From b3f63ec43c04158e0ba00f541aa8ffb609d037d9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Iiro=20J=C3=A4ppinen?= <iiro@jappinen.fi>
Date: Fri, 22 Apr 2022 09:16:05 +0300
Subject: [PATCH] fix: correctly handle symlinked config files

---
 lib/searchConfigs.js       | 41 +++++++++++++++++++-------------------
 test/integration.test.js   | 16 +++++++++++++++
 test/searchConfigs.spec.js |  7 ++++---
 3 files changed, 41 insertions(+), 23 deletions(-)

diff --git a/lib/searchConfigs.js b/lib/searchConfigs.js
index ada2e426d..ebadd0144 100644
--- a/lib/searchConfigs.js
+++ b/lib/searchConfigs.js
@@ -14,7 +14,8 @@ const debugLog = debug('lint-staged:searchConfigs')
 
 const EXEC_GIT = ['ls-files', '-z', '--full-name']
 
-const filterPossibleConfigFiles = (file) => searchPlaces.includes(basename(file))
+const filterPossibleConfigFiles = (files) =>
+  files.filter((file) => searchPlaces.includes(basename(file)))
 
 const numberOfLevels = (file) => file.split('/').length
 
@@ -58,20 +59,18 @@ export const searchConfigs = async (
     return { [configPath]: validateConfig(config, filepath, logger) }
   }
 
-  /** Get all possible config files known to git */
-  const cachedFiles = parseGitZOutput(await execGit(EXEC_GIT, { cwd: gitDir })).filter(
-    filterPossibleConfigFiles
-  )
-
-  /** Get all possible config files from uncommitted files */
-  const otherFiles = parseGitZOutput(
-    await execGit([...EXEC_GIT, '--others', '--exclude-standard'], { cwd: gitDir })
-  ).filter(filterPossibleConfigFiles)
+  const [cachedFiles, otherFiles] = await Promise.all([
+    /** Get all possible config files known to git */
+    execGit(EXEC_GIT, { cwd: gitDir }).then(parseGitZOutput).then(filterPossibleConfigFiles),
+    /** Get all possible config files from uncommitted files */
+    execGit([...EXEC_GIT, '--others', '--exclude-standard'], { cwd: gitDir })
+      .then(parseGitZOutput)
+      .then(filterPossibleConfigFiles),
+  ])
 
   /** Sort possible config files so that deepest is first */
   const possibleConfigFiles = [...cachedFiles, ...otherFiles]
-    .map((file) => join(gitDir, file))
-    .map((file) => normalize(file))
+    .map((file) => normalize(join(gitDir, file)))
     .filter(isInsideDirectory(cwd))
     .sort(sortDeepestParth)
 
@@ -85,15 +84,17 @@ export const searchConfigs = async (
 
   /** Load and validate all configs to the above object */
   await Promise.all(
-    possibleConfigFiles
-      .map((configPath) => loadConfig({ configPath }, logger))
-      .map((promise) =>
-        promise.then(({ config, filepath }) => {
-          if (config) {
-            configs[filepath] = validateConfig(config, filepath, logger)
+    Object.keys(configs).map((configPath) =>
+      loadConfig({ configPath }, logger).then(({ config, filepath }) => {
+        if (config) {
+          if (configPath !== filepath) {
+            debugLog('Config file "%s" resolved to "%s"', configPath, filepath)
           }
-        })
-      )
+
+          configs[configPath] = validateConfig(config, filepath, logger)
+        }
+      })
+    )
   )
 
   /** Get validated configs from the above object, without any `null` values (not found) */
diff --git a/test/integration.test.js b/test/integration.test.js
index 8d427a0fa..b90a35c8e 100644
--- a/test/integration.test.js
+++ b/test/integration.test.js
@@ -1232,6 +1232,22 @@ describe('lint-staged', () => {
     expect(await readFile('a/very/deep/file/path/file.js')).toEqual('')
   })
 
+  it('should work with symlinked config file', async () => {
+    await appendFile('test.js', testJsFileUgly)
+
+    await writeFile('.config/.lintstagedrc.json', JSON.stringify(fixJsConfig.config))
+    await fs.ensureSymlink(
+      path.join(cwd, '.config/.lintstagedrc.json'),
+      path.join(cwd, '.lintstagedrc.json')
+    )
+
+    await execGit(['add', '.'])
+
+    await gitCommit()
+
+    expect(await readFile('test.js')).toEqual(testJsFilePretty) // file was fixed
+  })
+
   it('should support parent globs', async () => {
     // Add some empty files
     await writeFile('file.js', '')
diff --git a/test/searchConfigs.spec.js b/test/searchConfigs.spec.js
index 74be8a143..e7adcc206 100644
--- a/test/searchConfigs.spec.js
+++ b/test/searchConfigs.spec.js
@@ -78,17 +78,18 @@ describe('searchConfigs', () => {
   })
 
   it('should return config found from git', async () => {
-    const configPath = '.lintstagedrc.json'
+    const configFile = '.lintstagedrc.json'
+    const configPath = normalize(path.join(process.cwd(), configFile))
     const config = { '*.js': 'eslint' }
 
-    execGit.mockResolvedValueOnce(`${configPath}\u0000`)
+    execGit.mockResolvedValueOnce(`${configFile}\u0000`)
     loadConfig.mockResolvedValueOnce({ config, filepath: configPath })
 
     await expect(searchConfigs({})).resolves.toEqual({ [configPath]: config })
   })
 
   it('should return auto-discovered config from cwd when not found from git', async () => {
-    const configPath = '.lintstagedrc.json'
+    const configPath = normalize(path.join(process.cwd(), '.lintstagedrc.json'))
     const config = { '*.js': 'eslint' }
 
     loadConfig.mockResolvedValueOnce({ config, filepath: configPath })