thelounge/scripts/changelog.js

/*
This (very The Lounge-custom) script is a helper to generate changelog entries.

Note that it is not meant to produce fully-automated changelogs like other tools
do, but merely prepare a changelog entry without risks of mistyping a URL or
missing a contribution: changelogs are meant for humans, and therefore must be
manually curated as such, with ❤️.

## Set up:

- Create a personal access token with `public_repo` at
  https://github.com/settings/tokens. Make sure to write it down as you will not
  be able to display it again.

- Use Node.js v8+:

  ```sh
  nvm install 8
  ```

## Usage

npm v5 removes packages not listed in package.json when running `npm install` so
it is very likely you will have to run all those each time:

```sh
 export CHANGELOG_TOKEN=<The personal access token created on GitHub above>
node scripts/changelog <version>
```

`<version>` must be either:

- A keyword among: major, minor, patch, prerelease, pre
- An explicit version of either format:
  - `MAJOR.MINOR.PATCH` for a stable release, for example `2.5.0`
  - `MAJOR.MINOR.PATCH-(pre|rc).N` for a pre-release, for example `2.5.0-rc.1`

## TODOs:

- Use better labels for better categorization
- Add some stats to the git commit (how many LOCs total / in this release, etc.)
- This script requires Node v8, but `npm version` currently fails with Node v8
  as we gitignore package-lock.json (how is that even a thing?!).
*/

"use strict";

const _ = require("lodash");
const colors = require("colors/safe");
const fs = require("fs");
const GraphQLClient = require("graphql-request").GraphQLClient;
const moment = require("moment");
const semver = require("semver");
const util = require("util");
const log = require("../src/log");
const packageJson = require("../package.json");
const token = process.env.CHANGELOG_TOKEN;

const readFile = util.promisify(fs.readFile);
const writeFile = util.promisify(fs.writeFile);

// CLI argument validations

if (token === undefined) {
	log.error(`Environment variable ${colors.bold("CHANGELOG_TOKEN")} must be set.`);
	process.exit(1);
}

if (process.argv[2] === undefined) {
	log.error(`Argument ${colors.bold("version")} is missing`);
	process.exit(1);
}

// If version is not a valid X.Y.Z, it may be something like "pre".
let version = semver.valid(process.argv[2]);

if (!version) {
	version = semver.inc(packageJson.version, process.argv[2]);
}

if (!/^[0-9]+\.[0-9]+\.[0-9]+(-(pre|rc)+\.[0-9]+)?$/.test(version)) {
	log.error(`Argument ${colors.bold("version")} is incorrect It must be either:`);
	log.error(`- A keyword among: ${colors.green("major")}, ${colors.green("minor")}, ${colors.green("patch")}, ${colors.green("prerelease")}, ${colors.green("pre")}`);
	log.error(`- An explicit version of format ${colors.green("x.y.z")} (stable) or ${colors.green("x.y.z-(pre|rc).n")} (pre-release).`);
	process.exit(1);
}

// Templates

function prereleaseTemplate(items) {
	return `
## v${items.version} - ${items.date} [Pre-release]

[See the full changelog](${items.fullChangelogUrl})

${prereleaseType(items.version) === "rc" ?
		`This is a release candidate (RC) for v${stableVersion(items.version)} to ensure maximum stability for public release.
Bugs may be fixed, but no further features will be added until the next stable version.` :

		`This is a pre-release for v${stableVersion(items.version)} to offer latest changes without having to wait for a stable release.
 At this stage, features may still be added or modified until the first release candidate for this version gets released.`
}

Please refer to the commit list given above for a complete list of changes, or wait for the stable release to get a thoroughly prepared change log entry.

As with all pre-releases, this version requires explicit use of the \`next\` tag to be installed:

\`\`\`sh
npm install -g thelounge@next
\`\`\`
`;
}

function stableTemplate(items) {
	return `
## v${items.version} - ${items.date}

For more details, [see the full changelog](${items.fullChangelogUrl}) and [milestone](${items.milestone.url}?closed=1).

