path: match Windows reserved names by component boundary

Author: HassanFleyah

lib/path.js

@@ -83,6 +83,31 @@ function isWindowsReservedName(path, colonIndex) {
   return ArrayPrototypeIncludes(WINDOWS_RESERVED_NAMES, devicePart);
 }
 
+function hasWindowsReservedNamePrefix(path) {
+  let firstPartEnd = path.length;
+  for (let i = 0; i < path.length; i++) {
+    if (isPathSeparator(StringPrototypeCharCodeAt(path, i))) {
+      firstPartEnd = i;
+      break;
+    }
+  }
+
+  const firstPart = StringPrototypeSlice(path, 0, firstPartEnd);
+  const colonIndex = StringPrototypeIndexOf(firstPart, ':');
+  const dotIndex = StringPrototypeIndexOf(firstPart, '.');
+  let reservedNameBoundary = colonIndex;
+
+  if (reservedNameBoundary === -1 ||
+      (dotIndex !== -1 && dotIndex < reservedNameBoundary)) {
+    reservedNameBoundary = dotIndex;
+  }
+
+  if (reservedNameBoundary <= 0)
+    return false;
+
+  return isWindowsReservedName(firstPart, reservedNameBoundary);
+}
+
 function isWindowsDeviceRoot(code) {
   return (code >= CHAR_UPPERCASE_A && code <= CHAR_UPPERCASE_Z) ||
          (code >= CHAR_LOWERCASE_A && code <= CHAR_LOWERCASE_Z);
@@ -470,8 +495,7 @@ const win32 = {
         }
       } while ((index = StringPrototypeIndexOf(path, ':', index + 1)) !== -1);
     }
-    const colonIndex = StringPrototypeIndexOf(path, ':');
-    if (isWindowsReservedName(path, colonIndex)) {
+    if (hasWindowsReservedNamePrefix(path)) {
       return `.\\${device ?? ''}${tail}`;
     }
     if (device === undefined) {

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

@@ -28,7 +28,7 @@ const normalizeDeviceNameTests = [
   { input: 'con:', expected: '.\\con:.' },
   { input: 'CON:.', expected: '.\\CON:.' },
   { input: 'coN:', expected: '.\\coN:.' },
-  { input: 'LPT9.foo', expected: 'LPT9.foo' },
+  { input: 'LPT9.foo', expected: '.\\LPT9.foo' },
   { input: 'COM9:', expected: '.\\COM9:.' },
   { input: 'COM9.', expected: '.\\COM9.' },
   { input: 'C:COM9', expected: 'C:COM9' },
@@ -76,7 +76,9 @@ const normalizeDeviceNameTests = [
   { input: 'D:bar', expected: 'D:bar' },
 
   { input: 'CON', expected: 'CON' },
-  { input: 'CON.TXT', expected: 'CON.TXT' },
+  { input: 'CON.TXT', expected: '.\\CON.TXT' },
+  { input: 'NUL.txt', expected: '.\\NUL.txt' },
+  { input: 'CONx', expected: 'CONx' },
   { input: 'COM10:', expected: '.\\COM10:' },
   { input: 'LPT10:', expected: '.\\LPT10:' },
   { input: 'CONNINGTOWER:', expected: '.\\CONNINGTOWER:' },