fixup! fs: deprecate never throw behaviour in fs.existsSync

lib/fs.js

@@ -273,11 +273,7 @@ ObjectDefineProperty(exists, kCustomPromisifiedSymbol, {
   },
 });
 
-// fs.existsSync never throws, it only returns true or false.
-// Since fs.existsSync never throws, users have established
-// the expectation that passing invalid arguments to it, even like
-// fs.existsSync(), would only get a false in return, so we cannot signal
-// validation errors to users properly out of compatibility concerns.
+let showExistsDeprecation = true;
 /**
  * Synchronously tests whether or not the given path exists.
  * @param {string | Buffer | URL} path
@@ -287,9 +283,11 @@ function existsSync(path) {
   try {
     path = getValidatedPath(path);
   } catch {
-    if (!deprecationWarningEmitted) {
-      process.emitWarning('Passing invalid argument types to fs.existsSync is deprecated', 'DeprecationWarning', 'DEP0187');
-      deprecationWarningEmitted = true;
+    if (showExistsDeprecation) {
+      process.emitWarning(
+        'Passing invalid argument types to fs.existsSync is deprecated', 'DeprecationWarning', 'DEP0187',
+      );
+      showExistsDeprecation = false;
     }
     return false;
   }

test/parallel/test-fs-exists.js

@@ -51,6 +51,8 @@ assert(fs.existsSync(f));
 assert(!fs.existsSync(`${f}-NO`));
 
 // fs.existsSync() never throws
+const msg = 'Passing invalid argument types to fs.existsSync is deprecated';
+common.expectWarning('DeprecationWarning', msg, 'DEP0187');
 assert(!fs.existsSync());
 assert(!fs.existsSync({}));
 assert(!fs.existsSync(new URL('https://foo')));