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@ DESCRIPTION, ANNOUNCEMENT, ETC. @@
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

### Added

### Changed

${_.isEmpty(items.dependencies) ? "" :
		`- Update production dependencies to their latest versions, by [Greenkeeper](https://greenkeeper.io/) 🚀:
${printDependencyList(items.dependencies)}`
}

### Deprecated

${printList(items.deprecations)}

### Removed

### Fixed

### Security

${printList(items.security)}

### Documentation

${_.isEmpty(items.documentation) ? "" :
		`In the main repository:

${printList(items.documentation)}`
}

${_.isEmpty(items.websiteDocumentation) ? "" :
		`On the [website repository](https://github.com/thelounge/thelounge.github.io):

${printList(items.websiteDocumentation)}`
}

### Internals

${printList(items.internals)}${
	_.isEmpty(items.devDependencies) ? "" : `
- Update development dependencies to their latest versions, by [Greenkeeper](https://greenkeeper.io/) 🚀:
${printDependencyList(items.devDependencies)}`}

@@@@@@@@@@@@@@@@@@@
@@ UNCATEGORIZED @@
@@@@@@@@@@@@@@@@@@@

${printList(items.uncategorized)}
`;
}

// Returns true if the given version is a pre-release (i.e. 2.0.0-pre.3,
// 2.5.0-rc.1, etc.), or false otherwise
function isPrerelease(v) {
	return v.includes("-");
}

// Given a version of `x.y.z-abc.n`, returns `abc`, i.e. the type of pre-release
function prereleaseType(v) {
	return semver.prerelease(v)[0];
}

// Returns the stable version that this pre-release version is targeting. For
// example, if new version is 2.5.0-rc.2, next stable version will be 2.5.0.
function stableVersion(prereleaseVersion) {
	return prereleaseVersion.substr(0, prereleaseVersion.indexOf("-"));
}

// Generates a compare-view URL between 2 versions of The Lounge
function fullChangelogUrl(v1, v2) {
	return `https://github.com/thelounge/lounge/compare/v${v1}...v${v2}`;
}

// This class is a facade to fetching details about commits / PRs / tags / etc.
// for a given repository of our organization.
class RepositoryFetcher {
	// Holds a GraphQLClient and the name of the repository within the
	// organization https://github.com/thelounge.
	constructor(graphqlClient, repositoryName) {
		this.graphqlClient = graphqlClient;
		this.repositoryName = repositoryName;
	}

	// Base function that actually makes the GraphQL API call
	async fetch(query, variables = {}) {
		return this.graphqlClient.request(
			query,
			Object.assign(variables, {repositoryName: this.repositoryName})
		);
	}

	// Returns the git commit that is attached to a given tag
	async fetchTaggedCommit(tag) {
		const tagQuery = `query fetchTaggedCommit($repositoryName: String!, $tag: String!) {
			repository(owner: "thelounge", name: $repositoryName) {
				ref(qualifiedName: $tag) {
					tag: target {
						... on Tag {
							commit: target {
								oid
							}
						}
					}
				}
			}
		}`;
		const data = await this.fetch(tagQuery, {tag});
		return data.repository.ref.tag.commit;
	}

	// Returns an array of annotated commits that have been made on the master
	// branch since a given version. Each commit is an object that can optionally
	// have a `pullRequestId` if this is a merge-PR commit.
	async fetchCommitsSince(stopCommit) {
		const commitsQuery = `query fetchCommits($repositoryName: String!, $afterCursor: String) {
			repository(owner: "thelounge", name: $repositoryName) {
				ref(qualifiedName: "master") {
					target {
						... on Commit {
							history(first: 100, after: $afterCursor) {
								pageInfo {
									hasNextPage
									endCursor
								}
								commits: nodes {
									oid
									abbreviatedOid
									messageHeadline
									url
									author {
										user {
											login
											url
										}
									}
									comments(first: 100) {
										nodes {
											body
											authorAssociation
										}
									}
								}
							}
						}
					}
				}
			}
		}`;

		// Recursive function that retrieves commits page after page until the last
		// page or a given commit are reached.
		const fetchPaginatedCommits = async (afterCursor = null) => {
			const data = await this.fetch(commitsQuery, {afterCursor});
			const {commits, pageInfo} = data.repository.ref.target.history;

			if (commits.map(({oid}) => oid).includes(stopCommit.oid)) {
				return _.takeWhile(commits, ({oid}) => oid !== stopCommit.oid);
			} else if (pageInfo.hasNextPage) {
				return commits.concat(await fetchPaginatedCommits(stopCommit, pageInfo.endCursor));
			}

			return commits;
		};

		const commits = await fetchPaginatedCommits();

		commits.forEach((commit) => {
			commit.author = commit.author.user;

			const resultPR = /^Merge pull request #([0-9]+) .+/.exec(commit.messageHeadline);

			if (resultPR) {
				commit.pullRequestId = parseInt(resultPR[1], 10);
			}
		});

