test(linter/plugins): include stack trace in plugin loading errors

apps/oxlint/src-js/plugins/utils.ts

@@ -3,18 +3,28 @@
  *
  * `err` is expected to be an `Error` object, but can be anything.
  *
- * This function will never throw, and always returns a string, even if:
+ * * If it's an `Error`, the error message and stack trace is returned.
+ * * If it's another object with a string `message` property, `message` is returned.
+ * * Otherwise, a generic "Unknown error" message is returned.
+ *
+ * This function will never throw, and always returns a non-empty string, even if:
  *
  * * `err` is `null` or `undefined`.
  * * `err` is an object with a getter for `message` property which throws.
- * * `err` has a getter for `message` property which returns a different value each time it's accessed.
+ * * `err` has a getter for `stack` or `message` property which returns a different value each time it's accessed.
  *
  * @param err - Error
  * @returns Error message
  */
 export function getErrorMessage(err: unknown): string {
   try {
-    const { message } = err as undefined | { message: string };
+    if (err instanceof Error) {
+      // Note: `stack` includes the error message
+      const { stack } = err;
+      if (typeof stack === 'string' && stack !== '') return stack;
+    }
+
+    const { message } = err as { message?: unknown };
     if (typeof message === 'string' && message !== '') return message;
   } catch {}
 

apps/oxlint/test/__snapshots__/e2e.test.ts.snap

@@ -444,18 +444,27 @@ exports[`oxlint CLI > should report an error if a a rule is not found within a c
 "
 `;
 
-exports[`oxlint CLI > should report an error if a custom plugin cannot be loaded 1`] = `
+exports[`oxlint CLI > should report an error if a custom plugin in config but JS plugins are not enabled 1`] = `
+"Failed to parse configuration file.
+
+  x JS plugins are not supported without \`--experimental-js-plugins\` CLI option
+"
+`;
+
+exports[`oxlint CLI > should report an error if a custom plugin is missing 1`] = `
 "Failed to parse configuration file.
 
   x Failed to load JS plugin: ./test_plugin
   |   Cannot find module './test_plugin'
 "
 `;
 
-exports[`oxlint CLI > should report an error if a custom plugin in config but JS plugins are not enabled 1`] = `
+exports[`oxlint CLI > should report an error if a custom plugin throws an error during import 1`] = `
 "Failed to parse configuration file.
 
-  x JS plugins are not supported without \`--experimental-js-plugins\` CLI option
+  x Failed to load JS plugin: ./test_plugin
+  |   Error: whoops!
+  |     at <root>/apps/oxlint/test/fixtures/custom_plugin_import_error/test_plugin/index.js:1:7
 "
 `;
 

apps/oxlint/test/e2e.test.ts

@@ -6,6 +6,8 @@ import { execa } from 'execa';
 
 const PACKAGE_ROOT_PATH = dirname(import.meta.dirname);
 const CLI_PATH = pathJoin(PACKAGE_ROOT_PATH, 'dist/cli.js');
+const ROOT_URL = new URL('../../../', import.meta.url).href;
+const FIXTURES_URL = new URL('./fixtures/', import.meta.url).href;
 
 async function runOxlintWithoutPlugins(cwd: string, args: string[] = []) {
   return await execa('node', [CLI_PATH, ...args], {
@@ -19,9 +21,28 @@ async function runOxlint(cwd: string, args: string[] = []) {
 }
 
 function normalizeOutput(output: string): string {
-  return output
-    .replace(/Finished in \d+(\.\d+)?(s|ms|us|ns)/, 'Finished in Xms')
-    .replace(/using \d+ threads./, 'using X threads.');
+  let lines = output.split('\n');
+
+  // Remove timing and thread count info which can vary between runs
+  lines[lines.length - 1] = lines[lines.length - 1].replace(
+    /^Finished in \d+(?:\.\d+)?(?:s|ms|us|ns) on (\d+) file(s?) using \d+ threads.$/,
+    'Finished in Xms on $1 file$2 using X threads.',
+  );
+
+  // Remove lines from stack traces which are outside `fixtures` directory.
+  // Replace path to repo root in stack traces with `<root>`.
+  lines = lines.flatMap((line) => {
+    // e.g. ` | at file:///path/to/oxc/apps/oxlint/test/fixtures/foor/bar.js:1:1`
+    // e.g. ` | at whatever (file:///path/to/oxc/apps/oxlint/test/fixtures/foor/bar.js:1:1)`
+    const match = line.match(/^(\s*\|\s+at (?:.+?\()?)(.+)$/);
+    if (match) {
+      const [, premable, at] = match;
+      return at.startsWith(FIXTURES_URL) ? [`${premable}<root>/${at.slice(ROOT_URL.length)}`] : [];
+    }
+    return [line];
+  });
+
+  return lines.join('\n');
 }
 
 describe('oxlint CLI', () => {
@@ -73,12 +94,18 @@ describe('oxlint CLI', () => {
     expect(normalizeOutput(stdout)).toMatchSnapshot();
   });
 
-  it('should report an error if a custom plugin cannot be loaded', async () => {
+  it('should report an error if a custom plugin is missing', async () => {
     const { stdout, exitCode } = await runOxlint('test/fixtures/missing_custom_plugin');
     expect(exitCode).toBe(1);
     expect(normalizeOutput(stdout)).toMatchSnapshot();
   });
 
+  it('should report an error if a custom plugin throws an error during import', async () => {
+    const { stdout, exitCode } = await runOxlint('test/fixtures/custom_plugin_import_error');
+    expect(exitCode).toBe(1);
+    expect(normalizeOutput(stdout)).toMatchSnapshot();
+  });
+
   it('should report an error if a rule is not found within a custom plugin', async () => {
     const { stdout, exitCode } = await runOxlint('test/fixtures/custom_plugin_missing_rule');
     expect(exitCode).toBe(1);

apps/oxlint/test/fixtures/custom_plugin_import_error/.oxlintrc.json

@@ -0,0 +1,7 @@
+{
+  "plugins": ["./test_plugin"],
+  "categories": { "correctness": "off" },
+  "rules": {
+    "basic-custom-plugin/unknown-rule": "error"
+  }
+}

apps/oxlint/test/fixtures/custom_plugin_import_error/test_plugin/index.js

@@ -0,0 +1 @@
+throw new Error("whoops!");