From 3830861a1dd720d4f798ebfb5d63c976ca629347 Mon Sep 17 00:00:00 2001
From: dbarabashh <dbarabashdev@gmail.com>
Date: Sat, 23 Aug 2025 15:53:44 +0100
Subject: [PATCH 1/2] fix(rule-tester): normalize paths before checking if they
 escape cwd

---
 packages/rule-tester/src/RuleTester.ts      |  2 +-
 packages/rule-tester/tests/filename.test.ts | 36 +++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/packages/rule-tester/src/RuleTester.ts b/packages/rule-tester/src/RuleTester.ts
index c81f7296e189..25f572952719 100644
--- a/packages/rule-tester/src/RuleTester.ts
+++ b/packages/rule-tester/src/RuleTester.ts
@@ -210,7 +210,7 @@ export class RuleTester extends TestFramework {
     // file name (`foo.ts`), don't change the base path.
     if (
       filename != null &&
-      (path.isAbsolute(filename) || filename.startsWith('..'))
+      (path.isAbsolute(filename) || path.normalize(filename).startsWith('..'))
     ) {
       basePath = path.parse(
         path.resolve(basePath ?? process.cwd(), filename),
diff --git a/packages/rule-tester/tests/filename.test.ts b/packages/rule-tester/tests/filename.test.ts
index 0e9656702e95..edbf557aae69 100644
--- a/packages/rule-tester/tests/filename.test.ts
+++ b/packages/rule-tester/tests/filename.test.ts
@@ -57,6 +57,24 @@ describe('rule tester filename', () => {
         errors: [{ messageId: 'foo' }],
         filename: '../foo.js',
       },
+      {
+        name: 'non-normalized relative path starting with ./',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: './../../escaped/cwd/file.ts',
+      },
+      {
+        name: 'non-normalized relative path ./../',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: './../foo.js',
+      },
+      {
+        name: 'non-normalized relative path with multiple ./',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: '././../foo.js',
+      },
     ],
     valid: [],
   });
@@ -81,6 +99,24 @@ describe('rule tester filename', () => {
         errors: [{ messageId: 'foo' }],
         filename: '../foo.js',
       },
+      {
+        name: 'non-normalized relative path starting with ./',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: './../../escaped/cwd/file.ts',
+      },
+      {
+        name: 'non-normalized relative path ./../',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: './../foo.js',
+      },
+      {
+        name: 'non-normalized relative path with multiple ./',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: '././../foo.js',
+      },
     ],
     valid: [],
   });

From 6ff0c5a37043ea9609adfe2db932234084a816cf Mon Sep 17 00:00:00 2001
From: dbarabashh <dbarabashdev@gmail.com>
Date: Thu, 28 Aug 2025 20:34:27 +0100
Subject: [PATCH 2/2] added test cases

---
 packages/rule-tester/tests/filename.test.ts | 36 +++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/packages/rule-tester/tests/filename.test.ts b/packages/rule-tester/tests/filename.test.ts
index edbf557aae69..8f3442cf670a 100644
--- a/packages/rule-tester/tests/filename.test.ts
+++ b/packages/rule-tester/tests/filename.test.ts
@@ -75,6 +75,24 @@ describe('rule tester filename', () => {
         errors: [{ messageId: 'foo' }],
         filename: '././../foo.js',
       },
+      {
+        name: 'non-normalized path a/../../',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: 'a/../../file.ts',
+      },
+      {
+        name: 'non-normalized path a/b/../c',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: 'a/b/../c',
+      },
+      {
+        name: 'non-normalized path with multiple slashes',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: 'a/////////////../../../b',
+      },
     ],
     valid: [],
   });
@@ -117,6 +135,24 @@ describe('rule tester filename', () => {
         errors: [{ messageId: 'foo' }],
         filename: '././../foo.js',
       },
+      {
+        name: 'non-normalized path a/../../',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: 'a/../../file.ts',
+      },
+      {
+        name: 'non-normalized path a/b/../c',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: 'a/b/../c',
+      },
+      {
+        name: 'non-normalized path with multiple slashes',
+        code: '_',
+        errors: [{ messageId: 'foo' }],
+        filename: 'a/////////////../../../b',
+      },
     ],
     valid: [],
   });