changeset-validate.mjs

/* eslint-disable no-console */
import fs from "node:fs/promises";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { simpleGit } from "simple-git";

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const rootPath = path.join(__dirname, "..");
const git = simpleGit(rootPath);

const pkgJson = JSON.parse(
  await fs.readFile(path.join(rootPath, "package.json"), "utf8"),
);

const VALID_BUMPS = new Set(["major", "minor", "patch"]);
const FRONTMATTER_RE = /^---\r?\n([\s\S]*?)\r?\n---(?:\r?\n|$)/;
const ENTRY_RE = /^"([^"]+)"\s*:\s*([a-zA-Z]+)\s*$/;

const toLines = (output) =>
  output
    .split(/\r?\n/)
    .map((line) => line.trim())
    .filter(Boolean);

const isChangeset = (filePath) => {
  const normalized = filePath.replaceAll("\\", "/");
  return (
    normalized.startsWith(".changeset/") &&
    normalized.endsWith(".md") &&
    normalized !== ".changeset/README.md"
  );
};

const gitDiff = async (more = []) => {
  const args = [
    "diff",
    "--name-only",
    // cspell:ignore ACMR
    "--diff-filter=ACMR",
    ...more,
    "--",
    ".changeset/*.md",
  ].filter(Boolean);

  return toLines(await git.raw(args));
};

const getChangedFiles = async () => {
  const files = new Set();
  const baseRef = process.env.GITHUB_BASE_REF;

  // GitHub Actions base diff
  if (baseRef) {
    for (const file of await gitDiff([`origin/${baseRef}...HEAD`])) {
      if (isChangeset(file)) files.add(file);
    }
  }
  // Local working tree changes
  else {
    const _files = [
      // Unstaged changes
      ...(await gitDiff()),
      // Staged but uncommitted changes
      ...(await gitDiff(["--cached"])),
      // Untracked files
      ...(await git.status()).not_added,
    ];
    for (const file of _files) {
      if (isChangeset(file)) files.add(file);
    }
  }
  return files;
};

const validate = async (filePath) => {
  const absoluteFilePath = path.join(rootPath, filePath);
  const content = await fs.readFile(absoluteFilePath, "utf8");
  const frontmatterMatch = content.match(FRONTMATTER_RE);
  const errors = [];

  if (!frontmatterMatch) {
    errors.push("missing YAML frontmatter block");
    return errors;
  }

  const entries = frontmatterMatch[1]
    .split(/\r?\n/)
    .map((line) => line.trim())
    .filter(Boolean);

  if (entries.length === 0) {
    errors.push("frontmatter does not contain package bump entries");
    return errors;
  }

  for (const entry of entries) {
    const match = entry.match(ENTRY_RE);
    if (!match) {
      errors.push(`invalid frontmatter entry: ${entry}`);
      continue;
    }

    const [, pkgName, bumpType] = match;
    if (pkgName !== pkgJson.name) {
      errors.push(
        `invalid package name "${pkgName}", expected "${pkgJson.name}"`,
      );
    }

    if (!VALID_BUMPS.has(bumpType)) {
      errors.push(
        `invalid bump type "${bumpType}", expected one of: major, minor, patch`,
      );
    }
  }

  return errors;
};

const changedFiles = await getChangedFiles();

if (changedFiles.size === 0) {
  console.log("No changed changeset files found.");
} else {
  const failures = [];
  for (const filePath of changedFiles) {
    const errors = await validate(filePath);
    for (const error of errors) {
      failures.push(`${filePath}: ${error}`);
    }
  }

  if (failures.length > 0) {
    console.error("Changeset validation failed:");
    for (const failure of failures) {
      console.error(`- ${failure}`);
    }
    process.exitCode = 1;
  }
}