		return commits.reverse();
	}

	// Returns the last version prior to this new one. If new version is stable,
	// the previous one will be stable as well (all pre-release versions will be
	// skipped).
	async fetchPreviousVersion(newVersion) {
		const lastTagsQuery = `query fetchPreviousVersion($repositoryName: String!) {
			repository(owner: "thelounge", name: $repositoryName) {
				refs(refPrefix: "refs/tags/", first: 20, direction: DESC) {
					tags: nodes {
						name
					}
				}
			}
		}`;
		const data = await this.fetch(lastTagsQuery);
		const tags = data.repository.refs.tags;
		let tag;

		if (isPrerelease(newVersion)) {
			tag = tags[0];
		} else {
			tag = tags.find(({name}) => !isPrerelease(name));
		}

		return tag.name.substr(1);
	}

	// Returns information on a milestone associated to a version (i.e. not a
	// tag!) of the repository
	async fetchMilestone(targetVersion) {
		const milestonesQuery = `query fetchMilestone($repositoryName: String!) {
			repository(owner: "thelounge", name: $repositoryName) {
				milestones(last: 20) {
					nodes {
						title
						url
					}
				}
			}
		}`;
		const data = await this.fetch(milestonesQuery);
		return data.repository.milestones.nodes.find(({title}) => title === targetVersion);
	}

	// Given a list of PR numbers, retrieve information for all those PRs. They
	// are returned as a hash whose keys are `PR<number>`.
	// This is a bit wonky (generating a dynamic GraphQL query) but the GitHub API
	// does not have a way to retrieve multiple PRs given a list of IDs.
	async fetchPullRequests(numbers) {
		if (numbers.length === 0) {
			return [];
		}

		const prQuery = `query fetchPullRequests($repositoryName: String!) {
			repository(owner: "thelounge", name: $repositoryName) {
				${numbers.map((number) => `
					PR${number}: pullRequest(number: ${number}) {
						title
						url
						author {
							login
							url
						}
						labels(first: 20) {
							nodes {
								name
							}
						}
						commits(first: 100) {
							nodes {
								commit {
									oid
								}
							}
						}
					}
				`).join("")}
			}
		}`;
		const data = await this.fetch(prQuery);
		return data.repository;
	}

	// Chain several of the functions above together. Essentially, returns an
	// array composed of PRs, and commits that belong to no PRs, existing between
	// a given tag and master.
	async fetchCommitsAndPullRequestsSince(tag) {
		const taggedCommit = await this.fetchTaggedCommit(tag);
		const commits = await this.fetchCommitsSince(taggedCommit);
		const pullRequestIds = pullRequestNumbersInCommits(commits);
		const pullRequests = await this.fetchPullRequests(pullRequestIds);
		return combine(commits, pullRequests);
	}
}

// Given an array of annotated commits, returns an array of PR numbers, integers
function pullRequestNumbersInCommits(commits) {
	return commits.reduce((array, {pullRequestId}) => {
		if (pullRequestId) {
			array.push(pullRequestId);
		}
		return array;
	}, []);
}

// Given 2 arrays of annotated commits and pull requests, replace merge commits
// with the pull request information, and remove commits that are already part
// of a pull request.
// The goal of this function is to return an array consisting only of pull
// requests + commits that have been made to `master` directly.
function combine(allCommits, allPullRequests) {
	const commitsFromPRs = _.flatMap(allPullRequests, ({commits}) =>
		commits.nodes.map(({commit}) => commit.oid)
	);

	return allCommits.reduce((array, commit) => {
		if (commit.pullRequestId) {
			const pullRequest = allPullRequests[`PR${commit.pullRequestId}`];
			pullRequest.number = commit.pullRequestId;
			array.push(pullRequest);
		} else if (!commitsFromPRs.includes(commit.oid)) {
			array.push(commit);
		}

		return array;
	}, []);
}

// Builds a Markdown link for a given pull request object
function printPullRequestLink({number, url}) {
	return `[#${number}](${url})`;
}

// Builds a Markdown link for a given author object
function printAuthorLink({login, url}) {
	return `by [@${login}](${url})`;
}

// Builds a Markdown entry list item depending on its type
function printLine(entry) {
	if (entry.title) {
		return printPullRequest(entry);
	}
	return printCommit(entry);
}

// Builds a Markdown list item for a given pull request
function printPullRequest(pullRequest) {
	return `- ${pullRequest.title} (${printPullRequestLink(pullRequest)} ${printAuthorLink(pullRequest.author)})`;
}

