From bda851bda8a2ca2adcbb3cce070b26188bd1648a Mon Sep 17 00:00:00 2001
From: Matt Hinchliffe <matt.hinchliffe@ft.com>
Date: Fri, 23 Nov 2018 14:46:26 +0000
Subject: [PATCH 1/8] Add a check in the task runner to wait until tasks
 running in any depended upon packages are complete
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

 🐿 v2.10.0
---
 src/cli-task.js     |  2 +-
 src/run-parallel.js | 42 +++++++++++++++++++++++++++++++++++++-----
 src/wait-until.js   | 15 +++++++++++++++
 3 files changed, 53 insertions(+), 6 deletions(-)
 create mode 100644 src/wait-until.js

diff --git a/src/cli-task.js b/src/cli-task.js
index a217174..8084a25 100644
--- a/src/cli-task.js
+++ b/src/cli-task.js
@@ -39,7 +39,7 @@ module.exports = (task) => {
 			logger.info(`Running ${tasks.length} tasks`);
 
 			// 6. execute all tasks
-			await runParallel(tasks, globals.concurrency);
+			await runParallel(sortedPackages, tasks, globals.concurrency);
 
 			timer.stop();
 
diff --git a/src/run-parallel.js b/src/run-parallel.js
index a304f62..da6478b 100644
--- a/src/run-parallel.js
+++ b/src/run-parallel.js
@@ -1,14 +1,46 @@
+const Semaphore = require('async-sema');
 const logger = require('./logger');
-const Sema = require('async-sema');
+const waitUntil = require('./wait-until');
 
-module.exports = (tasks = [], concurrency = 1) => {
-	const sema = new Sema(concurrency);
+const noRunningDependencies = (running, dependencies) => {
+	return !dependencies.some((dependency) => running.has(dependency));
+};
+
+module.exports = (packages = [], tasks = [], concurrency = 1) => {
+	const semaphore = new Semaphore(concurrency);
 
 	logger.info(`Executing up to ${concurrency} tasks at a time`);
 
+	const packagesRunning = new Set();
+
 	return Promise.all(
-		tasks.map((task) => {
-			return sema.acquire().then(task).then(() => sema.release());
+		tasks.map((task, i) => {
+			// TODO: number of tasks ~= number of packages
+			const packageName = packages[i].name;
+			const packageManifest = packages[i].manifest;
+
+			const allDependencies = Object.keys({
+				...packageManifest.dependencies,
+				...packageManifest.devDependencies,
+				...packageManifest.peerDependencies,
+				...packageManifest.optionalDependencies
+			});
+
+			return semaphore
+				.acquire()
+				.then(() => {
+					return waitUntil(() => {
+						return noRunningDependencies(packagesRunning, allDependencies);
+					});
+				})
+				.then(() => {
+					packagesRunning.add(packageName);
+					return task();
+				})
+				.then(() => {
+					packagesRunning.delete(packageName);
+					return semaphore.release();
+				});
 		})
 	);
 };
diff --git a/src/wait-until.js b/src/wait-until.js
new file mode 100644
index 0000000..edd0faa
--- /dev/null
+++ b/src/wait-until.js
@@ -0,0 +1,15 @@
+const wait = (ms = 100) => new Promise((resolve) => setTimeout(resolve, ms));
+
+module.exports = (check) => {
+	return new Promise((resolve) => {
+		const test = () => {
+			if (check()) {
+				resolve();
+			} else {
+				wait().then(test);
+			}
+		};
+
+		test();
+	});
+};

From a9be892c382d6c6316874aaa8c96eac8b8e5b188 Mon Sep 17 00:00:00 2001
From: Matt Hinchliffe <matt@maketea.co.uk>
Date: Fri, 7 Dec 2018 08:29:19 +0000
Subject: [PATCH 2/8] =?UTF-8?q?Refactor=20tasks=20to=20return=20package=20?=
 =?UTF-8?q?instance=20with=20callback=20function=20=20=F0=9F=90=BF=20v2.10?=
 =?UTF-8?q?.0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/cli-task.js                |  2 +-
 src/run-parallel.js            | 22 +++++++++-------------
 src/sort-packages.js           |  1 +
 src/tasks/exec.js              |  3 ++-
 src/tasks/publish.js           |  3 ++-
 src/tasks/run.js               |  3 ++-
 src/tasks/script.js            |  3 ++-
 src/tasks/version.js           |  4 +++-
 test/src/tasks/exec.spec.js    | 13 ++++++-------
 test/src/tasks/publish.spec.js | 13 ++++++-------
 test/src/tasks/run.spec.js     | 13 ++++++-------
 test/src/tasks/script.spec.js  | 13 ++++++-------
 test/src/tasks/version.spec.js |  5 +++--
 13 files changed, 49 insertions(+), 49 deletions(-)

diff --git a/src/cli-task.js b/src/cli-task.js
index 8084a25..a217174 100644
--- a/src/cli-task.js
+++ b/src/cli-task.js
@@ -39,7 +39,7 @@ module.exports = (task) => {
 			logger.info(`Running ${tasks.length} tasks`);
 
 			// 6. execute all tasks
-			await runParallel(sortedPackages, tasks, globals.concurrency);
+			await runParallel(tasks, globals.concurrency);
 
 			timer.stop();
 
diff --git a/src/run-parallel.js b/src/run-parallel.js
index da6478b..3f7e7a3 100644
--- a/src/run-parallel.js
+++ b/src/run-parallel.js
@@ -6,7 +6,7 @@ const noRunningDependencies = (running, dependencies) => {
 	return !dependencies.some((dependency) => running.has(dependency));
 };
 
