fix(windows): resolve CI failures with file locking and import resolution

Fixes multiple Windows-specific CI failures related to file system operations
and ESLint configuration.

Changes:
- Add retry logic with exponential backoff for file writes (EPERM/EBUSY errors)
- Add retry logic for temp directory cleanup in test afterEach hooks
- Add .mjs files to ESLint test file patterns for import resolution
- Handle transient Windows file handle locks during test cleanup

Technical details:
- EditableJson.save() retries up to 3 times with 10/20/40ms backoff
- Test cleanup retries up to 5 times with 50ms + 100ms delays
- ESLint now ignores import resolution for test/**/*.mjs files
- Fixes: json.test.ts EPERM errors and esm-imports.test.mjs lint failures

Author: jdalton

.config/eslint.config.mjs

@@ -346,7 +346,7 @@ const eslintConfig = [
   },
   {
     // Relax rules for test files - testing code has different conventions
-    files: ['test/**/*.ts', 'test/**/*.mts'],
+    files: ['test/**/*.ts', 'test/**/*.mts', 'test/**/*.mjs'],
     rules: {
       'n/no-missing-import': 'off',
       'import-x/no-unresolved': 'off',

src/json/edit.ts

@@ -41,6 +41,44 @@ function getFs() {
   return _fs as typeof import('node:fs')
 }
 
+/**
+ * Retry a file write operation with exponential backoff on Windows EPERM errors.
+ * Windows can have transient file locking issues with temp directories.
+ * @private
+ */
+async function retryWrite(
+  filepath: string,
+  content: string,
+  retries = 3,
+  baseDelay = 10,
+): Promise<void> {
+  const { promises: fsPromises } = getFs()
+
+  for (let attempt = 0; attempt <= retries; attempt++) {
+    try {
+      // eslint-disable-next-line no-await-in-loop
+      await fsPromises.writeFile(filepath, content)
+      return
+    } catch (err) {
+      const isLastAttempt = attempt === retries
+      const isEperm =
+        err instanceof Error &&
+        'code' in err &&
+        (err.code === 'EPERM' || err.code === 'EBUSY')
+
+      // Only retry on Windows EPERM/EBUSY errors, and not on the last attempt
+      if (!isEperm || isLastAttempt) {
+        throw err
+      }
+
+      // Exponential backoff: 10ms, 20ms, 40ms
+      const delay = baseDelay * 2 ** attempt
+      // eslint-disable-next-line no-await-in-loop
+      await new Promise(resolve => setTimeout(resolve, delay))
+    }
+  }
+}
+
 /**
  * Parse JSON content and extract formatting metadata.
  * @private
@@ -216,9 +254,8 @@ export function getEditableJsonClass<
         // Generate file content
         const fileContent = stringifyWithFormatting(sortedContent, formatting)
 
-        // Save to disk
-        const { promises: fsPromises } = getFs()
-        await fsPromises.writeFile(this.filename, fileContent)
+        // Save to disk with retry logic for Windows file locking issues
+        await retryWrite(this.filename, fileContent)
         this._readFileContent = fileContent
         this._readFileJson = parseJson(fileContent)
         return true

test/unit/json.test.ts

@@ -16,6 +16,7 @@
 import { mkdtemp, readFile, writeFile } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
+import { setTimeout as sleep } from 'node:timers/promises'
 
 import { safeDelete } from '@socketsecurity/lib/fs'
 import { getEditableJsonClass } from '@socketsecurity/lib/json/edit'
@@ -766,7 +767,25 @@ describe('json', () => {
 
     afterEach(async () => {
       if (testDir) {
-        await safeDelete(testDir)
+        // On Windows, add retry logic for directory deletion due to file handle timing
+        if (process.platform === 'win32') {
+          let retries = 5
+          while (retries > 0) {
+            try {
+              await sleep(50)
+              await safeDelete(testDir)
+              break
+            } catch (err) {
+              retries--
+              if (retries === 0) {
+                throw err
+              }
+              await sleep(100)
+            }
+          }
+        } else {
+          await safeDelete(testDir)
+        }
       }
     })