// Builds a Markdown list item for a commit made directly in `master`
function printCommit({abbreviatedOid, messageHeadline, url, author}) {
	return `- ${messageHeadline} ([\`${abbreviatedOid}\`](${url}) ${printAuthorLink(author)})`;
}

// Builds a Markdown list of all given items
function printList(items) {
	return items.map((item) => printLine(item)).join("\n");
}

// Given a "dependencies object" (i.e. keys are package names, values are arrays
// of pull request numbers), builds a Markdown list of URLs
function printDependencyList(dependencies) {
	return _.map(dependencies, (pullRequests, name) =>
		`  - \`${name}\` (${pullRequests.map(printPullRequestLink).join(", ")})`
	).join("\n");
}

const dependencies = Object.keys(packageJson.dependencies);
const devDependencies = Object.keys(packageJson.devDependencies);

// Returns the package.json section in which that package exists, or undefined
// if that package is not listed there.
function whichDependencyType(packageName) {
	if (dependencies.includes(packageName)) {
		return "dependencies";
	} else if (devDependencies.includes(packageName)) {
		return "devDependencies";
	}
}

function hasLabelOrAnnotatedComment({labels, comments}, expected) {
	return hasLabel(labels, expected) || hasAnnotatedComment(comments, expected);
}

// Returns true if a label exists amongst a list of labels
function hasLabel(labels, expected) {
	return labels && labels.nodes.some(({name}) => name === expected);
}

function hasAnnotatedComment(comments, expected) {
	return comments && comments.nodes.some(({authorAssociation, body}) =>
		["OWNER", "MEMBER"].includes(authorAssociation) &&
		body.split("\n").includes(`[${expected}]`)
	);
}

function isSkipped(entry) {
	return hasLabelOrAnnotatedComment(entry, "Meta: Skip Changelog");
}

// Greenkeeper PRs are listed in a special, more concise way in the changelog.
// Returns true if the PR was open by Greenkeeper, false otherwise.
function isDependency({author, labels}) {
	return hasLabel(labels, "greenkeeper") || author.login === "greenkeeper";
}

function isDocumentation({labels}) {
	return hasLabel(labels, "Type: Documentation");
}

function isSecurity({labels}) {
	return hasLabel(labels, "Type: Security");
}

function isDeprecation({labels}) {
	return hasLabel(labels, "Type: Deprecation");
}

function isInternal(entry) {
	return hasLabelOrAnnotatedComment(entry, "Meta: Internal");
}

// Examples:
//   Update webpack to the latest version
//   Update `stylelint` to v1.2.3
//   Update `express` and `ua-parser-js` to latest versions
//   Update `express`, `chai`, and `ua-parser-js` to ...
function extractPackages(title) {
	return /^Update ([\w-,`. ]+) to /.exec(title)[1]
		.replace(/`/g, "")
		.split(/, and |, | and /);
}

// Given an array of entries (PRs or commits), separates them into sections,
// based on different information that describes them.
function parse(entries) {
	return entries.reduce((result, entry) => {
		if (isSkipped(entry)) {
			result.skipped.push(entry);
		} else if (isDependency(entry)) {
			extractPackages(entry.title).forEach((packageName) => {
				const dependencyType = whichDependencyType(packageName);

				if (dependencyType) {
					if (!result[dependencyType][packageName]) {
						result[dependencyType][packageName] = [];
					}
					result[dependencyType][packageName].push(entry);
				} else {
					log.info(`${colors.bold(packageName)} was updated in ${colors.green("#" + entry.number)} then removed since last release. Skipping.`);
				}
			});
		} else if (isDocumentation(entry)) {
			result.documentation.push(entry);
		} else if (isDeprecation(entry)) {
			result.deprecations.push(entry);
		} else if (isSecurity(entry)) {
			result.security.push(entry);
		} else if (isInternal(entry)) {
			result.internals.push(entry);
		} else {
			result.uncategorized.push(entry);
		}
		return result;
	}, {
		skipped: [],
		dependencies: {},
		devDependencies: {},
		deprecations: [],
		documentation: [],
		internals: [],
		security: [],
		uncategorized: [],
		unknownDependencies: new Set(),
	});
}

// Given a list of entries (pull requests, commits), retrieves GitHub usernames
// (with format `@username`) of everyone who contributed to this version.
function extractContributors(entries) {
	const set = Object.values(entries).reduce((memo, pullRequest) => {
		if (pullRequest.author.login !== "greenkeeper") {
			memo.add("@" + pullRequest.author.login);
		}
		return memo;
	}, new Set());

	return Array.from(set)
		.sort((a, b) => a.localeCompare(b, "en", {sensitivity: "base"}));
}

const client = new GraphQLClient("https://api.github.com/graphql", {
	headers: {
		Authorization: `bearer ${token}`,
	},
});