-module.exports = (packages = [], tasks = [], concurrency = 1) => {
+module.exports = (tasks = [], concurrency = 1) => {
 	const semaphore = new Semaphore(concurrency);
 
 	logger.info(`Executing up to ${concurrency} tasks at a time`);
@@ -14,16 +14,12 @@ module.exports = (packages = [], tasks = [], concurrency = 1) => {
 	const packagesRunning = new Set();
 
 	return Promise.all(
-		tasks.map((task, i) => {
-			// TODO: number of tasks ~= number of packages
-			const packageName = packages[i].name;
-			const packageManifest = packages[i].manifest;
-
+		tasks.map(({ pkg, apply }) => {
 			const allDependencies = Object.keys({
-				...packageManifest.dependencies,
-				...packageManifest.devDependencies,
-				...packageManifest.peerDependencies,
-				...packageManifest.optionalDependencies
+				...pkg.manifest.dependencies,
+				...pkg.manifest.devDependencies,
+				...pkg.manifest.peerDependencies,
+				...pkg.manifest.optionalDependencies
 			});
 
 			return semaphore
@@ -34,11 +30,11 @@ module.exports = (packages = [], tasks = [], concurrency = 1) => {
 					});
 				})
 				.then(() => {
-					packagesRunning.add(packageName);
-					return task();
+					packagesRunning.add(pkg.name);
+					return apply();
 				})
 				.then(() => {
-					packagesRunning.delete(packageName);
+					packagesRunning.delete(pkg.name);
 					return semaphore.release();
 				});
 		})
diff --git a/src/sort-packages.js b/src/sort-packages.js
index aa02306..659a3bc 100644
--- a/src/sort-packages.js
+++ b/src/sort-packages.js
@@ -1,6 +1,7 @@
 const toposort = require('toposort');
 
 const collateDependencies = (manifest) => {
+	// TODO: refactor into package class
 	return Object.keys({
 		...manifest.dependencies,
 		...manifest.devDependencies,
diff --git a/src/tasks/exec.js b/src/tasks/exec.js
index a987cf4..c4f9bd0 100644
--- a/src/tasks/exec.js
+++ b/src/tasks/exec.js
@@ -3,7 +3,8 @@ const runPackage = require('../run-package');
 
 function exec (packages = [], command, args = []) {
 	return packages.map((pkg) => {
-		return () => runPackage(command, args, pkg.location);
+		const apply = () => runPackage(command, args, pkg.location);
+		return { pkg, apply };
 	});
 };
 
diff --git a/src/tasks/publish.js b/src/tasks/publish.js
index a611428..798ab9e 100644
--- a/src/tasks/publish.js
+++ b/src/tasks/publish.js
@@ -10,7 +10,8 @@ function publish (packages = [], args = []) {
 
 	// create a queue of tasks to run
 	return filteredPackages.map((pkg) => {
-		return () => runPackage('npm', ['publish', ...args], pkg.location);
+		const apply = () => runPackage('npm', ['publish', ...args], pkg.location);
+		return { pkg, apply };
 	});
 };
 
diff --git a/src/tasks/run.js b/src/tasks/run.js
index 998fb3c..9e8b208 100644
--- a/src/tasks/run.js
+++ b/src/tasks/run.js
@@ -12,7 +12,8 @@ function run (packages = [], script) {
 
 	// create a queue of tasks to run
 	return filteredPackages.map((pkg) => {
-		return () => runPackage('npm', ['run', script], pkg.location);
+		const apply = () => runPackage('npm', ['run', script], pkg.location);
+		return { pkg, apply };
 	});
 };
 
diff --git a/src/tasks/script.js b/src/tasks/script.js
index 6e611ce..77c57a4 100644
--- a/src/tasks/script.js
+++ b/src/tasks/script.js
@@ -6,7 +6,8 @@ function script (packages = [], scriptPath) {
 	const resolvedScript = path.resolve(process.cwd(), scriptPath);
 
 	return packages.map((pkg) => {
-		return () => runPackage('node', [resolvedScript], pkg.location);
+		const apply = () => runPackage('node', [resolvedScript], pkg.location);
+		return { pkg, apply };
 	});
 }
 
diff --git a/src/tasks/version.js b/src/tasks/version.js
index 7faaa84..d102b7f 100644
--- a/src/tasks/version.js
+++ b/src/tasks/version.js
@@ -16,10 +16,12 @@ function version (packages = [], tag) {
 	const packageNames = new Set(packages.map((pkg) => pkg.name));
 
 	return packages.map((pkg) => {
-		return () => {
+		const apply = () => {
 			const newManifest = updateVersions(pkg.manifest, number, packageNames);
 			return pkg.writeManifest(newManifest);
 		};
+
+		return { pkg, apply };
 	});
 };
 
diff --git a/test/src/tasks/exec.spec.js b/test/src/tasks/exec.spec.js
index 797af1f..f8fb776 100644
--- a/test/src/tasks/exec.spec.js
+++ b/test/src/tasks/exec.spec.js
@@ -31,11 +31,12 @@ describe('src/tasks/exec', () => {
 		mockRun.mockReset();
 	});
 
-	it('it returns an array of functions', () => {
+	it('it returns an array of tasks', () => {
 		expect(result).toBeInstanceOf(Array);
 
 		result.forEach((item) => {
-			expect(item).toBeInstanceOf(Function);
+			expect(item.pkg).toBeDefined();
+			expect(item.apply).toEqual(expect.any(Function));
 		});
 	});
 
@@ -44,12 +45,10 @@ describe('src/tasks/exec', () => {
 	});
 
 	it('provides the correct arguments to run helper', () => {
-		result.forEach((item, i) => {
-			const pkg = packages[i];
-
-			item();
+		result.forEach((item) => {
+			item.apply();
 
