[v20.x] backport libuv wtf-8 decoding fix

deps/uv/src/win/fs.c

@@ -176,9 +176,11 @@ static int32_t fs__decode_wtf8_char(const char** input) {
   if ((b4 & 0xC0) != 0x80)
     return -1; /* invalid: not a continuation byte */
   code_point = (code_point << 6) | (b4 & 0x3F);
-  if (b1 <= 0xF4)
+  if (b1 <= 0xF4) {
+    code_point &= 0x1FFFFF;
     if (code_point <= 0x10FFFF)
       return code_point; /* four-byte character */
+  }
 
   /* code point too large */
   return -1;

test/parallel/test-fs-operations-with-surrogate-pairs.js

@@ -0,0 +1,31 @@
+'use strict';
+
+require('../common');
+const fs = require('node:fs');
+const path = require('node:path');
+const assert = require('node:assert');
+const { describe, it } = require('node:test');
+const tmpdir = require('../common/tmpdir');
+
+tmpdir.refresh();
+
+describe('File operations with filenames containing surrogate pairs', () => {
+  it('should write, read, and delete a file with surrogate pairs in the filename', () => {
+    // Create a temporary directory
+    const tempdir = fs.mkdtempSync(tmpdir.resolve('emoji-fruit-🍇 🍈 🍉 🍊 🍋'));
+    assert.strictEqual(fs.existsSync(tempdir), true);
+
+    const filename = '🚀🔥🛸.txt';
+    const content = 'Test content';
+
+    // Write content to a file
+    fs.writeFileSync(path.join(tempdir, filename), content);
+
+    // Read content from the file
+    const readContent = fs.readFileSync(path.join(tempdir, filename), 'utf8');
+
+    // Check if the content matches
+    assert.strictEqual(readContent, content);
+
+  });
+});