fs: fix cpSync() abort when dest is a dangling symlink

src/node_file.cc

@@ -4643,8 +4643,10 @@ static void CpSyncCheckPaths(const FunctionCallbackInfo<Value>& args) {
   auto dest_path_str = ConvertPathToUTF8(dest_path);
 
   if (!error_code) {
-    // Check if src and dest are identical.
-    if (std::filesystem::equivalent(src_path, dest_path)) {
+    // Check if src and dest are identical. A dangling dest symlink makes
+    // equivalent() fail, which means they are not the same file.
+    std::error_code equivalent_error;
+    if (std::filesystem::equivalent(src_path, dest_path, equivalent_error)) {
       static constexpr const char* message =
           "src and dest cannot be the same %s";
       return THROW_ERR_FS_CP_EINVAL(env, message, dest_path_str);

test/parallel/test-fs-cp-sync-file-over-dangling-symlink.mjs

@@ -0,0 +1,30 @@
+// This tests that cpSync() replaces a dangling symlink in dest with a file
+// instead of aborting the process.
+import { mustNotMutateObjectDeep } from '../common/index.mjs';
+import { nextdir } from '../common/fs.js';
+import assert from 'node:assert';
+import {
+  cpSync,
+  existsSync,
+  lstatSync,
+  mkdirSync,
+  readFileSync,
+  symlinkSync,
+  writeFileSync,
+} from 'node:fs';
+import { join } from 'node:path';
+import tmpdir from '../common/tmpdir.js';
+
+tmpdir.refresh();
+
+const dir = nextdir();
+mkdirSync(dir);
+const src = join(dir, 'src');
+const dest = join(dir, 'dest');
+writeFileSync(src, 'data');
+symlinkSync('missing', dest);
+
+cpSync(src, dest, mustNotMutateObjectDeep({ force: true }));
+assert(lstatSync(dest).isFile());
+assert.strictEqual(readFileSync(dest, 'utf8'), 'data');
+assert(!existsSync(join(dir, 'missing')));