-			expect(mockRun).toHaveBeenCalledWith(command, args, pkg.location);
+			expect(mockRun).toHaveBeenCalledWith(command, args, item.pkg.location);
 		});
 	});
 });
diff --git a/test/src/tasks/publish.spec.js b/test/src/tasks/publish.spec.js
index accb190..88a2a5b 100644
--- a/test/src/tasks/publish.spec.js
+++ b/test/src/tasks/publish.spec.js
@@ -30,11 +30,12 @@ describe('src/tasks/publish', () => {
 		mockRun.mockReset();
 	});
 
-	it('it returns an array of functions', () => {
+	it('it returns an array of tasks', () => {
 		expect(result).toBeInstanceOf(Array);
 
 		result.forEach((item) => {
-			expect(item).toBeInstanceOf(Function);
+			expect(item.pkg).toBeDefined();
+			expect(item.apply).toEqual(expect.any(Function));
 		});
 	});
 
@@ -43,12 +44,10 @@ describe('src/tasks/publish', () => {
 	});
 
 	it('provides the correct arguments to run helper', () => {
-		result.forEach((item, i) => {
-			const pkg = packages[i];
-
-			item();
+		result.forEach((item) => {
+			item.apply();
 
-			expect(mockRun).toHaveBeenCalledWith('npm', ['publish'].concat(args), pkg.location);
+			expect(mockRun).toHaveBeenCalledWith('npm', ['publish'].concat(args), item.pkg.location);
 		});
 	});
 });
diff --git a/test/src/tasks/run.spec.js b/test/src/tasks/run.spec.js
index bd7d33e..5413f7b 100644
--- a/test/src/tasks/run.spec.js
+++ b/test/src/tasks/run.spec.js
@@ -30,11 +30,12 @@ describe('src/tasks/run', () => {
 		mockRun.mockReset();
 	});
 
-	it('it returns an array of functions', () => {
+	it('it returns an array of tasks', () => {
 		expect(result).toBeInstanceOf(Array);
 
 		result.forEach((item) => {
-			expect(item).toBeInstanceOf(Function);
+			expect(item.pkg).toBeDefined();
+			expect(item.apply).toEqual(expect.any(Function));
 		});
 	});
 
@@ -43,12 +44,10 @@ describe('src/tasks/run', () => {
 	});
 
 	it('provides the correct arguments to run helper', () => {
-		result.forEach((item, i) => {
-			const pkg = packages[i];
-
-			item();
+		result.forEach((item) => {
+			item.apply();
 
-			expect(mockRun).toHaveBeenCalledWith('npm', ['run', command], pkg.location);
+			expect(mockRun).toHaveBeenCalledWith('npm', ['run', command], item.pkg.location);
 		});
 	});
 });
diff --git a/test/src/tasks/script.spec.js b/test/src/tasks/script.spec.js
index 15cb41a..3d3da3f 100644
--- a/test/src/tasks/script.spec.js
+++ b/test/src/tasks/script.spec.js
@@ -29,11 +29,12 @@ describe('src/tasks/script', () => {
 		mockRun.mockReset();
 	});
 
-	it('it returns an array of functions', () => {
+	it('it returns an array of tasks', () => {
 		expect(result).toBeInstanceOf(Array);
 
 		result.forEach((item) => {
-			expect(item).toBeInstanceOf(Function);
+			expect(item.pkg).toBeDefined();
+			expect(item.apply).toEqual(expect.any(Function));
 		});
 	});
 
@@ -44,12 +45,10 @@ describe('src/tasks/script', () => {
 	it('provides the correct arguments to run helper', () => {
 		const resolvedPath = process.cwd() + '/' + scriptPath;
 
-		result.forEach((item, i) => {
-			const pkg = packages[i];
-
-			item();
+		result.forEach((item) => {
+			item.apply();
 
-			expect(mockRun).toHaveBeenCalledWith('node', [ resolvedPath ], pkg.location);
+			expect(mockRun).toHaveBeenCalledWith('node', [ resolvedPath ], item.pkg.location);
 		});
 	});
 });
diff --git a/test/src/tasks/version.spec.js b/test/src/tasks/version.spec.js
index 3cc3b19..39bcd57 100644
--- a/test/src/tasks/version.spec.js
+++ b/test/src/tasks/version.spec.js
@@ -29,11 +29,12 @@ describe('src/tasks/version', () => {
 		mockRun.mockReset();
 	});
 
-	it('it returns an array of functions', () => {
+	it('it returns an array of tasks', () => {
 		expect(result).toBeInstanceOf(Array);
 
 		result.forEach((item) => {
-			expect(item).toBeInstanceOf(Function);
+			expect(item.pkg).toBeDefined();
+			expect(item.apply).toEqual(expect.any(Function));
 		});
 	});
 

From 8941bb16a47d320b5794c7d5bc860ad829830479 Mon Sep 17 00:00:00 2001
From: Matt Hinchliffe <matt@maketea.co.uk>
Date: Fri, 7 Dec 2018 08:40:41 +0000
Subject: [PATCH 3/8] =?UTF-8?q?Refactor=20logic=20to=20fetch=20all=20depen?=
 =?UTF-8?q?dencies=20into=20package=20class=20=20=F0=9F=90=BF=20v2.10.0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/package.js           |  9 +++++++++
 src/run-parallel.js      |  9 +--------
 src/sort-packages.js     |  4 +---
 test/src/package.spec.js | 18 +++++++++++++++++-
 4 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/src/package.js b/src/package.js
index a220d76..7c6c258 100644
--- a/src/package.js
+++ b/src/package.js
@@ -31,6 +31,15 @@ class Package {
 		return path.relative(process.cwd(), this.location);
 	}
 
