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>

lib/zlib.js

@@ -264,7 +264,7 @@ 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;
 }
 Object.setPrototypeOf(ZlibBase.prototype, Transform.prototype);
@@ -476,7 +476,7 @@ function processChunkSync(self, chunk, flushFlag) {
 
 function processChunk(self, chunk, flushFlag, cb) {
  const handle = self._handle;
- assert(handle, 'zlib binding closed');
+ if (!handle) return process.nextTick(cb);
 
  handle.buffer = chunk;
  handle.cb = cb;
@@ -502,13 +502,9 @@ function processCallback() {
  const self = this[owner_symbol];
  const state = self._writeState;
 
- if (self._hadError) {
- this.buffer = null;
- return;
- }
-
- if (self.destroyed) {
+ if (self._hadError || self.destroyed) {
  this.buffer = null;
+ this.cb();
  return;
  }
 
@@ -528,6 +524,7 @@ function processCallback() {
  }
 
  if (self.destroyed) {
+ this.cb();
  return;
  }
 

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

@@ -0,0 +1,16 @@
+'use strict';
+const common = require('../common');
+const zlib = 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.
+
+const data = zlib.deflateRawSync('Welcome');
+
+const inflate = 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());