[Fix] Infinite while loop when called on root folder, add tests

package.json

@@ -22,7 +22,7 @@
     "lint:fix": "eslint --fix .",
     "typecheck": "tsc --noEmit",
     "test": "npm-run-all test:coverage lint typecheck",
-    "test:unit": "NODE_ENV=test TS_NODE_PROJECT='tsconfig.test.json' ava",
+    "test:unit": "cross-env NODE_ENV=test TS_NODE_PROJECT='tsconfig.test.json' ava",
     "test:coverage": "nyc --reporter=lcov --reporter=text npm run test:unit --silent"
   },
   "ava": {
@@ -50,6 +50,7 @@
     "@typescript-eslint/eslint-plugin": "5.59.6",
     "@typescript-eslint/parser": "5.59.6",
     "ava": "5.2.0",
+    "cross-env": "^7.0.3",
     "eslint": "8.41.0",
     "eslint-plugin-ava": "14.0.0",
     "eslint-plugin-import": "2.27.5",

src/functions/getFirstExistingParentPath.ts

@@ -8,15 +8,31 @@ import Dependencies from '@/src/types/dependencies'
  * @param dependencies - Dependencies container
  */
 async function getFirstExistingParentPath(directoryPath: string, dependencies: Dependencies): Promise<string> {
-	let parentDirectoryPath = directoryPath
+	let parentDirectoryPath = dependencies.pathNormalize(directoryPath)
 	let parentDirectoryFound = await isDirectoryExisting(parentDirectoryPath, dependencies)
 
-	while (!parentDirectoryFound) {
-		parentDirectoryPath = dependencies.pathNormalize(parentDirectoryPath + '/..')
+	const FAILED_TO_FIND_EXISTING_DIRECTORY_VALUE = ''
+
+	/**
+	 * Linux max file path length is 4096 characters.
+	 * With / separators and 1 letter folder names, this gives us a max of ~2048 folders to traverse.
+	 * This is much less error prone than a while loop.
+	 */
+	const maxNumberOfFolders = 2048
+	for (let i = 0; i < maxNumberOfFolders && !parentDirectoryFound; ++i) {
+		const newParentDirectoryPath = dependencies.pathNormalize(parentDirectoryPath + '/..')
+		if (parentDirectoryPath === newParentDirectoryPath) {
+			return FAILED_TO_FIND_EXISTING_DIRECTORY_VALUE
+		}
+		parentDirectoryPath = newParentDirectoryPath
 		parentDirectoryFound = await isDirectoryExisting(parentDirectoryPath, dependencies)
 	}
 
-	return parentDirectoryPath
+	if (parentDirectoryPath !== '.') {
+		return parentDirectoryPath
+	}
+
+	return FAILED_TO_FIND_EXISTING_DIRECTORY_VALUE
 }
 
 export default getFirstExistingParentPath

test/__helpers__/mockDependencies.ts

@@ -1,4 +1,4 @@
-import { normalize } from 'node:path'
+import { normalize, sep } from 'node:path'
 import { promisify } from 'node:util'
 
 import Dependencies from '@/src/types/dependencies'
@@ -12,7 +12,7 @@ function mockDependencies(overrides?: Partial<Dependencies>, options?: {
 		release: '11.5.0',
 		fsAccess: () => Promise.resolve(),
 		pathNormalize: normalize,
-		pathSep: '/',
+		pathSep: sep,
 		cpExecFile: async () => {
 			await promisify(process.nextTick)
 

test/functions/getFirstExistingParentPath.spec.ts

@@ -1,24 +1,44 @@
+import { normalize } from 'node:path'
+
 import test from 'ava'
 import { PathLike } from 'fs'
 
 import getFirstExistingParentPath from '@/src/functions/getFirstExistingParentPath'
 import mockDependencies from '@/test/__helpers__/mockDependencies'
 
+const getDependencies = (parentPath: string) => mockDependencies({
+	fsAccess: async (directoryPath: PathLike) => directoryPath === parentPath ? Promise.resolve() : Promise.reject(new Error('File does not exists')),
+})
 
 test('unix: get first existing parent path', async t => {
-	const parentPath = '/home/Alex'
-	const dependencies = mockDependencies({
-		fsAccess: async (directoryPath: PathLike) => directoryPath === parentPath ? Promise.resolve() : Promise.reject(new Error('File does not exists')),
-	})
+	const parentPath = normalize('/home/Alex')
+	const dependencies = getDependencies(parentPath)
 
 	t.is(await getFirstExistingParentPath('/home/Alex/games/Some/Game', dependencies), parentPath)
 })
 
 test('unix: get first parent can be the path itself', async t => {
-	const parentPath = '/home/Alex'
-	const dependencies = mockDependencies({
-		fsAccess: async (directoryPath: PathLike) => directoryPath === parentPath ? Promise.resolve() : Promise.reject(new Error('File does not exists')),
-	})
+	const parentPath = normalize('/home/Alex')
+	const dependencies = getDependencies(parentPath)
 
 	t.is(await getFirstExistingParentPath(parentPath, dependencies), parentPath)
 })
+
+test('win32: Gets parent to C:\\HyperPlay', async t => {
+	const parentPath = normalize('C:\\')
+	const dependencies = getDependencies(parentPath)
+	t.is(await getFirstExistingParentPath(normalize('C:\\HyperPlay'), dependencies), parentPath)
+})
+
+test('win32: Returns root folder when called on root folder', async t => {
+	const parentPath = normalize('C:\\')
+	const dependencies = getDependencies(parentPath)
+	t.is(await getFirstExistingParentPath(parentPath, dependencies), parentPath)
+})
+
+test('win32: returns empty string when drive does not exist', async t => {
+	const drivePathThatExists = normalize('C:\\')
+	const dependencies = getDependencies(drivePathThatExists)
+	const drivePathThatDoesNotExist = normalize('Z:\\')
+	t.is(await getFirstExistingParentPath(drivePathThatDoesNotExist, dependencies), '')
+})