+	get allDependencies () {
+		return Object.keys({
+			...this.manifest.dependencies,
+			...this.manifest.devDependencies,
+			...this.manifest.peerDependencies,
+			...this.manifest.optionalDependencies
+		});
+	};
+
 	async writeManifest (manifest) {
 		const json = JSON.stringify(manifest, null, 2);
 		await writeFile(this.manifestLocation, json);
diff --git a/src/run-parallel.js b/src/run-parallel.js
index 3f7e7a3..a15ef18 100644
--- a/src/run-parallel.js
+++ b/src/run-parallel.js
@@ -15,18 +15,11 @@ module.exports = (tasks = [], concurrency = 1) => {
 
 	return Promise.all(
 		tasks.map(({ pkg, apply }) => {
-			const allDependencies = Object.keys({
-				...pkg.manifest.dependencies,
-				...pkg.manifest.devDependencies,
-				...pkg.manifest.peerDependencies,
-				...pkg.manifest.optionalDependencies
-			});
-
 			return semaphore
 				.acquire()
 				.then(() => {
 					return waitUntil(() => {
-						return noRunningDependencies(packagesRunning, allDependencies);
+						return noRunningDependencies(packagesRunning, pkg.allDependencies);
 					});
 				})
 				.then(() => {
diff --git a/src/sort-packages.js b/src/sort-packages.js
index 659a3bc..c3fabd1 100644
--- a/src/sort-packages.js
+++ b/src/sort-packages.js
@@ -14,9 +14,7 @@ module.exports = (reverse = false, packages = []) => {
 	const packageNames = new Set(packages.map((pkg) => pkg.name));
 
 	const edges = packages.reduce((edges, pkg) => {
-		const dependencyNames = collateDependencies(pkg.manifest);
-
-		const localDependencies = dependencyNames.filter((dependency) => {
+		const localDependencies = pkg.allDependencies.filter((dependency) => {
 			return packageNames.has(dependency);
 		});
 
diff --git a/test/src/package.spec.js b/test/src/package.spec.js
index 3932d38..fe6cee3 100644
--- a/test/src/package.spec.js
+++ b/test/src/package.spec.js
@@ -6,6 +6,14 @@ const Subject = require('../../src/package');
 const fixture = Object.freeze({
 	name: 'my-package',
 	version: '0.0.0',
+	dependencies: {
+		lodash: '^3.0.0',
+		hyperons: '^0.5.0'
+	},
+	devDependencies: {
+		jest: '^16.0.0',
+		prettier: '^12.0.0'
+	}
 });
 
 describe('src/package', () => {
@@ -53,6 +61,14 @@ describe('src/package', () => {
 		});
 	});
 
+	describe('get #allDependencies', () => {
+		it('returns a list of all dependencies', () => {
+			const instance = factory(fixture);
+			expect(instance.allDependencies).toBeInstanceOf(Array);
+			expect(instance.allDependencies.length).toEqual(4);
+		});
+	})
+
 	describe('#writeManifest', () => {
 		beforeEach(() => {
 			// The final arg is a callback that needs calling!
@@ -65,7 +81,7 @@ describe('src/package', () => {
 
 			expect(fs.writeFile).toHaveBeenCalledWith(
 				'/root/path/to/package/package.json',
-				JSON.stringify({ name : 'my-package', version: '1.0.0' }, null, 2),
+				JSON.stringify({ ...fixture, version: '1.0.0' }, null, 2),
 				expect.any(Function)
 			);
 		});

From 64c637b4bef63a34bd0e08676a50458775142f3c Mon Sep 17 00:00:00 2001
From: Matt Hinchliffe <matt@maketea.co.uk>
Date: Fri, 7 Dec 2018 08:55:02 +0000
Subject: [PATCH 4/8] Refactor specs to use shared package helper
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

 🐿 v2.10.0
---
 src/sort-packages.js           | 10 -------
 test/helpers/create-package.js | 10 +++++++
 test/src/package.spec.js       |  2 +-
 test/src/sort-packages.spec.js | 50 +++++++++++++---------------------
 test/src/tasks/exec.spec.js    |  8 +-----
 test/src/tasks/publish.spec.js |  9 +-----
 test/src/tasks/run.spec.js     | 15 +++-------
 test/src/tasks/script.spec.js  |  8 +-----
 test/src/tasks/version.spec.js |  8 +-----
 9 files changed, 38 insertions(+), 82 deletions(-)
 create mode 100644 test/helpers/create-package.js

diff --git a/src/sort-packages.js b/src/sort-packages.js
index c3fabd1..b1ef7c7 100644
--- a/src/sort-packages.js
+++ b/src/sort-packages.js
@@ -1,15 +1,5 @@
 const toposort = require('toposort');
 
-const collateDependencies = (manifest) => {
-	// TODO: refactor into package class
-	return Object.keys({
-		...manifest.dependencies,
-		...manifest.devDependencies,
-		...manifest.peerDependencies,
-		...manifest.optionalDependencies
-	});
-};
-
 module.exports = (reverse = false, packages = []) => {
 	const packageNames = new Set(packages.map((pkg) => pkg.name));
 
diff --git a/test/helpers/create-package.js b/test/helpers/create-package.js
new file mode 100644
index 0000000..6be7e86
--- /dev/null
+++ b/test/helpers/create-package.js
@@ -0,0 +1,10 @@
+const Package = require('../../src/package');
+
+module.exports = (name, options = {}) => {
+	const manifest = { name, ...options };
+	const instance = new Package(manifest, `/Path/to/${name}`);
+
+	instance.writeManifest = jest.fn();
+
+	return instance;
+};
diff --git a/test/src/package.spec.js b/test/src/package.spec.js
index fe6cee3..9ced93c 100644
--- a/test/src/package.spec.js
+++ b/test/src/package.spec.js
@@ -67,7 +67,7 @@ describe('src/package', () => {
 			expect(instance.allDependencies).toBeInstanceOf(Array);
 			expect(instance.allDependencies.length).toEqual(4);
 		});
-	})
+	});
 
 	describe('#writeManifest', () => {
 		beforeEach(() => {
diff --git a/test/src/sort-packages.spec.js b/test/src/sort-packages.spec.js
index 7dcbc16..d58b0ca 100644
--- a/test/src/sort-packages.spec.js
+++ b/test/src/sort-packages.spec.js
@@ -1,39 +1,27 @@
 const subject = require('../../src/sort-packages');
+const createPackage = require('../helpers/create-package');
 
