crypto: do not overwrite _writableState.defaultEncoding

This only affects the writable side of LazyTransform and should not change the behavior of any LazyTransform streams (Cipher, Decipher, Cipheriv, Decipheriv, Hash, Hmac). If the user does not set defaultEncoding when creating a transform stream, WritableState uses 'utf8' by default. Only LazyTransform overwrites this with 'buffer' for strict backward compatibility. This was necessary when crypto.DEFAULT_ENCODING still existed. Now that DEFAULT_ENCODING has been removed, defaultEncoding is always 'buffer'. The writable side of LazyTransform appears to treat 'utf8' and 'buffer' in exactly the same way. Therefore, there seems to be no need to overwrite _writableState.defaultEncoding at this point. Nevertheless, because Node.js has failed to hide implementation details such as _writableState from the ecosystem, we may want to consider this a breaking change. Refs: #47182 Refs: #8611 PR-URL: #49140 Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Rafael Gonzaga <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

Author: tniessen

lib/internal/streams/lazy_transform.js

@@ -23,11 +23,6 @@ function makeGetter(name){
 returnfunction(){
 stream.Transform.call(this,this._options);
 this._writableState.decodeStrings=false;
-
-if(!this._options||!this._options.defaultEncoding){
-this._writableState.defaultEncoding='buffer';// TODO(tniessen): remove
-}
-
 returnthis[name];
 };
 }

test/parallel/test-crypto.js

@@ -298,6 +298,9 @@ function testEncoding(options, assertionHash){
 lethashValue='';
 
 hash.on('data',(data)=>{
+// The defaultEncoding has no effect on the hash value. It only affects data
+// consumed by the Hash transform stream.
+assert(Buffer.isBuffer(data));
 hashValue+=data.toString('hex');
 });
 
@@ -307,6 +310,8 @@ function testEncoding(options, assertionHash){
 
 hash.write('öäü');
 hash.end();
+
+assert.strictEqual(hash._writableState.defaultEncoding,options?.defaultEncoding??'utf8');
 }
 
 // Hash of "öäü" in utf8 format