches/i.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.CantRebaseMultipleBranches;
			}

			throw err;
		}
	}

	async push(remote?: string, name?: string, setUpstream: boolean = false, followTags = false, forcePushMode?: ForcePushMode, tags = false): Promise<void> {
		const args = ['push'];

		if (forcePushMode === ForcePushMode.ForceWithLease || forcePushMode === ForcePushMode.ForceWithLeaseIfIncludes) {
			args.push('--force-with-lease');
			if (forcePushMode === ForcePushMode.ForceWithLeaseIfIncludes && this._git.compareGitVersionTo('2.30') !== -1) {
				args.push('--force-if-includes');
			}
		} else if (forcePushMode === ForcePushMode.Force) {
			args.push('--force');
		}

		if (setUpstream) {
			args.push('-u');
		}

		if (followTags) {
			args.push('--follow-tags');
		}

		if (tags) {
			args.push('--tags');
		}

		if (remote) {
			args.push(remote);
		}

		if (name) {
			args.push(name);
		}

		try {
			await this.exec(args, { env: { 'GIT_HTTP_USER_AGENT': this.git.userAgent } });
		} catch (err) {
			if (/^error: failed to push some refs to\b/m.test(err.stderr || '')) {
				if (forcePushMode === ForcePushMode.ForceWithLease && /! \[rejected\].*\(stale info\)/m.test(err.stderr || '')) {
					err.gitErrorCode = GitErrorCodes.ForcePushWithLeaseRejected;
				} else if (forcePushMode === ForcePushMode.ForceWithLeaseIfIncludes && /! \[rejected\].*\(remote ref updated since checkout\)/m.test(err.stderr || '')) {
					err.gitErrorCode = GitErrorCodes.ForcePushWithLeaseIfIncludesRejected;
				} else {
					err.gitErrorCode = GitErrorCodes.PushRejected;
				}
			} else if (/Permission.*denied/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.PermissionDenied;
			} else if (/Could not read from remote repository/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.RemoteConnectionError;
			} else if (/^fatal: The current branch .* has no upstream branch/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.NoUpstreamBranch;
			}

			throw err;
		}
	}

	async cherryPick(commitHash: string): Promise<void> {
		try {
			await this.exec(['cherry-pick', commitHash]);
		} catch (err) {
			if (/The previous cherry-pick is now empty, possibly due to conflict resolution./.test(err.stderr ?? '')) {
				// Abort cherry-pick
				await this.cherryPickAbort();

				err.gitErrorCode = GitErrorCodes.CherryPickEmpty;
			} else {
				// Conflict during cherry-pick
				err.gitErrorCode = GitErrorCodes.CherryPickConflict;
			}

			throw err;
		}
	}

	async cherryPickAbort(): Promise<void> {
		await this.exec(['cherry-pick', '--abort']);
	}

	async blame(path: string): Promise<string> {
		try {
			const args = ['blame', sanitizePath(path)];
			const result = await this.exec(args);
			return result.stdout.trim();
		} catch (err) {
			if (/^fatal: no such path/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.NoPathFound;
			}

			throw err;
		}
	}

	async blame2(path: string, ref?: string): Promise<BlameInformation[] | undefined> {
		try {
			const args = ['blame', '--root', '--incremental'];

			if (ref) {
				args.push(ref);
			}

			args.push('--', sanitizePath(path));

			const result = await this.exec(args);

			return parseGitBlame(result.stdout.trim());
		}
		catch (err) {
			return undefined;
		}
	}

	async createStash(message?: string, includeUntracked?: boolean, staged?: boolean): Promise<void> {
		try {
			const args = ['stash', 'push'];

			if (includeUntracked) {
				args.push('-u');
			}

			if (staged) {
				args.push('-S');
			}

			if (message) {
				args.push('-m', message);
			}

			await this.exec(args);
		} catch (err) {
			if (/No local changes to save/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.NoLocalChanges;
			}

			throw err;
		}
	}

	async popStash(index?: number): Promise<void> {
		const args = ['stash', 'pop'];
		await this.popOrApplyStash(args, index);
	}