-const fixture = Object.freeze([
-	{
-		name: 'foo',
-		manifest: {
-			dependencies: {
-				qux: '0.0.0'
-			}
+const fixture = [
+	createPackage('foo', {
+		dependencies: {
+			qux: '0.0.0'
 		}
-	},
-	{
-		name: 'bar',
-		manifest: {
-			dependencies: {
-				baz: '0.0.0'
-			}
+	}),
+	createPackage('bar', {
+		dependencies: {
+			baz: '0.0.0'
 		}
-	},
-	{
-		name: 'baz',
-		manifest: {
-			dependencies: {
-				foo: '0.0.0',
-				qux: '0.0.0'
-			}
-		},
-	},
-	{
-		name: 'qux',
-		manifest: {
-			dependencies: {
-			}
+	}),
+	createPackage('baz', {
+		dependencies: {
+			foo: '0.0.0',
+			qux: '0.0.0'
 		}
-	}
-]);
+	}),
+	createPackage('qux', {
+		dependencies: {}
+	})
+];
 
 describe('src/sort-packages', () => {
 	it('returns a new array', () => {
diff --git a/test/src/tasks/exec.spec.js b/test/src/tasks/exec.spec.js
index f8fb776..205aed8 100644
--- a/test/src/tasks/exec.spec.js
+++ b/test/src/tasks/exec.spec.js
@@ -2,13 +2,7 @@ const mockRun = jest.fn();
 jest.mock('../../../src/run-package', () => mockRun);
 
 const { task: subject } = require('../../../src/tasks/exec');
-
-const createPackage = (name) => (
-	{
-		name,
-		location: `/Path/to/${name}`
-	}
-);
+const createPackage = require('../../helpers/create-package');
 
 describe('src/tasks/exec', () => {
 	const packages = [
diff --git a/test/src/tasks/publish.spec.js b/test/src/tasks/publish.spec.js
index 88a2a5b..31edec0 100644
--- a/test/src/tasks/publish.spec.js
+++ b/test/src/tasks/publish.spec.js
@@ -2,14 +2,7 @@ const mockRun = jest.fn();
 jest.mock('../../../src/run-package', () => mockRun);
 
 const { task: subject } = require('../../../src/tasks/publish');
-
-const createPackage = (name, options = {}) => (
-	{
-		name,
-		location: `/Path/to/${name}`,
-		...options
-	}
-);
+const createPackage = require('../../helpers/create-package');
 
 describe('src/tasks/publish', () => {
 	const packages = [
diff --git a/test/src/tasks/run.spec.js b/test/src/tasks/run.spec.js
index 5413f7b..392d643 100644
--- a/test/src/tasks/run.spec.js
+++ b/test/src/tasks/run.spec.js
@@ -2,20 +2,13 @@ const mockRun = jest.fn();
 jest.mock('../../../src/run-package', () => mockRun);
 
 const { task: subject } = require('../../../src/tasks/run');
-
-const createPackage = (name, options = {}) => (
-	{
-		name,
-		location: `/Path/to/${name}`,
-		...options
-	}
-);
+const createPackage = require('../../helpers/create-package');
 
 describe('src/tasks/run', () => {
 	const packages = [
-		createPackage('foo', { manifest: { scripts: { test: '' } } }),
-		createPackage('bar', { manifest: { scripts: { test: '' } } }),
-		createPackage('baz', { manifest: {} }),
+		createPackage('foo', { scripts: { test: '' } }),
+		createPackage('bar', { scripts: { test: '' } }),
+		createPackage('baz', { scripts: {} }),
 	];
 
 	const command = 'test';
diff --git a/test/src/tasks/script.spec.js b/test/src/tasks/script.spec.js
index 3d3da3f..0aa2638 100644
--- a/test/src/tasks/script.spec.js
+++ b/test/src/tasks/script.spec.js
@@ -2,13 +2,7 @@ const mockRun = jest.fn();
 jest.mock('../../../src/run-package', () => mockRun);
 
 const { task: subject } = require('../../../src/tasks/script');
-
-const createPackage = (name) => (
-	{
-		name,
-		location: `/Path/to/${name}`
-	}
-);
+const createPackage = require('../../helpers/create-package');
 
 describe('src/tasks/script', () => {
 	const packages = [
diff --git a/test/src/tasks/version.spec.js b/test/src/tasks/version.spec.js
index 39bcd57..4e0bd0b 100644
--- a/test/src/tasks/version.spec.js
+++ b/test/src/tasks/version.spec.js
@@ -2,13 +2,7 @@ const mockRun = jest.fn();
 jest.mock('../../../src/run-package', () => mockRun);
 
 const { task: subject } = require('../../../src/tasks/version');
-
-const createPackage = (name) => (
-	{
-		name,
-		location: `/Path/to/${name}`
-	}
-);
+const createPackage = require('../../helpers/create-package');
 
 describe('src/tasks/version', () => {
 	const packages = [

From cda9d8d64f5cffc46193827b5ecf954fb0051156 Mon Sep 17 00:00:00 2001
From: Matt Hinchliffe <matt.hinchliffe@ft.com>
Date: Fri, 7 Dec 2018 11:26:02 +0000
Subject: [PATCH 5/8] =?UTF-8?q?Refactor=20queue=20logic=20from=20a=20polle?=
 =?UTF-8?q?r=20(wait=20until...)=20to=20use=20an=20event=20emitter=20=20?=
 =?UTF-8?q?=F0=9F=90=BF=20v2.10.0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/event-queue.js  | 37 +++++++++++++++++++++++++++++++++++++
 src/run-parallel.js | 19 +++++++------------
 src/wait-until.js   | 15 ---------------
 3 files changed, 44 insertions(+), 27 deletions(-)
 create mode 100644 src/event-queue.js
 delete mode 100644 src/wait-until.js

