path: fix normalization of Windows device paths missing colon

test: add test case for device paths missing colon

style: fix linter errors

path: fix normalization of Windows device paths missing colon

Author: HassanFleyah

lib/path.js

@@ -401,12 +401,27 @@ const win32 = {
                 // We matched a device root (e.g. \\\\.\\PHYSICALDRIVE0)
                 device = `\\\\${firstPart}`;
                 rootEnd = 4;
-                const colonIndex = StringPrototypeIndexOf(path, ':');
-                // Special case: handle \\?\COM1: or similar reserved device paths
-                const possibleDevice = StringPrototypeSlice(path, 4, colonIndex + 1);
-                if (isWindowsReservedName(possibleDevice, possibleDevice.length - 1)) {
-                  device = `\\\\?\\${possibleDevice}`;
-                  rootEnd = 4 + possibleDevice.length;
+                // Determine the end of the root part (the first slash or end of string)
+                let rootPartEnd = 4;
+                while (rootPartEnd < len && !isPathSeparator(StringPrototypeCharCodeAt(path, rootPartEnd))) {
+                  rootPartEnd++;
+                }
+
+                const rootPart = StringPrototypeSlice(path, 4, rootPartEnd);
+                const colonIndexInRoot = StringPrototypeIndexOf(rootPart, ':');
+
+                if (colonIndexInRoot !== -1) {
+                  // Handle \\?\COM1: or similar reserved device paths with colon
+                  if (isWindowsReservedName(rootPart, colonIndexInRoot)) {
+                    device = `\\\\${firstPart}\\${rootPart}`;
+                    rootEnd = 4 + rootPart.length;
+                  }
+                } else {
+                  // Handle \\.\CON or \\?\CON where the colon is missing
+                  if (isWindowsReservedName(rootPart, rootPart.length)) {
+                    device = `\\\\${firstPart}\\${rootPart}`;
+                    rootEnd = 4 + rootPart.length;
+                  }
                 }
               } else if (j === len) {
                 // We matched a UNC root only
@@ -471,7 +486,8 @@ const win32 = {
       } while ((index = StringPrototypeIndexOf(path, ':', index + 1)) !== -1);
     }
     const colonIndex = StringPrototypeIndexOf(path, ':');
-    if (isWindowsReservedName(path, colonIndex)) {
+    // Ensure colonIndex is valid before calling isWindowsReservedName
+    if (colonIndex !== -1 && isWindowsReservedName(path, colonIndex)) {
       return `.\\${device ?? ''}${tail}`;
     }
     if (device === undefined) {

test/parallel/test-path-win32-normalize-device-missing-colon.js

@@ -0,0 +1,27 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const path = require('path');
+
+// هذا السطر يمنع تشغيل الاختبار على غير ويندوز لأنه خاص بويندوز فقط
+if (!common.isWindows)
+  common.skip('this test is for win32 only');
+
+// Test cases for reserved device names missing the trailing colon
+// See: https://github.com/nodejs/node/pull/[YOUR_PR_NUMBER] (optional)
+
+// 1. Check \\.\CON (Missing colon)
+assert.strictEqual(path.win32.normalize('\\\\.\\CON'), '\\\\.\\CON');
+assert.strictEqual(path.win32.normalize('\\\\.\\con'), '\\\\.\\con'); // Case insensitive
+
+// 2. Check \\?\CON (Missing colon)
+assert.strictEqual(path.win32.normalize('\\\\?\\CON'), '\\\\?\\CON');
+assert.strictEqual(path.win32.normalize('\\\\?\\con'), '\\\\?\\con');
+
+// 3. Check that regular files are NOT affected (Sanity check)
+assert.strictEqual(path.win32.normalize('\\\\.\\PhysicalDrive0'), '\\\\.\\PhysicalDrive0');
+
+// 4. Check join behavior (to ensure it acts as a root)
+// If it's a root, joining '..' should not strip the device.
+const joined = path.win32.join('\\\\.\\CON', '..');
+assert.strictEqual(joined, '\\\\.\\CON');

test/parallel/test-path-win32-normalize-device-names.js

@@ -115,6 +115,27 @@ for (const { input, expected } of normalizeDeviceNameTests) {
                      `path.win32.normalize(${JSON.stringify(input)}) === ${JSON.stringify(expected)}, but got ${JSON.stringify(actual)}`);
 }
 
+const normalizeReservedDeviceRootTests = [
+  { input: '\\\\.\\CON', expected: '\\\\.\\CON' },
+  { input: '\\\\?\\PRN', expected: '\\\\?\\PRN' },
+  { input: '\\\\.\\AUX\\file.txt', expected: '\\\\.\\AUX\\file.txt' },
+  { input: '\\\\?\\COM1/folder/file', expected: '\\\\?\\COM1\\folder\\file' },
+  { input: '\\\\.\\CON\\file:ADS', expected: '\\\\.\\CON\\file:ADS' },
+  { input: '\\\\?\\PRN\\data:stream', expected: '\\\\?\\PRN\\data:stream' },
+  { input: '\\\\.\\CON-prefix', expected: '\\\\.\\CON-prefix' },
+  { input: '\\\\?\\PRN-suffix', expected: '\\\\?\\PRN-suffix' },
+  { input: '\\\\.\\NOT_A_DEVICE', expected: '\\\\.\\NOT_A_DEVICE' },
+];
+
+for (const { input, expected } of normalizeReservedDeviceRootTests) {
+  const actual = path.win32.normalize(input);
+  assert.strictEqual(
+    actual,
+    expected,
+    `path.win32.normalize(${JSON.stringify(input)}) === ${JSON.stringify(expected)}, but got ${JSON.stringify(actual)}`
+  );
+}
+
 assert.strictEqual(path.win32.normalize('CON:foo/../bar'), '.\\CON:bar');
 
 // This should NOT be prefixed because 'c:' is treated as a drive letter.