	async applyStash(index?: number): Promise<void> {
		const args = ['stash', 'apply'];
		await this.popOrApplyStash(args, index);
	}

	private async popOrApplyStash(args: string[], index?: number): Promise<void> {
		try {
			if (typeof index === 'number') {
				args.push(`stash@{${index}}`);
			}

			await this.exec(args);
		} catch (err) {
			if (/No stash found/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.NoStashFound;
			} else if (/error: Your local changes to the following files would be overwritten/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.LocalChangesOverwritten;
			} else if (/^CONFLICT/m.test(err.stdout || '')) {
				err.gitErrorCode = GitErrorCodes.StashConflict;
			}

			throw err;
		}
	}

	async dropStash(index?: number): Promise<void> {
		const args = ['stash'];

		if (typeof index === 'number') {
			args.push('drop');
			args.push(`stash@{${index}}`);
		} else {
			args.push('clear');
		}

		try {
			await this.exec(args);
		} catch (err) {
			if (/No stash found/.test(err.stderr || '')) {
				err.gitErrorCode = GitErrorCodes.NoStashFound;
			}

			throw err;
		}
	}

	async showStash(index: number): Promise<Change[] | undefined> {
		const args = ['stash', 'show', `stash@{${index}}`, '--name-status', '-z', '-u'];

		try {
			const result = await this.exec(args);
			if (result.exitCode) {
				return [];
			}

			return parseGitChanges(this.repositoryRoot, result.stdout.trim());
		} catch (err) {
			if (/No stash found/.test(err.stderr || '')) {
				return undefined;
			}

			throw err;
		}
	}

	async getStatus(opts?: { limit?: number; ignoreSubmodules?: boolean; similarityThreshold?: number; untrackedChanges?: 'mixed' | 'separate' | 'hidden'; cancellationToken?: CancellationToken }): Promise<{ status: IFileStatus[]; statusLength: number; didHitLimit: boolean }> {
		if (opts?.cancellationToken && opts?.cancellationToken.isCancellationRequested) {
			throw new CancellationError();
		}

		const disposables: IDisposable[] = [];

		const env = { GIT_OPTIONAL_LOCKS: '0' };
		const args = ['status', '-z'];

		if (opts?.untrackedChanges === 'hidden') {
			args.push('-uno');
		} else {
			args.push('-uall');
		}

		if (opts?.ignoreSubmodules) {
			args.push('--ignore-submodules');
		}

		// --find-renames option is only available starting with git 2.18.0
		if (opts?.similarityThreshold && opts.similarityThreshold !== 50 && this._git.compareGitVersionTo('2.18.0') !== -1) {
			args.push(`--find-renames=${opts.similarityThreshold}%`);
		}

		const child = this.stream(args, { env });

		let result = new Promise<{ status: IFileStatus[]; statusLength: number; didHitLimit: boolean }>((c, e) => {
			const parser = new GitStatusParser();

			const onClose = (exitCode: number) => {
				if (exitCode !== 0) {
					const stderr = stderrData.join('');
					return e(new GitError({
						message: 'Failed to execute git',
						stderr,
						exitCode,
						gitErrorCode: getGitErrorCode(stderr),
						gitCommand: 'status',
						gitArgs: args
					}));
				}

				c({ status: parser.status, statusLength: parser.status.length, didHitLimit: false });
			};

			const limit = opts?.limit ?? 10000;
			const onStdoutData = (raw: string) => {
				parser.update(raw);

				if (limit !== 0 && parser.status.length > limit) {
					child.removeListener('close', onClose);
					child.stdout!.removeListener('data', onStdoutData);
					child.kill();

					c({ status: parser.status.slice(0, limit), statusLength: parser.status.length, didHitLimit: true });
				}
			};

			child.stdout!.setEncoding('utf8');
			child.stdout!.on('data', onStdoutData);

			const stderrData: string[] = [];
			child.stderr!.setEncoding('utf8');
			child.stderr!.on('data', raw => stderrData.push(raw as string));

			child.on('error', cpErrorHandler(e));
			child.on('close', onClose);
		});

