build: refuse unknown arguments; name the fix when typescript is missing

Two failures of scripts/build.mjs did not say what to change. `node scripts/build.mjs --outt /some/dir` ignored
the misspelt flag, exited 0 and replaced the tracked dist/. Without devDependencies (npm install --omit=dev in a
clone runs "prepare") the script died with a stack trace, because typescript was resolved at module level,
outside the try block.

The script now takes no arguments or `--out <dir>` and answers anything else with one line and the usage, exit 1.
A missing compiler gives "build: typescript is not installed: run npm install (it is a devDependency)". The body
moved into build(args), so the staging directory and the compiler path are no longer module-level variables.

Two tests on a temporary package: three refused argument lists, and a package without node_modules; both compare
the package before and after. No change to dist/. npm test: 30 pass in 9.5-10.2 s (load average 7 on 4 cores).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
This commit is contained in:
David 2026-09-28 14:42:33 +00:00
parent ee311dab01
commit d96c6b8372
2 changed files with 71 additions and 27 deletions

View file

@ -14,42 +14,59 @@ import { createRequire } from "node:module";
import { basename, dirname, join, resolve } from "node:path";
import { fileURLToPath } from "node:url";
const USAGE = "usage: node scripts/build.mjs [--out <dir>]";
const root = resolve(dirname(fileURLToPath(import.meta.url)), "..");
const tsc = createRequire(import.meta.url).resolve("typescript/bin/tsc");
function outputDirectory(args) {
const at = args.indexOf("--out");
if (at === -1) return join(root, "dist");
if (!args[at + 1]) throw new Error("--out needs a directory");
return resolve(args[at + 1]);
if (args.length === 0) return join(root, "dist");
const [flag, dir, ...rest] = args;
// A misspelt --out must not fall back to the default and replace the tracked dist/
if (flag !== "--out") throw new Error(`unknown argument ${flag}; ${USAGE}`);
if (!dir) throw new Error(`--out needs a directory; ${USAGE}`);
if (rest.length > 0) throw new Error(`unknown argument ${rest[0]}; ${USAGE}`);
return resolve(dir);
}
function compile(project, options) {
const run = spawnSync(process.execPath, [tsc, "-p", join(root, project), ...options], { cwd: root, stdio: "inherit" });
if (run.error) throw run.error;
if (run.status !== 0) throw new Error(`tsc -p ${project} failed, ${out} is unchanged`);
function compiler() {
try {
return createRequire(import.meta.url).resolve("typescript/bin/tsc");
} catch (err) {
if (err.code !== "MODULE_NOT_FOUND") throw err;
throw new Error("typescript is not installed: run npm install (it is a devDependency)");
}
}
let out;
let staging;
try {
out = outputDirectory(process.argv.slice(2));
function build(args) {
const out = outputDirectory(args);
const tsc = compiler();
// Beside the output, not in it: the package ships all of dist/, and a build that is killed cannot remove its
// staging directory - the next build does. Same parent directory, so the renames below stay on one filesystem.
staging = join(dirname(out), `.${basename(out)}-staging`);
const staging = join(dirname(out), `.${basename(out)}-staging`);
const compile = (project, options) => {
const run = spawnSync(process.execPath, [tsc, "-p", join(root, project), ...options], { cwd: root, stdio: "inherit" });
if (run.error) throw run.error;
if (run.status !== 0) throw new Error(`tsc -p ${project} failed, ${out} is unchanged`);
};
rmSync(staging, { recursive: true, force: true });
compile("tsconfig.cjs.json", ["--outDir", join(staging, "cjs"), "--declarationDir", join(staging, "types")]);
compile("tsconfig.esm.json", ["--outDir", join(staging, "esm")]);
// The package is "type": "commonjs"; this marks the .js files under esm/ as ES modules.
writeFileSync(join(staging, "esm", "package.json"), JSON.stringify({ type: "module" }, null, 2) + "\n");
mkdirSync(out, { recursive: true });
for (const part of ["cjs", "esm", "types"]) {
rmSync(join(out, part), { recursive: true, force: true });
renameSync(join(staging, part), join(out, part));
try {
compile("tsconfig.cjs.json", ["--outDir", join(staging, "cjs"), "--declarationDir", join(staging, "types")]);
compile("tsconfig.esm.json", ["--outDir", join(staging, "esm")]);
// The package is "type": "commonjs"; this marks the .js files under esm/ as ES modules.
writeFileSync(join(staging, "esm", "package.json"), JSON.stringify({ type: "module" }, null, 2) + "\n");
mkdirSync(out, { recursive: true });
for (const part of ["cjs", "esm", "types"]) {
rmSync(join(out, part), { recursive: true, force: true });
renameSync(join(staging, part), join(out, part));
}
} finally {
rmSync(staging, { recursive: true, force: true });
}
}
try {
build(process.argv.slice(2));
} catch (err) {
console.error(`build: ${err.message}`);
process.exitCode = 1;
} finally {
if (staging) rmSync(staging, { recursive: true, force: true });
}

View file

@ -11,8 +11,8 @@ const { spawnSync } = require("node:child_process");
const ROOT = path.join(__dirname, "..");
// A package directory with the build script, the three tsconfig files, src/index.ts and the dist/ of an earlier
// build; removed when the test ends.
function scratchPackage(t, source) {
// build; removed when the test ends. installed: false leaves node_modules out, as before npm install.
function scratchPackage(t, source, { installed = true } = {}) {
const dir = fs.mkdtempSync(path.join(os.tmpdir(), "alex2node-build-"));
t.after(() => fs.rmSync(dir, { recursive: true, force: true }));
for (const file of ["scripts/build.mjs", "tsconfig.json", "tsconfig.cjs.json", "tsconfig.esm.json", "src/index.ts"]) {
@ -24,7 +24,7 @@ function scratchPackage(t, source) {
fs.mkdirSync(path.join(dir, "dist", part), { recursive: true });
fs.writeFileSync(path.join(dir, "dist", part, "earlier.txt"), `${part} of the earlier build\n`);
}
fs.symlinkSync(path.join(ROOT, "node_modules"), path.join(dir, "node_modules"), "dir");
if (installed) fs.symlinkSync(path.join(ROOT, "node_modules"), path.join(dir, "node_modules"), "dir");
return dir;
}
@ -82,3 +82,30 @@ test("the second compiler run fails: what the first one wrote is dropped, dist/
assert.match(run.stderr, /^build: tsc -p tsconfig\.esm\.json failed/m);
assert.deepEqual(snapshot(dir), before);
});
test("an argument the script does not know is refused: a misspelt --out must not build into dist/", (t) => {
const dir = scratchPackage(t, "export const port = 1883;\n");
const before = snapshot(dir);
const elsewhere = path.join(dir, "elsewhere");
const refused = [
[["--outt", elsewhere], "unknown argument --outt"],
[["--out"], "--out needs a directory"],
[["--out", elsewhere, "--watch"], "unknown argument --watch"],
];
for (const [args, reason] of refused) {
const run = build(dir, ...args);
assert.equal(run.status, 1, args.join(" "));
assert.equal(run.stderr, `build: ${reason}; usage: node scripts/build.mjs [--out <dir>]\n`);
assert.deepEqual(snapshot(dir), before, args.join(" "));
}
});
test("without typescript the build says what to install, in one line", (t) => {
const dir = scratchPackage(t, "export const port = 1883;\n", { installed: false });
const before = snapshot(dir);
const run = build(dir);
assert.equal(run.status, 1);
assert.equal(run.stderr, "build: typescript is not installed: run npm install (it is a devDependency)\n");
assert.deepEqual(snapshot(dir), before);
});