lib: make sure close the net server

[theanarkh]

If perform asynchronous operations in the listen function of net.js (execute dns.lookup or ask the main process to create a server), the server will not close properly.

The example is as follows.

// The "closed" TCP server will keep the process because // after calling close function, a TCP handle is created in the callback of `dns.lookup`.constnet=require('net');net.createServer().listen(9999,'localhost').close();

See

node/lib/net.js

Line 2092 in c08b797

functionlookupAndListen(self,port,address,backlog,exclusive,flags){

.

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[nodejs-github-bot]

Review requested:

• @nodejs/net

[mcollina]

lgtm

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/57509/

[lpinca]

Does it work if the user does something like this?

net.createServer().listen(9999,'localhost').close().listen(8888,'localhost');

[theanarkh]

Yes, close make the callback invalid of the first listen and the second listen executes normally.
I tested it locally, it ended up listening on port 8888 and just emit listening event once(before this PR, it will emit listening event twice).

[nodejs-github-bot]

Landed in 29ec7e9