		if (opts?.cancellationToken) {
			const cancellationPromise = new Promise<{ status: IFileStatus[]; statusLength: number; didHitLimit: boolean }>((_, e) => {
				disposables.push(onceEvent(opts.cancellationToken!.onCancellationRequested)(() => {
					try {
						child.kill();
					} catch (err) {
						// noop
					}

					e(new CancellationError());
				}));
			});

			result = Promise.race([result, cancellationPromise]);
		}

		try {
			const { status, statusLength, didHitLimit } = await result;
			return { status, statusLength, didHitLimit };
		}
		finally {
			dispose(disposables);
		}
	}

	async getHEADRef(): Promise<Branch | undefined> {
		let HEAD: Branch | undefined;

		try {
			HEAD = await this.getHEAD();

			if (HEAD.name) {
				// Branch
				HEAD = await this.getBranch(HEAD.name);

				// Upstream commit
				if (HEAD && HEAD.upstream) {
					const ref = HEAD.upstream.remote !== '.'
						? `refs/remotes/${HEAD.upstream.remote}/${HEAD.upstream.name}`
						: `refs/heads/${HEAD.upstream.name}`;
					const commit = await this.revParse(ref);
					HEAD = { ...HEAD, upstream: { ...HEAD.upstream, commit } };
				}
			} else if (HEAD.commit) {
				// Tag || Commit
				const tags = await this.getRefs({ pattern: 'refs/tags' });
				const tag = tags.find(tag => tag.commit === HEAD!.commit);

				if (tag) {
					HEAD = { ...HEAD, name: tag.name, type: RefType.Tag };
				}
			}
		} catch (err) {
			// noop
		}

		return HEAD;
	}

	async getHEAD(): Promise<Ref> {
		if (!this._isUsingRefTable) {
			try {
				// Attempt to parse the HEAD file
				const result = await this.getHEADFS();

				// Git 2.45 adds support for a new reference storage backend called "reftable", promising
				// faster lookups, reads, and writes for repositories with any number of references. For
				// backwards compatibility the `.git/HEAD` file contains `ref: refs/heads/.invalid`. More
				// details are available at https://git-scm.com/docs/reftable
				if (result.name === '.invalid') {
					this._isUsingRefTable = true;
					this.logger.warn(`[Git][getHEAD] Failed to parse HEAD file: Repository is using reftable format.`);
				} else {
					return result;
				}
			}
			catch (err) {
				this.logger.warn(`[Git][getHEAD] Failed to parse HEAD file: ${err.message}`);
			}
		}

		try {
			// Fallback to using git to determine HEAD
			const result = await this.exec(['symbolic-ref', '--short', 'HEAD']);

			if (!result.stdout) {
				throw new Error('Not in a branch');
			}

			return { name: result.stdout.trim(), commit: undefined, type: RefType.Head };
		}
		catch (err) { }

		// Detached HEAD
		const result = await this.exec(['rev-parse', 'HEAD']);

		if (!result.stdout) {
			throw new Error('Error parsing HEAD');
		}

		return { name: undefined, commit: result.stdout.trim(), type: RefType.Head };
	}

	async getHEADFS(): Promise<Ref> {
		const raw = await fs.readFile(path.join(this.dotGit.path, 'HEAD'), 'utf8');

		// Branch
		const branchMatch = raw.match(/^ref: refs\/heads\/(?<name>.*)$/m);
		if (branchMatch?.groups?.name) {
			return { name: branchMatch.groups.name, commit: undefined, type: RefType.Head };
		}

		// Detached
		const commitMatch = raw.match(/^(?<commit>[0-9a-f]{40})$/m);
		if (commitMatch?.groups?.commit) {
			return { name: undefined, commit: commitMatch.groups.commit, type: RefType.Head };
		}

		throw new Error(`Unable to parse HEAD file. HEAD file contents: ${raw}.`);
	}

	async findTrackingBranches(upstreamBranch: string): Promise<Branch[]> {
		const result = await this.exec(['for-each-ref', '--format', '%(refname:short)%00%(upstream:short)', 'refs/heads']);
		return result.stdout.trim().split('\n')
			.map(line => line.trim().split('\0'))
			.filter(([_, upstream]) => upstream === upstreamBranch)
			.map(([ref]): Branch => ({ name: ref, type: RefType.Head }));
	}