diff --git a/src/event-queue.js b/src/event-queue.js
new file mode 100644
index 0000000..fe40e62
--- /dev/null
+++ b/src/event-queue.js
@@ -0,0 +1,37 @@
+const EventEmitter = require('events');
+
+class EventQueue extends EventEmitter {
+	constructor() {
+		super();
+		this.queue = new Set();
+	}
+
+	add(item) {
+		this.queue.add(item);
+		this.emit('queue:add', item);
+	}
+
+	delete(item) {
+		this.queue.delete(item);
+		this.emit('queue:delete', item);
+	}
+
+	// Resolves when the queue contains none of the given items
+	done(items = []) {
+		return new Promise((resolve) => {
+			const callback = () => {
+				const noItemsRunning = items.every((item) => !this.queue.has(item));
+
+				if (noItemsRunning) {
+					this.off('queue:delete', callback);
+					resolve();
+				}
+			};
+
+			this.on('queue:delete', callback);
+			callback();
+		});
+	}
+}
+
+module.exports = EventQueue;
diff --git a/src/run-parallel.js b/src/run-parallel.js
index a15ef18..bd95d15 100644
--- a/src/run-parallel.js
+++ b/src/run-parallel.js
@@ -1,33 +1,28 @@
 const Semaphore = require('async-sema');
 const logger = require('./logger');
-const waitUntil = require('./wait-until');
-
-const noRunningDependencies = (running, dependencies) => {
-	return !dependencies.some((dependency) => running.has(dependency));
-};
+const EventQueue = require('./event-queue');
 
 module.exports = (tasks = [], concurrency = 1) => {
 	const semaphore = new Semaphore(concurrency);
+	const queue = new EventQueue();
 
 	logger.info(`Executing up to ${concurrency} tasks at a time`);
 
-	const packagesRunning = new Set();
-
 	return Promise.all(
 		tasks.map(({ pkg, apply }) => {
 			return semaphore
 				.acquire()
 				.then(() => {
-					return waitUntil(() => {
-						return noRunningDependencies(packagesRunning, pkg.allDependencies);
-					});
+					// Queue the package now to maintain running order...
+					queue.add(pkg.name);
+					// ...but wait for any dependencies in the queue to finish
+					return queue.done(pkg.allDependencies);
 				})
 				.then(() => {
-					packagesRunning.add(pkg.name);
 					return apply();
 				})
 				.then(() => {
-					packagesRunning.delete(pkg.name);
+					queue.delete(pkg.name);
 					return semaphore.release();
 				});
 		})
diff --git a/src/wait-until.js b/src/wait-until.js
deleted file mode 100644
index edd0faa..0000000
--- a/src/wait-until.js
+++ /dev/null
@@ -1,15 +0,0 @@
-const wait = (ms = 100) => new Promise((resolve) => setTimeout(resolve, ms));
-
-module.exports = (check) => {
-	return new Promise((resolve) => {
-		const test = () => {
-			if (check()) {
-				resolve();
-			} else {
-				wait().then(test);
-			}
-		};
-
-		test();
-	});
-};

From f74bb551c7ac5596ad75c0bb7388ff0420af791d Mon Sep 17 00:00:00 2001
From: Matt Hinchliffe <matt.hinchliffe@ft.com>
Date: Fri, 7 Dec 2018 14:31:22 +0000
Subject: [PATCH 6/8] Add a spec for evented queue module
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

 🐿 v2.10.0
---
 src/event-queue.js           | 20 ++++++------
 src/run-parallel.js          |  2 +-
 test/src/event-queue.spec.js | 61 ++++++++++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+), 11 deletions(-)
 create mode 100644 test/src/event-queue.spec.js

diff --git a/src/event-queue.js b/src/event-queue.js
index fe40e62..5f775dc 100644
--- a/src/event-queue.js
+++ b/src/event-queue.js
@@ -8,28 +8,28 @@ class EventQueue extends EventEmitter {
 
 	add(item) {
 		this.queue.add(item);
-		this.emit('queue:add', item);
+		this.emit('add', item);
 	}
 
 	delete(item) {
 		this.queue.delete(item);
-		this.emit('queue:delete', item);
+		this.emit('delete', item);
 	}
 
-	// Resolves when the queue contains none of the given items
-	done(items = []) {
+	waitFor(items = []) {
 		return new Promise((resolve) => {
-			const callback = () => {
-				const noItemsRunning = items.every((item) => !this.queue.has(item));
+			const callback = (item) => {
+				const itemsRunning = items.some((item) => this.queue.has(item));
 
-				if (noItemsRunning) {
-					this.off('queue:delete', callback);
+				if (!itemsRunning) {
+					this.off('delete', callback);
 					resolve();
 				}
 			};
 