// Main function. Given a version string (i.e. not a tag!), returns a changelog
// entry and the list of contributors, for both pre-releases and stable
// releases. Templates are located at the top of this file.
async function generateChangelogEntry(targetVersion) {
	let items = {};
	let template;
	let contributors = [];

	const codeRepo = new RepositoryFetcher(client, "lounge");
	const previousVersion = await codeRepo.fetchPreviousVersion(targetVersion);

	if (isPrerelease(targetVersion)) {
		template = prereleaseTemplate;
	} else {
		template = stableTemplate;

		const codeCommitsAndPullRequests = await codeRepo.fetchCommitsAndPullRequestsSince("v" + previousVersion);
		items = parse(codeCommitsAndPullRequests);
		items.milestone = await codeRepo.fetchMilestone(targetVersion);
		contributors = extractContributors(codeCommitsAndPullRequests);

		const websiteRepo = new RepositoryFetcher(client, "thelounge.github.io");
		items.websiteDocumentation = await websiteRepo.fetchCommitsAndPullRequestsSince("v" + previousVersion);
	}

	items.version = targetVersion;
	items.date = moment().format("YYYY-MM-DD");
	items.fullChangelogUrl = fullChangelogUrl(previousVersion, targetVersion);

	return {
		changelogEntry: template(items),
		skipped: items.skipped || [],
		contributors,
	};
}

// Write a changelog entry into the CHANGELOG.md file, right after a marker that
// indicates where entries are listed.
async function addToChangelog(newEntry) {
	const changelogPath = "./CHANGELOG.md";
	const changelogMarker = "<!-- New entries go after this line -->\n\n";

	const changelog = await readFile(changelogPath, "utf8");
	const markerPosition = changelog.indexOf(changelogMarker) + changelogMarker.length;
	const newChangelog =
		changelog.substring(0, markerPosition) +
		newEntry +
		changelog.substring(markerPosition, changelog.length);

	writeFile(changelogPath, newChangelog);
}

// Wrapping this in an Async IIFE because async/await is only supported within
// functions. ¯\_(ツ)_/¯
(async () => {
	log.info(`Generating a changelog entry for ${colors.bold("v" + version)}, please wait...`);
	const startTime = Date.now();
	let changelogEntry, skipped, contributors;

	// Step 1: Generate a changelog entry

	try {
		({changelogEntry, skipped, contributors} = await generateChangelogEntry(version));
	} catch (error) {
		if (error.response && error.response.status === 401) {
			log.error(`GitHub returned an error: ${colors.red(error.response.message)}`);
			log.error(`Make sure your personal access token is set with ${colors.bold("public_repo")} scope.`);
		} else {
			log.error(error);
		}
		process.exit(1);
	}

	// Step 2: Write that changelog entry into the CHANGELOG.md file

	try {
		await addToChangelog(`${changelogEntry.trim()}\n\n`);
	} catch (error) {
		log.error(error);
		process.exit(1);
	}

	log.info(`The generated entry was added at the top of ${colors.bold("CHANGELOG.md")}.`);

	// Step 3 (optional): Print a list of skipped entries if there are any
	if (skipped.length > 0) {
		const pad = Math.max(...skipped.map((entry) => (entry.title || entry.messageHeadline).length));
		log.warn(`${skipped.length} entries were skipped:`);
		skipped.forEach((entry) => {
			log.warn(`- ${(entry.title || entry.messageHeadline).padEnd(pad)}  ${colors.gray(entry.url)}`);
		});
	}

	// Step 4: Print out some information about what just happened to the console
	const commitCommand = `git commit -m 'Add changelog entry for v${version}' CHANGELOG.md`;
	if (isPrerelease(version)) {
		log.info(`You can now run: ${colors.bold(commitCommand)}`);
	} else {
		log.info(`Please edit ${colors.bold("CHANGELOG.md")} to your liking then run: ${colors.bold(commitCommand)}`);
	}

	log.info(`Finished in ${colors.bold(Date.now() - startTime)}ms.`);

	// Step 5 (optional): Print contributors shout out if it exists
	if (contributors.length > 0) {
		log.info(`🎉  Thanks to our ${contributors.length} contributors for this release:`);
		log.info(contributors.map((contributor) => colors.green(contributor)).join(", "));
	}
})();