typescript-eslint · kirkwaiblinger · Jul 18, 2025 · Jul 18, 2025 · Jul 18, 2025 · Jul 18, 2025
diff --git a/packages/typescript-eslint/src/getTSConfigRootDirFromStack.ts b/packages/typescript-eslint/src/getTSConfigRootDirFromStack.ts
@@ -1,15 +1,40 @@
-import { fileURLToPath } from 'node:url';
+import path from 'node:path';
 
-export function getTSConfigRootDirFromStack(stack: string): string | undefined {
-  for (const line of stack.split('\n').map(line => line.trim())) {
-    const candidate = /(\S+)eslint\.config\.(c|m)?(j|t)s/.exec(line)?.[1];
-    if (!candidate) {
+/**
+ * Infers the `tsconfigRootDir` from the current call stack, using the V8 API.
+ *
+ * See https://v8.dev/docs/stack-trace-api
+ *
+ * This API is implemented in Deno and Bun as well.
+ */
+export function getTSConfigRootDirFromStack(): string | undefined {
+  function getStack(): NodeJS.CallSite[] {
+    const stackTraceLimit = Error.stackTraceLimit;
+    Error.stackTraceLimit = Infinity;
+    const prepareStackTrace = Error.prepareStackTrace;
+    Error.prepareStackTrace = (_, structuredStackTrace) => structuredStackTrace;
+
+    const dummyObject: { stack?: NodeJS.CallSite[] } = {};
+    Error.captureStackTrace(dummyObject, getTSConfigRootDirFromStack);
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- stack is set by captureStackTrace
+    const rv = dummyObject.stack!;
+
+    Error.prepareStackTrace = prepareStackTrace;
+    Error.stackTraceLimit = stackTraceLimit;
+
+    return rv;
+  }
+
+  for (const callSite of getStack()) {
+    const stackFrameFilePath = callSite.getFileName();
+    if (!stackFrameFilePath) {
       continue;
     }
 
-    return candidate.startsWith('file://')
-      ? fileURLToPath(candidate)
-      : candidate;
+    const parsedPath = path.parse(stackFrameFilePath);
+    if (/^eslint\.config\.(c|m)?(j|t)s$/.test(parsedPath.base)) {
+      return parsedPath.dir;
+    }
   }
 
   return undefined;

diff --git a/packages/typescript-eslint/src/index.ts b/packages/typescript-eslint/src/index.ts
@@ -135,10 +135,7 @@ function createConfigsGetters<T extends object>(values: T): T {
         {
           enumerable: true,
           get: () => {
-            const candidateRootDir = getTSConfigRootDirFromStack(
-              // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-              new Error().stack!,
-            );
+            const candidateRootDir = getTSConfigRootDirFromStack();
             if (candidateRootDir) {
               addCandidateTSConfigRootDir(candidateRootDir);
             }

diff --git a/packages/typescript-eslint/tests/getTsconfigRootDirFromStack.test.ts b/packages/typescript-eslint/tests/getTsconfigRootDirFromStack.test.ts
@@ -1,54 +1,28 @@
-import path from 'node:path';
-
 import { getTSConfigRootDirFromStack } from '../src/getTSConfigRootDirFromStack';
-
-const isWindows = process.platform === 'win32';
+import * as normalFolder from './path-test-fixtures/tsconfigRootDirInference-normal/normal-folder/eslint.config.cjs';
+import * as notEslintConfig from './path-test-fixtures/tsconfigRootDirInference-not-eslint-config/not-an-eslint.config.cjs';
+import * as folderThatHasASpace from './path-test-fixtures/tsconfigRootDirInference-space/folder that has a space/eslint.config.cjs';
 
 describe(getTSConfigRootDirFromStack, () => {
-  it('returns undefined when no file path seems to be an ESLint config', () => {
-    const actual = getTSConfigRootDirFromStack(
-      [
-        `Error`,
-        ' at file:///other.config.js',
-        ' at ModuleJob.run',
-        'at async NodeHfs.walk(...)',
-      ].join('\n'),
-    );
-
-    expect(actual).toBeUndefined();
+  it('does stack analysis right for normal folder', () => {
+    expect(normalFolder.get()).toBe(normalFolder.dirname());
   });
 
-  it.runIf(!isWindows)(
-    'returns a Posix config file path when a file:// path to an ESLint config is in the stack',
-    () => {
-      const actual = getTSConfigRootDirFromStack(
-        [
-          `Error`,
-          ' at file:///path/to/file/eslint.config.js',
-          ' at ModuleJob.run',
-          'at async NodeHfs.walk(...)',
-        ].join('\n'),
-      );
-
-      expect(actual).toBe('/path/to/file/');
-    },
-  );
-
-  it.each(['cjs', 'cts', 'js', 'mjs', 'mts', 'ts'])(
-    'returns the path to the config file when its extension is %s',
-    extension => {
-      const expected = isWindows ? 'C:\\path\\to\\file\\' : '/path/to/file/';
+  it('does stack analysis right for folder that has a space', () => {
+    expect(folderThatHasASpace.get()).toBe(folderThatHasASpace.dirname());
+  });
 
-      const actual = getTSConfigRootDirFromStack(
-        [
-          `Error`,
-          ` at ${path.join(expected, `eslint.config.${extension}`)}`,
-          ' at ModuleJob.run',
-          'at async NodeHfs.walk(...)',
-        ].join('\n'),
-      );
+  it("doesn't get tricked by a file that is not an ESLint config", () => {
+    expect(notEslintConfig.get()).toBeUndefined();
+  });
 
-      expect(actual).toBe(expected);
-    },
-  );
+  it('should work in the presence of a messed up strack trace string', () => {
+    const prepareStackTrace = Error.prepareStackTrace;
+    const dummyFunction = () => {};
+    Error.prepareStackTrace = dummyFunction;
+    expect(new Error().stack).toBeUndefined();
+    expect(normalFolder.get()).toBe(normalFolder.dirname());
+    expect(Error.prepareStackTrace).toBe(dummyFunction);
+    Error.prepareStackTrace = prepareStackTrace;
+  });
 });
diff --git a/.../tests/path-test-fixtures/tsconfigRootDirInference-normal/normal-folder/eslint.config.cts b/.../tests/path-test-fixtures/tsconfigRootDirInference-normal/normal-folder/eslint.config.cts
@@ -0,0 +1,10 @@
+/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
+import { getTSConfigRootDirFromStack } from './../../../../src/getTSConfigRootDirFromStack';
+
+export function get() {
+  return getTSConfigRootDirFromStack();
+}
+
+export function dirname() {
+  return __dirname;
+}
diff --git a/...ts/path-test-fixtures/tsconfigRootDirInference-not-eslint-config/not-an-eslint.config.cts b/...ts/path-test-fixtures/tsconfigRootDirInference-not-eslint-config/not-an-eslint.config.cts
@@ -0,0 +1,10 @@
+/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
+import { getTSConfigRootDirFromStack } from '../../../src/getTSConfigRootDirFromStack';
+
+export function get() {
+  return getTSConfigRootDirFromStack();
+}
+
+export function dirname() {
+  return __dirname;
+}
diff --git a/...th-test-fixtures/tsconfigRootDirInference-space/folder that has a space/eslint.config.cts b/...th-test-fixtures/tsconfigRootDirInference-space/folder that has a space/eslint.config.cts
@@ -0,0 +1,10 @@
+/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
+import { getTSConfigRootDirFromStack } from '../../../../src/getTSConfigRootDirFromStack';
+
+export function get() {
+  return getTSConfigRootDirFromStack();
+}
+
+export function dirname() {
+  return __dirname;
+}