	async getRefs(query: RefQuery, cancellationToken?: CancellationToken): Promise<Ref[]> {
		if (cancellationToken && cancellationToken.isCancellationRequested) {
			throw new CancellationError();
		}

		const args = ['for-each-ref'];

		if (query.count) {
			args.push(`--count=${query.count}`);
		}

		if (query.sort && query.sort !== 'alphabetically') {
			args.push('--sort', `-${query.sort}`);
		}

		args.push('--format', '%(refname) %(objectname) %(*objectname)');

		if (query.pattern) {
			const patterns = Array.isArray(query.pattern) ? query.pattern : [query.pattern];
			for (const pattern of patterns) {
				args.push(pattern.startsWith('refs/') ? pattern : `refs/${pattern}`);
			}
		}

		if (query.contains) {
			args.push('--contains', query.contains);
		}

		const result = await this.exec(args, { cancellationToken });

		const fn = (line: string): Ref | null => {
			let match: RegExpExecArray | null;

			if (match = /^refs\/heads\/([^ ]+) ([0-9a-f]{40}) ([0-9a-f]{40})?$/.exec(line)) {
				return { name: match[1], commit: match[2], type: RefType.Head };
			} else if (match = /^refs\/remotes\/([^/]+)\/([^ ]+) ([0-9a-f]{40}) ([0-9a-f]{40})?$/.exec(line)) {
				return { name: `${match[1]}/${match[2]}`, commit: match[3], type: RefType.RemoteHead, remote: match[1] };
			} else if (match = /^refs\/tags\/([^ ]+) ([0-9a-f]{40}) ([0-9a-f]{40})?$/.exec(line)) {
				return { name: match[1], commit: match[3] ?? match[2], type: RefType.Tag };
			}

			return null;
		};

		return result.stdout.split('\n')
			.filter(line => !!line)
			.map(fn)
			.filter(ref => !!ref) as Ref[];
	}

	async getRemoteRefs(remote: string, opts?: { heads?: boolean; tags?: boolean; cancellationToken?: CancellationToken }): Promise<Ref[]> {
		if (opts?.cancellationToken && opts?.cancellationToken.isCancellationRequested) {
			throw new CancellationError();
		}

		const args = ['ls-remote'];

		if (opts?.heads) {
			args.push('--heads');
		}

		if (opts?.tags) {
			args.push('--tags');
		}

		args.push(remote);

		const result = await this.exec(args, { cancellationToken: opts?.cancellationToken });

		const fn = (line: string): Ref | null => {
			let match: RegExpExecArray | null;

			if (match = /^([0-9a-f]{40})\trefs\/heads\/([^ ]+)$/.exec(line)) {
				return { name: match[1], commit: match[2], type: RefType.Head };
			} else if (match = /^([0-9a-f]{40})\trefs\/tags\/([^ ]+)$/.exec(line)) {
				return { name: match[2], commit: match[1], type: RefType.Tag };
			}

			return null;
		};

		return result.stdout.split('\n')
			.filter(line => !!line)
			.map(fn)
			.filter(ref => !!ref) as Ref[];
	}

	async getStashes(): Promise<Stash[]> {
		const result = await this.exec(['stash', 'list', `--format=${STASH_FORMAT}`, '-z']);
		return parseGitStashes(result.stdout.trim());
	}

	async getRemotes(): Promise<Remote[]> {
		const remotes: MutableRemote[] = [];

		try {
			// Attempt to parse the config file
			remotes.push(...await this.getRemotesFS());

			if (remotes.length === 0) {
				this.logger.info('[Git][getRemotes] No remotes found in the git config file');
			}
		}
		catch (err) {
			this.logger.warn(`[Git][getRemotes] Error: ${err.message}`);

