zlib: fix assert fail for bad write in object mode

add4b0a introduced a regression from Node 8 to Node 9 by removing the
`ArrayBuffer.isView(chunk)` check in `Zlib.prototype._transform` without
properly forcing `opts.objectMode` to `false` in the constructor because
the change to `opts` occurs after `opts` has been passed to the
`Transform` constructor.  This commit fixes the issue by moving the call
to `Transform` after the changes to `opts`.

The regression can be demonstrated by running

    node -e 'require("zlib").Gunzip({objectMode: true}).write({})'

On Node 8 this correctly throws a `TypeError`:

    events.js:183
          throw er; // Unhandled 'error' event
          ^

    TypeError: invalid input
        at Gunzip._transform (zlib.js:367:15)
        at Gunzip.Transform._read (_stream_transform.js:186:10)
        at Gunzip.Transform._write (_stream_transform.js:174:12)
        at doWrite (_stream_writable.js:387:12)
        at writeOrBuffer (_stream_writable.js:373:5)
        at Gunzip.Writable.write (_stream_writable.js:290:11)
        at [eval]:1:44
        at ContextifyScript.Script.runInThisContext (vm.js:50:33)
        at Object.runInThisContext (vm.js:139:38)
        at Object.<anonymous> ([eval]-wrapper:6:22)

On Node 9 this causes an assertion failure:

    node[21732]: ../src/node_zlib.cc:179:static void node::{anonymous}::ZCtx::Write(const v8::FunctionCallbackInfo<v8::Value>&) [with bool async = true]: Assertion `Buffer::HasInstance(args[1])' failed.
     1: node::Abort() [node]
     2: node::Assert(char const* const (*) [4]) [node]
     3: 0x1250916 [node]
     4: v8::internal::FunctionCallbackArguments::Call(void (*)(v8::FunctionCallbackInfo<v8::Value> const&)) [node]
     5: 0xb7547c [node]
     6: v8::internal::Builtin_HandleApiCall(int, v8::internal::Object**, v8::internal::Isolate*) [node]
     7: 0x20c44b8842fd
    Aborted

Signed-off-by: Kevin Locke <[email protected]>
PR-URL: #16960
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

lib/zlib.js

@@ -154,7 +154,6 @@ function flushCallback(level, strategy, callback) {
 // true or false if there is anything in the queue when
 // you call the .write() method.
 function Zlib(opts, mode) {
-  Transform.call(this, opts);
   var chunkSize = Z_DEFAULT_CHUNK;
   var flush = Z_NO_FLUSH;
   var finishFlush = Z_FINISH;
@@ -259,6 +258,7 @@ function Zlib(opts, mode) {
       opts.writableObjectMode = false;
     }
   }
+  Transform.call(this, opts);
   this.bytesRead = 0;
   this._handle = new binding.Zlib(mode);
   this._handle.jsref = this; // Used by processCallback() and zlibOnError()

test/parallel/test-zlib-object-write.js

@@ -0,0 +1,11 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+const { Gunzip } = require('zlib');
+
+const gunzip = new Gunzip({ objectMode: true });
+assert.throws(
+  () => gunzip.write({}),
+  TypeError
+);