fix: swallow more require errors from *ts files (#5498)

Co-authored-by: Josh Goldberg ✨ <git@joshuakgoldberg.com>

Author: mark-wiemer

.github/DEVELOPMENT.md

@@ -16,3 +16,11 @@ If you are having trouble, don't be afraid to [ask for help](./CONTRIBUTING.md#
    - Do not use `yarn install` or `pnpm install`.
    - Some optional dependencies may fail; you can safely ignore these unless you are trying to build the documentation.
    - If you're sick of seeing the failures, run `npm install --ignore-scripts`.
+
+## Tests
+
+Running tests via `npm test` should work on any operating system with any supported version of Node. If they don't, please file an issue or contact us in [our Discord](https://discord.gg/KeDn2uXhER).
+
+Running tests this way runs all tests in a "covered" state. That is, they're run through Istanbul's `nyc` command. This pre-loads some modules for coverage reporting and can change the behavior in niche situations around Node's loader system.
+
+Tests with `@bare` in their name should also be run in an uncovered or "bare" state, that is, directly through `node bin/mocha.js` and not through `nyc`. `npm test` and our CI handles this with `test-node-integration:bare`. See [issue 5361 (comment)](https://github.com/mochajs/mocha/issues/5361#issuecomment-3368708708) for details.

.github/workflows/mocha.yml

@@ -37,6 +37,7 @@ jobs:
           - interfaces
           - unit
           - integration
+          - integration:bare
           - jsapi
           - requires
           - reporters
@@ -63,6 +64,8 @@ jobs:
         include:
           - test-part: jsapi
             coverage: false
+          - test-part: integration:bare
+            coverage: false
     with:
       os: 'ubuntu-latest,windows-latest'
       # We pin exact versions here per https://github.com/mochajs/mocha/issues/5052

lib/nodejs/esm-utils.js

@@ -106,7 +106,7 @@ const requireModule = async (file, esmDecorator) => {
       // What we actually care about is the original require() error.
       // See: https://github.com/mochajs/mocha/issues/5393
       if (
-        /\.(cts|mts|ts)$/.test(file) ||
+        /\.(cts|mts|ts)$/.test(file) &&
         importErr.code === 'ERR_UNKNOWN_FILE_EXTENSION'
       ) {
         throw requireErr;

package.json

@@ -73,7 +73,9 @@
     "test-coverage-generate": "nyc report --reporter=lcov --reporter=text",
     "test-node-run-only": "nyc --no-clean --reporter=json node bin/mocha.js",
     "test-node-run": "nyc --no-clean --reporter=json node bin/mocha.js --forbid-only",
+    "test-node-run:bare": "node bin/mocha.js --grep @bare",
     "test-node:integration": "run-s clean build && npm run -s test-node-run -- --parallel --timeout 10000 --slow 3750 \"test/integration/**/*.spec.js\"",
+    "test-node:integration:bare": "run-s clean build && npm run -s test-node-run:bare -- --parallel --timeout 10000 --slow 3750 \"test/integration/**/*.spec.js\"",
     "test-node:integration:watch": "run-s clean build && npm run -s test-node-run -- --parallel --timeout 10000 --slow 3750 \"test/integration/options/watch.spec.js\"",
     "test-node:interfaces:bdd": "npm run -s test-node-run -- --ui bdd test/interfaces/bdd.spec",
     "test-node:interfaces:exports": "npm run -s test-node-run -- --ui exports test/interfaces/exports.spec",

test/integration/esm.spec.js

@@ -82,7 +82,7 @@ describe('esm', function () {
     );
   });
 
-  it('should throw an ERR_MODULE_NOT_FOUND and not ERR_REQUIRE_ESM if file imports a non-existing module with a loader', async function () {
+  it('should throw an ERR_MODULE_NOT_FOUND and not ERR_REQUIRE_ESM if file imports a non-existing module with a loader @bare', async function () {
     const fixture =
       'esm/loader-with-module-not-found/test-that-imports-non-existing-module.fixture.ts';