			// Fallback to using git to get the remotes
			remotes.push(...await this.getRemotesGit());
		}

		for (const remote of remotes) {
			// https://github.com/microsoft/vscode/issues/45271
			remote.isReadOnly = remote.pushUrl === undefined || remote.pushUrl === 'no_push';
		}

		return remotes;
	}

	private async getRemotesFS(): Promise<MutableRemote[]> {
		const raw = await fs.readFile(path.join(this.dotGit.commonPath ?? this.dotGit.path, 'config'), 'utf8');
		return parseGitRemotes(raw);
	}

	private async getRemotesGit(): Promise<MutableRemote[]> {
		const remotes: MutableRemote[] = [];

		const result = await this.exec(['remote', '--verbose']);
		const lines = result.stdout.trim().split('\n').filter(l => !!l);

		for (const line of lines) {
			const parts = line.split(/\s/);
			const [name, url, type] = parts;

			let remote = remotes.find(r => r.name === name);

			if (!remote) {
				remote = { name, isReadOnly: false };
				remotes.push(remote);
			}

			if (/fetch/i.test(type)) {
				remote.fetchUrl = url;
			} else if (/push/i.test(type)) {
				remote.pushUrl = url;
			} else {
				remote.fetchUrl = url;
				remote.pushUrl = url;
			}
		}

		return remotes;
	}

	async getBranch(name: string): Promise<Branch> {
		if (name === 'HEAD') {
			return this.getHEAD();
		}

		const args = ['for-each-ref'];

		let supportsAheadBehind = true;
		if (this._git.compareGitVersionTo('1.9.0') === -1) {
			args.push('--format=%(refname)%00%(upstream:short)%00%(objectname)');
			supportsAheadBehind = false;
		} else if (this._git.compareGitVersionTo('2.16.0') === -1) {
			args.push('--format=%(refname)%00%(upstream:short)%00%(objectname)%00%(upstream:track)');
		} else {
			args.push('--format=%(refname)%00%(upstream:short)%00%(objectname)%00%(upstream:track)%00%(upstream:remotename)%00%(upstream:remoteref)');
		}

		// On Windows and macOS ref names are case insensitive so we add --ignore-case
		// to handle the scenario where the user switched to a branch with incorrect
		// casing
		if (this.git.compareGitVersionTo('2.12') !== -1 && (isWindows || isMacintosh)) {
			args.push('--ignore-case');
		}

		if (/^refs\/(heads|remotes)\//i.test(name)) {
			args.push(name);
		} else {
			args.push(`refs/heads/${name}`, `refs/remotes/${name}`);
		}

		const result = await this.exec(args);
		const branches: Branch[] = result.stdout.trim().split('\n').map<Branch | undefined>(line => {
			let [branchName, upstream, ref, status, remoteName, upstreamRef] = line.trim().split('\0');

			if (branchName.startsWith('refs/heads/')) {
				branchName = branchName.substring(11);
				const index = upstream.indexOf('/');

				let ahead;
				let behind;
				const match = /\[(?:ahead ([0-9]+))?[,\s]*(?:behind ([0-9]+))?]|\[gone]/.exec(status);
				if (match) {
					[, ahead, behind] = match;
				}

				return {
					type: RefType.Head,
					name: branchName,
					upstream: upstream ? {
						name: upstreamRef ? upstreamRef.substring(11) : upstream.substring(index + 1),
						remote: remoteName ? remoteName : upstream.substring(0, index)
					} : undefined,
					commit: ref || undefined,
					ahead: Number(ahead) || 0,
					behind: Number(behind) || 0,
				};
			} else if (branchName.startsWith('refs/remotes/')) {
				branchName = branchName.substring(13);
				const index = branchName.indexOf('/');

				return {
					type: RefType.RemoteHead,
					name: branchName.substring(index + 1),
					remote: branchName.substring(0, index),
					commit: ref,
				};
			} else {
				return undefined;
			}
		}).filter((b?: Branch): b is Branch => !!b);

		if (branches.length) {
			const [branch] = branches;

			if (!supportsAheadBehind && branch.upstream) {
				try {
					const result = await this.exec(['rev-list', '--left-right', '--count', `${branch.name}...${branch.upstream.remote}/${branch.upstream.name}`]);
					const [ahead, behind] = result.stdout.trim().split('\t');

