stream: fix fd is null when calling clearBuffer

PR-URL: #50994Fixes: #50979
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Raz Luvaton <rluvaton@gmail.com>
Reviewed-By: Robert Nagy <ronagy@icloud.com>

Author: kylo5aby

lib/internal/streams/writable.js

@@ -733,7 +733,8 @@ function errorBuffer(state) {
 
 // If there's something in the buffer waiting, then process it.
 functionclearBuffer(stream,state){
-if((state[kState]&(kDestroyed|kBufferProcessing|kCorked|kBuffered))!==kBuffered){
+if((state[kState]&(kDestroyed|kBufferProcessing|kCorked|kBuffered|kConstructed))!==
+(kBuffered|kConstructed)){
 return;
 }
 

test/parallel/test-file-write-stream5.js

@@ -0,0 +1,28 @@
+'use strict';
+
+// Test 'uncork' for WritableStream.
+// Refs: https://github.com/nodejs/node/issues/50979
+
+constcommon=require('../common');
+constfs=require('fs');
+constassert=require('assert');
+consttest=require('node:test');
+consttmpdir=require('../common/tmpdir');
+
+constfilepath=tmpdir.resolve('write_stream.txt');
+tmpdir.refresh();
+
+constdata='data';
+
+test('writable stream uncork',()=>{
+constfileWriteStream=fs.createWriteStream(filepath);
+
+fileWriteStream.on('finish',common.mustCall(()=>{
+constwrittenData=fs.readFileSync(filepath,'utf8');
+assert.strictEqual(writtenData,data);
+}));
+fileWriteStream.cork();
+fileWriteStream.write(data,common.mustCall());
+fileWriteStream.uncork();
+fileWriteStream.end();
+});