fs: fix existsSync for invalid symlink at win32

Fixes: #30538
PR-URL: #30556
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: pd4d10

lib/fs.js

@@ -228,7 +228,16 @@ function existsSync(path) {
 returnfalse;
 }
 constctx={ path };
-binding.access(pathModule.toNamespacedPath(path),F_OK,undefined,ctx);
+constnPath=pathModule.toNamespacedPath(path);
+binding.access(nPath,F_OK,undefined,ctx);
+
+// In case of an invalid symlink, `binding.access()` on win32
+// will **not** return an error and is therefore not enough.
+// Double check with `binding.stat()`.
+if(isWindows&&ctx.errno===undefined){
+binding.stat(nPath,false,undefined,ctx);
+}
+
 returnctx.errno===undefined;
 }
 

test/parallel/test-fs-symlink-dir-junction.js

@@ -53,3 +53,20 @@ fs.symlink(linkData, linkPath, 'junction', common.mustCall(function(err) {
 }));
 }));
 }));
+
+// Test invalid symlink
+{
+constlinkData=fixtures.path('/not/exists/dir');
+constlinkPath=path.join(tmpdir.path,'invalid_junction_link');
+
+fs.symlink(linkData,linkPath,'junction',common.mustCall(function(err){
+assert.ifError(err);
+
+assert(!fs.existsSync(linkPath));
+
+fs.unlink(linkPath,common.mustCall(function(err){
+assert.ifError(err);
+assert(!fs.existsSync(linkPath));
+}));
+}));
+}

test/parallel/test-fs-symlink-dir.js

@@ -44,3 +44,25 @@ for (const linkTarget of linkTargets) {
 testAsync(linkTarget,`${linkPath}-${path.basename(linkTarget)}-async`);
 }
 }
+
+// Test invalid symlink
+{
+functiontestSync(target,path){
+fs.symlinkSync(target,path);
+assert(!fs.existsSync(path));
+}
+
+functiontestAsync(target,path){
+fs.symlink(target,path,common.mustCall((err)=>{
+assert.ifError(err);
+assert(!fs.existsSync(path));
+}));
+}
+
+for(constlinkTargetoflinkTargets.map((p)=>p+'-broken')){
+for(constlinkPathoflinkPaths){
+testSync(linkTarget,`${linkPath}-${path.basename(linkTarget)}-sync`);
+testAsync(linkTarget,`${linkPath}-${path.basename(linkTarget)}-async`);
+}
+}
+}

test/parallel/test-fs-symlink.js

@@ -58,6 +58,18 @@ fs.symlink(linkData, linkPath, common.mustCall(function(err) {
 }));
 }));
 
+// Test invalid symlink
+{
+constlinkData=fixtures.path('/not/exists/file');
+constlinkPath=path.join(tmpdir.path,'symlink2.js');
+
+fs.symlink(linkData,linkPath,common.mustCall(function(err){
+assert.ifError(err);
+
+assert(!fs.existsSync(linkPath));
+}));
+}
+
 [false,1,{},[],null,undefined].forEach((input)=>{
 consterrObj={
 code: 'ERR_INVALID_ARG_TYPE',