-			this.on('queue:delete', callback);
-			callback();
+			this.on('delete', callback);
+
+			callback(null);
 		});
 	}
 }
diff --git a/src/run-parallel.js b/src/run-parallel.js
index bd95d15..eb27a38 100644
--- a/src/run-parallel.js
+++ b/src/run-parallel.js
@@ -16,7 +16,7 @@ module.exports = (tasks = [], concurrency = 1) => {
 					// Queue the package now to maintain running order...
 					queue.add(pkg.name);
 					// ...but wait for any dependencies in the queue to finish
-					return queue.done(pkg.allDependencies);
+					return queue.waitFor(pkg.allDependencies);
 				})
 				.then(() => {
 					return apply();
diff --git a/test/src/event-queue.spec.js b/test/src/event-queue.spec.js
new file mode 100644
index 0000000..d15a37c
--- /dev/null
+++ b/test/src/event-queue.spec.js
@@ -0,0 +1,61 @@
+const Subject = require('../../src/event-queue');
+
+describe('src/event-queue', () => {
+	let instance;
+
+	beforeEach(() => {
+		instance = new Subject();
+	});
+
+	describe('#add', () => {
+		it('adds the given item to the queue', () => {
+			instance.add('foo');
+			expect(instance.queue.size).toEqual(1);
+		});
+
+		it('emits an event when items are added to the queue', (done) => {
+			instance.on('add', () => {
+				done();
+			});
+
+			instance.add('foo');
+		});
+	});
+
+	describe('#delete', () => {
+		it('removes the given item to the queue', () => {
+			instance.add('foo');
+			expect(instance.queue.size).toEqual(1);
+
+			instance.delete('foo');
+			expect(instance.queue.size).toEqual(0);
+		});
+
+		it('emits an event when items are removed from the queue', (done) => {
+			instance.add('foo');
+
+			instance.on('delete', (item) => {
+				done();
+			});
+
+			instance.delete('foo');
+		});
+	});
+
+	describe('#waitFor', () => {
+		it('resolves when the queue no longer contains any of the given items', (done) => {
+			instance.add('foo');
+			instance.add('bar');
+			instance.add('baz');
+
+			instance.waitFor(['foo', 'bar', 'baz']).then(() => {
+				expect(instance.queue.size).toEqual(0);
+				done();
+			});
+
+			instance.delete('foo');
+			instance.delete('bar');
+			instance.delete('baz');
+		});
+	});
+});

From c096ff54ad7df2b46e77827da7d6f4dd2e035194 Mon Sep 17 00:00:00 2001
From: Matt Hinchliffe <matt@maketea.co.uk>
Date: Wed, 12 Dec 2018 08:33:42 +0000
Subject: [PATCH 7/8] =?UTF-8?q?Ensure=20Node=208=20support=20by=20switchin?=
 =?UTF-8?q?g=20from=20eventemitter.off()=20to=20eventemitter.removeEvent()?=
 =?UTF-8?q?=20=20=F0=9F=90=BF=20v2.10.0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/{event-queue.js => evented-queue.js}      | 10 ++++++----
 src/run-parallel.js                           |  4 ++--
 ...nt-queue.spec.js => evented-queue.spec.js} | 20 ++++++++++---------
 3 files changed, 19 insertions(+), 15 deletions(-)
 rename src/{event-queue.js => evented-queue.js} (73%)
 rename test/src/{event-queue.spec.js => evented-queue.spec.js} (78%)

diff --git a/src/event-queue.js b/src/evented-queue.js
similarity index 73%
rename from src/event-queue.js
rename to src/evented-queue.js
index 5f775dc..a84d6af 100644
--- a/src/event-queue.js
+++ b/src/evented-queue.js
@@ -1,6 +1,6 @@
 const EventEmitter = require('events');
 
-class EventQueue extends EventEmitter {
+class EventedQueue extends EventEmitter {
 	constructor() {
 		super();
 		this.queue = new Set();
@@ -9,20 +9,22 @@ class EventQueue extends EventEmitter {
 	add(item) {
 		this.queue.add(item);
 		this.emit('add', item);
+		return this;
 	}
 
 	delete(item) {
 		this.queue.delete(item);
 		this.emit('delete', item);
+		return this;
 	}
 
 	waitFor(items = []) {
 		return new Promise((resolve) => {
-			const callback = (item) => {
+			const callback = () => {
 				const itemsRunning = items.some((item) => this.queue.has(item));
 
 				if (!itemsRunning) {
-					this.off('delete', callback);
+					this.removeListener('delete', callback);
 					resolve();
 				}
 			};
@@ -34,4 +36,4 @@ class EventQueue extends EventEmitter {
 	}
 }
 
-module.exports = EventQueue;
+module.exports = EventedQueue;
diff --git a/src/run-parallel.js b/src/run-parallel.js
index eb27a38..c49a3b6 100644
--- a/src/run-parallel.js
+++ b/src/run-parallel.js
@@ -1,10 +1,10 @@
 const Semaphore = require('async-sema');
 const logger = require('./logger');
-const EventQueue = require('./event-queue');
+const EventedQueue = require('./evented-queue');
 
 module.exports = (tasks = [], concurrency = 1) => {
 	const semaphore = new Semaphore(concurrency);
-	const queue = new EventQueue();
+	const queue = new EventedQueue();
 
 	logger.info(`Executing up to ${concurrency} tasks at a time`);
 
diff --git a/test/src/event-queue.spec.js b/test/src/evented-queue.spec.js
similarity index 78%
rename from test/src/event-queue.spec.js
rename to test/src/evented-queue.spec.js
index d15a37c..0a4feb0 100644
--- a/test/src/event-queue.spec.js
+++ b/test/src/evented-queue.spec.js
@@ -1,6 +1,6 @@
-const Subject = require('../../src/event-queue');
+const Subject = require('../../src/evented-queue');
 
-describe('src/event-queue', () => {
+describe('src/evented-queue', () => {
 	let instance;
 
 	beforeEach(() => {
@@ -34,7 +34,7 @@ describe('src/event-queue', () => {
 		it('emits an event when items are removed from the queue', (done) => {
 			instance.add('foo');
 
-			instance.on('delete', (item) => {
+			instance.on('delete', () => {
 				done();
 			});
 
@@ -44,18 +44,20 @@ describe('src/event-queue', () => {
 
 	describe('#waitFor', () => {
 		it('resolves when the queue no longer contains any of the given items', (done) => {
-			instance.add('foo');
-			instance.add('bar');
-			instance.add('baz');
+			instance
+				.add('foo')
+				.add('bar')
+				.add('baz');
 
 			instance.waitFor(['foo', 'bar', 'baz']).then(() => {
 				expect(instance.queue.size).toEqual(0);
 				done();
 			});
 
