net: make readable/writable start as true

`net.Socket` is slightly breaking stream invariants by
having readable/writable going from `false` to `true`.
Streams assume that readable/writable starts out `true`
and then goes to `false` through `push(null)`/`end()`
after which it never goes back to `true`, e.g. once a
stream is `writable == false` it is assumed it will
never become `true`.

This PR changes 2 things:

Unless explicitly set to `false` through options:

- starts as `readable`/`writable` `true` by default.
- uses `push(null)`/`end()` to set `readable`/`writable`
  to `false`. Note that this would cause the socket to
  emit the `'end'`/`'finish'` events, which it did not
  do previously.

In the case it is explicitly set to `false` through
options` it is assumed to never become `true`.

PR-URL: https://github.com/nodejs/node/pull/32272
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-net-socket-constructor.js

@@ -27,12 +27,12 @@ function test(sock, readable, writable) {
 }
 
 if (cluster.isMaster) {
-  test(undefined, false, false);
+  test(undefined, true, true);
 
   const server = net.createServer(common.mustCall((socket) => {
     socket.unref();
     test(socket, true, true);
-    test({ handle: socket._handle }, false, false);
+    test({ handle: socket._handle }, true, true);
     test({ handle: socket._handle, readable: true, writable: true },
          true, true);
     server.close();
@@ -45,7 +45,7 @@ if (cluster.isMaster) {
       socket.end();
     }));
 
-    test(socket, false, true);
+    test(socket, true, true);
   }));
 
   cluster.setupMaster({
@@ -58,8 +58,8 @@ if (cluster.isMaster) {
     assert.strictEqual(signal, null);
   }));
 } else {
-  test(4, false, false);
-  test({ fd: 5 }, false, false);
+  test(4, true, true);
+  test({ fd: 5 }, true, true);
   test({ fd: 6, readable: true, writable: true }, true, true);
   process.disconnect();
 }

test/parallel/test-net-socket-setnodelay.js

@@ -13,28 +13,32 @@ const genSetNoDelay = (desiredArg) => (enable) => {
 // setNoDelay should default to true
 let socket = new net.Socket({
   handle: {
-    setNoDelay: common.mustCall(genSetNoDelay(true))
+    setNoDelay: common.mustCall(genSetNoDelay(true)),
+    readStart() {}
   }
 });
 socket.setNoDelay();
 
 socket = new net.Socket({
   handle: {
-    setNoDelay: common.mustCall(genSetNoDelay(true), 1)
+    setNoDelay: common.mustCall(genSetNoDelay(true), 1),
+    readStart() {}
   }
 });
 truthyValues.forEach((testVal) => socket.setNoDelay(testVal));
 
 socket = new net.Socket({
   handle: {
-    setNoDelay: common.mustNotCall()
+    setNoDelay: common.mustNotCall(),
+    readStart() {}
   }
 });
 falseyValues.forEach((testVal) => socket.setNoDelay(testVal));
 
 socket = new net.Socket({
   handle: {
-    setNoDelay: common.mustCall(() => {}, 3)
+    setNoDelay: common.mustCall(() => {}, 3),
+    readStart() {}
   }
 });
 truthyValues.concat(falseyValues).concat(truthyValues)
@@ -44,7 +48,8 @@ truthyValues.concat(falseyValues).concat(truthyValues)
 // In the case below, if it is called an exception will be thrown
 socket = new net.Socket({
   handle: {
-    setNoDelay: null
+    setNoDelay: null,
+    readStart() {}
   }
 });
 const returned = socket.setNoDelay(true);