stream: use more accurate end-of-stream writable and readable detection

The value of stream.readable and stream.writable should not
be used to detect whether a stream is Writable or Readable.

Refs: #29395
PR-URL: #29409
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: James M Snell <[email protected]>

Author: ronag

lib/internal/streams/end-of-stream.js

@@ -13,6 +13,18 @@ function isRequest(stream) {
   return stream.setHeader && typeof stream.abort === 'function';
 }
 
+function isReadable(stream) {
+  return typeof stream.readable === 'boolean' ||
+    typeof stream.readableEnded === 'boolean' ||
+    !!stream._readableState;
+}
+
+function isWritable(stream) {
+  return typeof stream.writable === 'boolean' ||
+    typeof stream.writableEnded === 'boolean' ||
+    !!stream._writableState;
+}
+
 function eos(stream, opts, callback) {
   if (arguments.length === 2) {
     callback = opts;
@@ -47,8 +59,10 @@ function eos(stream, opts, callback) {
     };
   }
 
-  let readable = opts.readable || (opts.readable !== false && stream.readable);
-  let writable = opts.writable || (opts.writable !== false && stream.writable);
+  let readable = opts.readable ||
+    (opts.readable !== false && isReadable(stream));
+  let writable = opts.writable ||
+    (opts.writable !== false && isWritable(stream));
 
   const onlegacyfinish = () => {
     if (!stream.writable) onfinish();

test/parallel/test-stream-finished.js

@@ -318,3 +318,51 @@ const { promisify } = require('util');
   }));
   r.destroy();
 }
+
+{
+  // Test is readable check through readable
+  const streamLike = new EE();
+  streamLike.readable = false;
+  finished(streamLike, common.mustCall());
+  streamLike.emit('end');
+}
+
+{
+  // Test is readable check through readableEnded
+  const streamLike = new EE();
+  streamLike.readableEnded = true;
+  finished(streamLike, common.mustCall());
+  streamLike.emit('end');
+}
+
+{
+  // Test is readable check through _readableState
+  const streamLike = new EE();
+  streamLike._readableState = {};
+  finished(streamLike, common.mustCall());
+  streamLike.emit('end');
+}
+
+{
+  // Test is writable check through writable
+  const streamLike = new EE();
+  streamLike.writable = false;
+  finished(streamLike, common.mustCall());
+  streamLike.emit('finish');
+}
+
+{
+  // Test is writable check through writableEnded
+  const streamLike = new EE();
+  streamLike.writableEnded = true;
+  finished(streamLike, common.mustCall());
+  streamLike.emit('finish');
+}
+
+{
+  // Test is writable check through _writableState
+  const streamLike = new EE();
+  streamLike._writableState = {};
+  finished(streamLike, common.mustCall());
+  streamLike.emit('finish');
+}