fix: directory symlink handling (#200)

Co-authored-by: JounQin <admin@1stg.me>

Author: ConradHughes

.changeset/wet-sloths-destroy.md

@@ -0,0 +1,5 @@
+---
+"pretty-quick": patch
+---
+
+fix: directory symlink handling - close #196

package.json

@@ -84,6 +84,7 @@
     "npm-run-all": "^4.1.5",
     "prettier": "^3.5.3",
     "pretty-quick": "link:.",
+    "simple-git-hooks": "^2.9.0",
     "size-limit": "^11.2.0",
     "size-limit-preset-node-lib": "^0.3.0",
     "ts-jest": "^29.2.6",

src/isSupportedExtension.ts

@@ -1,12 +1,24 @@
 /* eslint-disable unicorn/filename-case */
 
+import fs from 'fs/promises'
+
 import {
   type FileInfoOptions,
   getFileInfo,
   resolveConfig as prettierResolveConfig,
 } from 'prettier'
 
 export default (resolveConfig?: boolean) => async (file: string) => {
+  const stat = await fs.stat(file).catch(_error => null)
+  /* If file exists but is actually a directory, getFileInfo might end up trying
+   * to open it and read it as a file, so let's not let that happen.  On the
+   * other hand, the tests depend on our not failing out with files that don't
+   * exist, so permit nonexistent files to go through (they appear to be
+   * detected by suffix, so never get read).
+   */
+  if (stat?.isDirectory()) {
+    return false
+  }
   const config = (await prettierResolveConfig(file, {
     editorconfig: true,
   })) as FileInfoOptions

test/isSupportedExtension.spec.ts

@@ -1,10 +1,25 @@
 /* eslint-disable unicorn/filename-case */
 
+import mock from 'mock-fs'
 import { getFileInfo } from 'prettier'
 
 import isSupportedExtension from 'pretty-quick/isSupportedExtension'
 
-afterEach(() => jest.clearAllMocks())
+beforeEach(() => {
+  mock({
+    'banana.js': 'banana()',
+    'banana.txt': 'yellow',
+    'bsym.js': mock.symlink({ path: 'banana.js' }),
+    'bsym.txt': mock.symlink({ path: 'banana.js' }), // Yes extensions don't match
+    dsym: mock.symlink({ path: 'subdir' }),
+    subdir: {},
+  })
+})
+
+afterEach(() => {
+  mock.restore()
+  jest.clearAllMocks()
+})
 
 test('return true when file with supported extension passed in', async () => {
   expect(await isSupportedExtension(true)('banana.js')).toEqual(true)
@@ -30,3 +45,24 @@ test('do not resolve config when false passed', async () => {
     resolveConfig: false,
   })
 })
+
+test('return true when file symlink with supported extension passed in', async () => {
+  expect(await isSupportedExtension(true)('bsym.js')).toEqual(true)
+  expect(getFileInfo).toHaveBeenCalledWith('bsym.js', {
+    file: 'bsym.js',
+    resolveConfig: true,
+  })
+})
+
+test('return false when file symlink with unsupported extension passed in', async () => {
+  expect(await isSupportedExtension(true)('bsym.txt')).toEqual(false)
+  expect(getFileInfo).toHaveBeenCalledWith('bsym.txt', {
+    file: 'bsym.txt',
+    resolveConfig: true,
+  })
+})
+
+test('return false when directory symlink passed in', async () => {
+  expect(await isSupportedExtension(true)('dsym')).toEqual(false)
+  expect(getFileInfo).not.toHaveBeenCalled()
+})

yarn.lock

@@ -12946,6 +12946,7 @@ __metadata:
     picomatch: ^4.0.2
     prettier: ^3.5.3
     pretty-quick: "link:."
+    simple-git-hooks: ^2.9.0
     size-limit: ^11.2.0
     size-limit-preset-node-lib: ^0.3.0
     tinyexec: ^0.3.2