-			instance.delete('foo');
-			instance.delete('bar');
-			instance.delete('baz');
+			instance
+				.delete('foo')
+				.delete('bar')
+				.delete('baz');
 		});
 	});
 });

From f94c7e9e2ed1e4f5814a36a9be9d7008f00a6b70 Mon Sep 17 00:00:00 2001
From: Matt Hinchliffe <matt@maketea.co.uk>
Date: Thu, 13 Dec 2018 12:06:13 +0000
Subject: [PATCH 8/8] =?UTF-8?q?Add=20--preserve-order=20flag=20and=20refac?=
 =?UTF-8?q?tor=20queue=20to=20only=20enable=20waiting=20when=20the=20flag?=
 =?UTF-8?q?=20is=20on=20=20=F0=9F=90=BF=20v2.10.0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 readme.md           | 27 +++++++++++++++++----------
 src/bin/cli         |  6 +++++-
 src/cli-task.js     |  2 +-
 src/run-parallel.js | 10 +++++-----
 4 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/readme.md b/readme.md
index 99c8d39..92ded58 100644
--- a/readme.md
+++ b/readme.md
@@ -34,21 +34,21 @@ _Please note:_ Before executing a command Athloi will sort the packages [topolog
 
 ### exec
 
-Runs an arbitrary command in the scope of each package.
+Runs an arbitrary command within the scope of each package.
 
 ```sh
 athloi exec npm install
 ```
 
-A double-dash (`--`) is necessary to pass any dashed arguments to the script being executed.
+A double-dash (`--`) is necessary to pass any dashed arguments to the command being executed.
 
 ```sh
-athloi exec -- npm i -D
+athloi exec -- npm i -D lodash
 ```
 
 ### run
 
-Runs an [npm script] in each package that contains that script.
+Runs an [npm script] in each package that defines that script.
 
 ```sh
 athloi run build
@@ -66,7 +66,7 @@ athloi script path/to/task.js
 
 ### version
 
-Updates the release number for all packages and writes the new data back to `package.json`. The given tag must parseable as a valid semver number.
+Updates the release number for all public packages and writes the new data back to `package.json`. The given tag must parseable as a valid semver number.
 
 ```sh
 athloi version v1.0.0
@@ -93,18 +93,25 @@ athloi publish -- --access=public
 
 ### concurrency
 
-A global concurrency option which can be used to execute multiple tasks in parallel. By default only one task will run at a time.
+A global option which will execute up to the given number of tasks concurrently. By default one task will be run at a time.
 
 ```sh
-# run a build script 3 packages at a time
-athloi run build --concurrency 3
+# run a lint script in up to 3 packages at a time
+athloi run lint --concurrency 3
 ```
 
-_Please note:_ using a concurrency value higher than 1 no longer ensures that tasks will finish for packages which are dependencies of other packages.
+### preserve-order
+
+A global flag which will ensure tasks maintain topological sort order. When used with a concurrency value higher than 1 this option will force queued tasks to wait for any still running tasks in cross-dependent packages to finish first.
+
+```sh
+# run a concurrent build script but ensure dependencies are built first
+athloi run build --concurrency 5 --preserve-order
+```
 
 ### filter
 
-A global filter option which can be used for all tasks. It can filter packages based on the value of a field within their package manifest.
+A global option which can be used for all tasks. It filters packages based on the value of a field within their package manifest or the package name.
 
 ```sh
 # Run a build script in only the packages marked as private
diff --git a/src/bin/cli b/src/bin/cli
index 9700498..050d132 100755
--- a/src/bin/cli
+++ b/src/bin/cli
@@ -12,7 +12,11 @@ program
 	.option(
 		'-C, --concurrency <number>',
 		'Number of tasks to be run concurrently',
-		(arg) => /\d/.test(arg) ? parseInt(arg, 10) : undefined
+		(arg) => /^\d$/.test(arg) ? parseInt(arg, 10) : null
+	)
+	.option(
+		'-P, --preserve-order',
+		'Preserve topological sort order when running tasks concurrently'
 	)
 	.option(
 		'-R, --reverse',
diff --git a/src/cli-task.js b/src/cli-task.js
index a217174..f4d8ce1 100644
--- a/src/cli-task.js
+++ b/src/cli-task.js
@@ -39,7 +39,7 @@ module.exports = (task) => {
 			logger.info(`Running ${tasks.length} tasks`);
 
 			// 6. execute all tasks
-			await runParallel(tasks, globals.concurrency);
+			await runParallel(tasks, globals.concurrency, globals.preserveOrder);
 
 			timer.stop();
 
diff --git a/src/run-parallel.js b/src/run-parallel.js
index c49a3b6..5e698de 100644
--- a/src/run-parallel.js
+++ b/src/run-parallel.js
@@ -2,7 +2,7 @@ const Semaphore = require('async-sema');
 const logger = require('./logger');
 const EventedQueue = require('./evented-queue');
 
-module.exports = (tasks = [], concurrency = 1) => {
+module.exports = (tasks = [], concurrency = 1, preserveOrder = false) => {
 	const semaphore = new Semaphore(concurrency);
 	const queue = new EventedQueue();
 
@@ -10,13 +10,13 @@ module.exports = (tasks = [], concurrency = 1) => {
 
 	return Promise.all(
 		tasks.map(({ pkg, apply }) => {
+			queue.add(pkg.name);
+
 			return semaphore
 				.acquire()
 				.then(() => {
-					// Queue the package now to maintain running order...
-					queue.add(pkg.name);
-					// ...but wait for any dependencies in the queue to finish
-					return queue.waitFor(pkg.allDependencies);
+					// wait for any dependencies still in the queue to finish
+					return preserveOrder ? queue.waitFor(pkg.allDependencies) : null;
 				})
 				.then(() => {
 					return apply();