stream: pipeline should only destroy un-finished streams

ronag · BethGriggs · commit 180b935b5890 · 2020-04-28T16:28:27.000+01:00
This PR logically reverts #31940 which has caused lots of unnecessary breakage in the ecosystem. This PR also aligns better with the actual documented behavior: `stream.pipeline()` will call `stream.destroy(err)` on all streams except: * `Readable` streams which have emitted `'end'` or `'close'`. * `Writable` streams which have emitted `'finish'` or `'close'`. The behavior introduced in #31940 was much more aggressive in terms of destroying streams. This was good for avoiding potential resources leaks however breaks some common assumputions in legacy streams. Furthermore, it makes the code simpler and removes some hacks. Fixes: #32954 Fixes: #32955 PR-URL: #32968 Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Mathias Buus <mathiasbuus@gmail.com>
diff --git a/lib/internal/streams/pipeline.js b/lib/internal/streams/pipeline.js
@@ -25,43 +25,18 @@ let EE;
 let PassThrough;
 let createReadableStreamAsyncIterator;
 
-function isIncoming(stream) {
-  return (
-    stream.socket &&
-    typeof stream.complete === 'boolean' &&
-    ArrayIsArray(stream.rawTrailers) &&
-    ArrayIsArray(stream.rawHeaders)
-  );
-}
-
-function isOutgoing(stream) {
-  return (
-    stream.socket &&
-    typeof stream.setHeader === 'function'
-  );
-}
-
-function destroyer(stream, reading, writing, final, callback) {
-  const _destroy = once((err) => {
-    if (!err && (isIncoming(stream) || isOutgoing(stream))) {
-      // http/1 request objects have a coupling to their response and should
-      // not be prematurely destroyed. Assume they will handle their own
-      // lifecycle.
-      return callback();
-    }
+function destroyer(stream, reading, writing, callback) {
+  callback = once(callback);
 
-    if (!err && reading && !writing && stream.writable) {
-      return callback();
-    }
-
-    if (err || !final || !stream.readable) {
-      destroyImpl.destroyer(stream, err);
-    }
-    callback(err);
+  let finished = false;
+  stream.on('close', () => {
+    finished = true;
   });
 
   if (eos === undefined) eos = require('internal/streams/end-of-stream');
   eos(stream, { readable: reading, writable: writing }, (err) => {
+    finished = !err;
+
     const rState = stream._readableState;
     if (
       err &&
@@ -78,14 +53,19 @@ function destroyer(stream, reading, writing, final, callback) {
       // eos will only fail with premature close on the reading side for
       // duplex streams.
       stream
-        .once('end', _destroy)
-        .once('error', _destroy);
+        .once('end', callback)
+        .once('error', callback);
     } else {
-      _destroy(err);
+      callback(err);
     }
   });
 
-  return (err) => _destroy(err || new ERR_STREAM_DESTROYED('pipe'));
+  return (err) => {
+    if (finished) return;
+    finished = true;
+    destroyImpl.destroyer(stream, err);
+    callback(err || new ERR_STREAM_DESTROYED('pipe'));
+  };
 }
 
 function popCallback(streams) {
@@ -204,7 +184,7 @@ function pipeline(...streams) {
 
     if (isStream(stream)) {
       finishCount++;
-      destroys.push(destroyer(stream, reading, writing, !reading, finish));
+      destroys.push(destroyer(stream, reading, writing, finish));
     }
 
     if (i === 0) {
@@ -262,7 +242,7 @@ function pipeline(...streams) {
         ret = pt;
 
         finishCount++;
-        destroys.push(destroyer(ret, false, true, true, finish));
+        destroys.push(destroyer(ret, false, true, finish));
       }
     } else if (isStream(stream)) {
       if (isReadable(ret)) {
diff --git a/test/parallel/test-stream-pipeline.js b/test/parallel/test-stream-pipeline.js
@@ -13,6 +13,7 @@ const {
 const assert = require('assert');
 const http = require('http');
 const { promisify } = require('util');
+const net = require('net');
 
 {
   let finished = false;
@@ -916,7 +917,7 @@ const { promisify } = require('util');
   const src = new PassThrough({ autoDestroy: false });
   const dst = new PassThrough({ autoDestroy: false });
   pipeline(src, dst, common.mustCall(() => {
-    assert.strictEqual(src.destroyed, true);
+    assert.strictEqual(src.destroyed, false);
     assert.strictEqual(dst.destroyed, false);
   }));
   src.end();
@@ -1118,3 +1119,95 @@ const { promisify } = require('util');
     assert.strictEqual(closed, true);
   }));
 }
+
+{
+  const server = net.createServer(common.mustCall((socket) => {
+    // echo server
+    pipeline(socket, socket, common.mustCall());
+    // 13 force destroys the socket before it has a chance to emit finish
+    socket.on('finish', common.mustCall(() => {
+      server.close();
+    }));
+  })).listen(0, common.mustCall(() => {
+    const socket = net.connect(server.address().port);
+    socket.end();
+  }));
+}
+
+{
+  const d = new Duplex({
+    autoDestroy: false,
+    write: common.mustCall((data, enc, cb) => {
+      d.push(data);
+      cb();
+    }),
+    read: common.mustCall(() => {
+      d.push(null);
+    }),
+    final: common.mustCall((cb) => {
+      setTimeout(() => {
+        assert.strictEqual(d.destroyed, false);
+        cb();
+      }, 1000);
+    }),
+    destroy: common.mustNotCall()
+  });
+
+  const sink = new Writable({
+    write: common.mustCall((data, enc, cb) => {
+      cb();
+    })
+  });
+
+  pipeline(d, sink, common.mustCall());
+
+  d.write('test');
+  d.end();
+}
+
+{
+  const server = net.createServer(common.mustCall((socket) => {
+    // echo server
+    pipeline(socket, socket, common.mustCall());
+    socket.on('finish', common.mustCall(() => {
+      server.close();
+    }));
+  })).listen(0, common.mustCall(() => {
+    const socket = net.connect(server.address().port);
+    socket.end();
+  }));
+}
+
+{
+  const d = new Duplex({
+    autoDestroy: false,
+    write: common.mustCall((data, enc, cb) => {
+      d.push(data);
+      cb();
+    }),
+    read: common.mustCall(() => {
+      d.push(null);
+    }),
+    final: common.mustCall((cb) => {
+      setTimeout(() => {
+        assert.strictEqual(d.destroyed, false);
+        cb();
+      }, 1000);
+    }),
+    // `destroy()` won't be invoked by pipeline since
+    // the writable side has not completed when
+    // the pipeline has completed.
+    destroy: common.mustNotCall()
+  });
+
+  const sink = new Writable({
+    write: common.mustCall((data, enc, cb) => {
+      cb();
+    })
+  });
+
+  pipeline(d, sink, common.mustCall());
+
+  d.write('test');
+  d.end();
+}
