From 491039b9e351951b48c8d94539f820249a9f8044 Mon Sep 17 00:00:00 2001
From: CrazyMax <1951866+crazy-max@users.noreply.github.com>
Date: Thu, 4 Jul 2024 16:33:39 +0200
Subject: [PATCH] util: isPathRelativeTo func

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>
---
 __tests__/util.test.ts | 28 ++++++++++++++++++++++++++++
 src/util.ts            |  7 +++++++
 2 files changed, 35 insertions(+)

diff --git a/__tests__/util.test.ts b/__tests__/util.test.ts
index 6889c1b..2a733d9 100644
--- a/__tests__/util.test.ts
+++ b/__tests__/util.test.ts
@@ -416,6 +416,34 @@ lines`;
   });
 });
 
+describe('isPathRelativeTo', () => {
+  it('should return true for a child path directly inside the parent path', () => {
+    const parentPath = '/home/user/projects';
+    const childPath = '/home/user/projects/subproject';
+    expect(Util.isPathRelativeTo(parentPath, childPath)).toBe(true);
+  });
+  it('should return true for a deeply nested child path inside the parent path', () => {
+    const parentPath = '/home/user';
+    const childPath = '/home/user/projects/subproject/module';
+    expect(Util.isPathRelativeTo(parentPath, childPath)).toBe(true);
+  });
+  it('should return false for a child path outside the parent path', () => {
+    const parentPath = '/home/user/projects';
+    const childPath = '/home/user/otherprojects/subproject';
+    expect(Util.isPathRelativeTo(parentPath, childPath)).toBe(false);
+  });
+  it('should return true for a child path specified with relative segments', () => {
+    const parentPath = '/home/user/projects';
+    const childPath = '/home/user/projects/../projects/subproject';
+    expect(Util.isPathRelativeTo(parentPath, childPath)).toBe(true);
+  });
+  it('should return false when the child path is actually a parent path', () => {
+    const parentPath = '/home/user/projects/subproject';
+    const childPath = '/home/user/projects';
+    expect(Util.isPathRelativeTo(parentPath, childPath)).toBe(false);
+  });
+});
+
 // See: https://github.com/actions/toolkit/blob/a1b068ec31a042ff1e10a522d8fdf0b8869d53ca/packages/core/src/core.ts#L89
 function getInputName(name: string): string {
   return `INPUT_${name.replace(/ /g, '_').toUpperCase()}`;
diff --git a/src/util.ts b/src/util.ts
index 91fc2f6..2587aca 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -16,6 +16,7 @@
 
 import crypto from 'crypto';
 import fs from 'fs';
+import path from 'path';
 import * as core from '@actions/core';
 import * as io from '@actions/io';
 import {parse} from 'csv-parse/sync';
@@ -189,4 +190,10 @@ export class Util {
   public static countLines(input: string): number {
     return input.split(/\r\n|\r|\n/).length;
   }
+
+  public static isPathRelativeTo(parentPath: string, childPath: string): boolean {
+    const rpp = path.resolve(parentPath);
+    const rcp = path.resolve(childPath);
+    return rcp.startsWith(rpp.endsWith(path.sep) ? rpp : `${rpp}${path.sep}`);
+  }
 }