zlib: allow writes after readable 'end' to finish

Call the callback for writes that occur after the stream is closed.
This also requires changes to the code to not call `.destroy()`
on the stream in `.on('end')`, and to ignore chunks written
afterwards.
Previously, these writes would just queue up silently, as their
`_write()` callback would never have been called.
Fixes: #30976
PR-URL: #31082
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: addaleax

lib/zlib.js

@@ -275,7 +275,7 @@ function ZlibBase(opts, mode, handle, { flush, finishFlush, fullFlush }) {
 this._defaultFlushFlag=flush;
 this._finishFlushFlag=finishFlush;
 this._defaultFullFlushFlag=fullFlush;
-this.once('end',this.close);
+this.once('end',_close.bind(null,this));
 this._info=opts&&opts.info;
 }
 ObjectSetPrototypeOf(ZlibBase.prototype,Transform.prototype);
@@ -487,7 +487,7 @@ function processChunkSync(self, chunk, flushFlag) {
 
 functionprocessChunk(self,chunk,flushFlag,cb){
 consthandle=self._handle;
-assert(handle,'zlib binding closed');
+if(!handle)returnprocess.nextTick(cb);
 
 handle.buffer=chunk;
 handle.cb=cb;
@@ -513,13 +513,9 @@ function processCallback() {
 constself=this[owner_symbol];
 conststate=self._writeState;
 
-if(self._hadError){
-this.buffer=null;
-return;
-}
-
-if(self.destroyed){
+if(self._hadError||self.destroyed){
 this.buffer=null;
+this.cb();
 return;
 }
 
@@ -539,6 +535,7 @@ function processCallback() {
 }
 
 if(self.destroyed){
+this.cb();
 return;
 }
 

test/parallel/test-zlib-write-after-end.js

@@ -0,0 +1,16 @@
+'use strict';
+constcommon=require('../common');
+constzlib=require('zlib');
+
+// Regression test for https://github.com/nodejs/node/issues/30976
+// Writes to a stream should finish even after the readable side has been ended.
+
+constdata=zlib.deflateRawSync('Welcome');
+
+constinflate=zlib.createInflateRaw();
+
+inflate.resume();
+inflate.write(data,common.mustCall());
+inflate.write(Buffer.from([0x00]),common.mustCall());
+inflate.write(Buffer.from([0x00]),common.mustCall());
+inflate.flush(common.mustCall());