					(branch as any).ahead = Number(ahead) || 0;
					(branch as any).behind = Number(behind) || 0;
				} catch { }
			}

			return branch;
		}

		this.logger.warn(`[Git][getBranch] No such branch: ${name}`);
		return Promise.reject<Branch>(new Error(`No such branch: ${name}.`));
	}

	async getDefaultBranch(remoteName: string): Promise<Branch> {
		const result = await this.exec(['symbolic-ref', '--short', `refs/remotes/${remoteName}/HEAD`]);
		if (!result.stdout || result.stderr) {
			throw new Error('No default branch');
		}

		return this.getBranch(result.stdout.trim());
	}

	// TODO: Support core.commentChar
	stripCommitMessageComments(message: string): string {
		return message.replace(/^\s*#.*$\n?/gm, '').trim();
	}

	async getSquashMessage(): Promise<string | undefined> {
		const squashMsgPath = path.join(this.repositoryRoot, '.git', 'SQUASH_MSG');

		try {
			const raw = await fs.readFile(squashMsgPath, 'utf8');
			return this.stripCommitMessageComments(raw);
		} catch {
			return undefined;
		}
	}

	async getMergeMessage(): Promise<string | undefined> {
		const mergeMsgPath = path.join(this.repositoryRoot, '.git', 'MERGE_MSG');

		try {
			const raw = await fs.readFile(mergeMsgPath, 'utf8');
			return this.stripCommitMessageComments(raw);
		} catch {
			return undefined;
		}
	}

	async getCommitTemplate(): Promise<string> {
		try {
			const result = await this.exec(['config', '--get', 'commit.template']);

			if (!result.stdout) {
				return '';
			}

			// https://github.com/git/git/blob/3a0f269e7c82aa3a87323cb7ae04ac5f129f036b/path.c#L612
			const homedir = os.homedir();
			let templatePath = result.stdout.trim()
				.replace(/^~([^\/]*)\//, (_, user) => `${user ? path.join(path.dirname(homedir), user) : homedir}/`);

			if (!path.isAbsolute(templatePath)) {
				templatePath = path.join(this.repositoryRoot, templatePath);
			}

			const raw = await fs.readFile(templatePath, 'utf8');
			return this.stripCommitMessageComments(raw);
		} catch (err) {
			return '';
		}
	}

	async getCommit(ref: string): Promise<Commit> {
		const result = await this.exec(['show', '-s', '--decorate=full', '--shortstat', `--format=${COMMIT_FORMAT}`, '-z', ref]);
		const commits = parseGitCommits(result.stdout);
		if (commits.length === 0) {
			return Promise.reject<Commit>('bad commit format');
		}
		return commits[0];
	}

	async revList(ref1: string, ref2: string): Promise<string[]> {
		const result = await this.exec(['rev-list', `${ref1}..${ref2}`]);
		if (result.stderr) {
			return [];
		}

		return result.stdout.trim().split('\n');
	}

	async revParse(ref: string): Promise<string | undefined> {
		try {
			const result = await fs.readFile(path.join(this.dotGit.path, ref), 'utf8');
			return result.trim();
		} catch (err) {
			this.logger.warn(`[Git][revParse] Unable to read file: ${err.message}`);
		}

		try {
			const result = await this.exec(['rev-parse', ref]);
			if (result.stderr) {
				return undefined;
			}
			return result.stdout.trim();
		} catch (err) {
			return undefined;
		}
	}

	async updateSubmodules(paths: string[]): Promise<void> {
		const args = ['submodule', 'update'];

		for (const chunk of splitInChunks(paths.map(sanitizePath), MAX_CLI_LENGTH)) {
			await this.exec([...args, '--', ...chunk]);
		}
	}

	async getSubmodules(): Promise<Submodule[]> {
		const gitmodulesPath = path.join(this.root, '.gitmodules');

		try {
			const gitmodulesRaw = await fs.readFile(gitmodulesPath, 'utf8');
			return parseGitmodules(gitmodulesRaw);
		} catch (err) {
			if (/ENOENT/.test(err.message)) {
				return [];
			}

			throw err;
		}
	}
}