zlib: do not leak on destroy

lib/zlib.js

@@ -430,6 +430,11 @@ Zlib.prototype.close = function close(callback) {
   this.destroy();
 };
 
+Zlib.prototype._destroy = function _destroy(err, callback) {
+  _close(this);
+  callback(err);
+};
+
 Zlib.prototype._transform = function _transform(chunk, encoding, cb) {
   var flushFlag = this._defaultFlushFlag;
   // We use a 'fake' zero-length chunk to carry information about flushes from
@@ -592,6 +597,10 @@ function processCallback() {
     assert(false, 'have should not go down');
   }
 
+  if (self.destroyed) {
+    return;
+  }
+
   // exhausted the output buffer, or used all the input create a new one.
   if (availOutAfter === 0 || self._outOffset >= self._chunkSize) {
     handle.availOutBefore = self._chunkSize;

test/parallel/test-zlib-close-in-ondata.js

@@ -0,0 +1,10 @@
+'use strict';
+
+const common = require('../common');
+const zlib = require('zlib');
+
+const ts = zlib.createGzip();
+const buf = Buffer.alloc(1024 * 1024 * 20);
+
+ts.on('data', common.mustCall(() => ts.close()));
+ts.end(buf);

test/parallel/test-zlib-destroy.js

@@ -0,0 +1,13 @@
+'use strict';
+
+require('../common');
+
+const assert = require('assert');
+const zlib = require('zlib');
+
+// verify that the zlib transform does clean up
+// the handle when calling destroy.
+
+const ts = zlib.createGzip();
+ts.destroy();
+assert.strictEqual(ts._handle, null);