net: support passing undefined to listen()

For consistency with 4.x and 8.x.
This commit also contains a forward port of
#14232 to confirm that 4.x and 6.x
behave identically with respect to the port argument.
Backport-PR-URL: #14234
PR-URL: #14234
Refs: #14205
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

Author: sam-github

lib/net.js

@@ -1342,7 +1342,7 @@ Server.prototype.listen = function() {
 self.once('listening',lastArg);
 }
 
-varport=toNumber(arguments[0]);
+varport=typeofarguments[0]==='undefined' ? 0 : toNumber(arguments[0]);
 
 // The third optional argument is the backlog size.
 // When the ip is omitted it can be the second argument.

test/parallel/test-net-listen-port-option.js

@@ -26,3 +26,47 @@ net.Server().listen({ port: '' + common.PORT }, close);
 net.Server().listen({port: port},common.fail);
 },/invalidlistenargument/i);
 });
+
+// Repeat the tests, passing port as an argument, which validates somewhat
+// differently.
+
+net.Server().listen(undefined,close);
+net.Server().listen('0',close);
+
+// 'nan', skip, treated as a path, not a port
+//'+Infinity', skip, treated as a path, not a port
+//'-Infinity' skip, treated as a path, not a port
+
+// 4.x treats these as 0, but 6.x treats them as invalid numbers.
+[
+-1,
+123.456,
+0x10000,
+1/0,
+-1/0,
+].forEach(function(port){
+assert.throws(function(){
+net.Server().listen(port,common.fail);
+},/"port"argumentmustbe>=0and<65536/i);
+});
+
+// null is treated as 0
+net.Server().listen(null,close);
+
+// false/true are converted to 0/1, arguably a bug, but fixing would be
+// semver-major. Note that true fails when port 1 low can't be listened on by
+// unprivileged processes (Linux) but the listen does succeed on some Windows
+// versions.
+net.Server().listen(false,close);
+
+(function(){
+constdone=common.mustCall(function(err){
+if(err)
+returnassert.strictEqual(err.code,'EACCES');
+
+assert.strictEqual(this.address().port,1);
+this.close();
+});
+
+net.Server().listen(true).on('error',done).on('listening',done);
+})();