cluster: fix debugging port collision

[Ajido]

Fixing an issue that giving a debugging option including a hostname
stop the cluster worker by EADDRINUSE.

Checklist

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

Affected core subsystem(s)

src, cluster, test

[cjihrig]

This will match flags that specify a host, but it seems like the host would then be lost when the flag is rewritten for the worker process a few lines down.

[Ajido]

Thanks. I'm thinking about addding process._debugHostname to avoid complex regex, what do you think?

diff --git a/lib/internal/cluster/master.js b/lib/internal/cluster/master.js
index c7b06b8..2a7379b 100644
--- a/lib/internal/cluster/master.js
+++ b/lib/internal/cluster/master.js
@@ -124,7 +124,7 @@ function createWorkerProcess(id, env) {
         ++debugPortOffset;
       }

-      execArgv[i] = match[1] + '=' + debugPort;
+      execArgv[i] = match[1] + '=' + process._debugHostname + ':' + debugPort;
     }
   }

diff --git a/src/node.cc b/src/node.cc
index c241f73..f091ac7 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -3361,6 +3361,8 @@ void SetupProcessObject(Environment* env,
                              DebugPortSetter,
                              env->as_external()).FromJust());

+  READONLY_PROPERTY(process, "_debugHostname", OneByteString(env->isolate(), debug_options.host_name().c_str()));
+
   // define various internal methods
   env->SetMethod(process,
                  "_startProfilerIdleNotifier",

[bnoordhuis]

Superseded by #13619. Thanks for the pull request though.