zlib: check if the stream is destroyed before push

If the stream is destroyed while the transform is still being
applied, push() should not be called, and the internal state
should be cleared.

Refs: koajs/compress#60
PR-URL: nodejs#14330
Backport-PR-URL: nodejs#14396
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>

 Conflicts:
	lib/zlib.js

Author: mcollina

Diff for: lib/zlib.js

@@ -431,6 +431,9 @@ Zlib.prototype._processChunk = function _processChunk(chunk, flushFlag, cb) {
     if (self._hadError)
       return;
 
+    if (self.destroyed)
+      return;
+
     var have = availOutBefore - availOutAfter;
     assert(have >= 0, 'have should not go down');
 

Diff for: test/parallel/test-zlib-destroy-pipe.js

@@ -0,0 +1,21 @@
+'use strict';
+
+const common = require('../common');
+const zlib = require('zlib');
+const { Writable } = require('stream');
+
+// verify that the zlib transform does not error in case
+// it is destroyed with data still in flight
+
+const ts = zlib.createGzip();
+
+const ws = new Writable({
+  write: common.mustCall((chunk, enc, cb) => {
+    setImmediate(cb);
+    ts.destroy();
+  })
+});
+
+const buf = Buffer.allocUnsafe(1024 * 1024 * 20);
+ts.end(buf);
+ts.pipe(ws);