child_process: special handling of process.on('message')

[refack]

• Version: *
• Platform: *
• Subsystem: child_process

process.on('message');

has a special meaning in the context of IPC between parent and child. The problem is a 'message' event could be triggered other code, or listened to outside of IPC context, so we can not do any special treatment for it.
I suggest adding 'IPCMessage' that only the IPC channel can trigger, and registering a listener to would fail if an IPC channel was not established.
Ref: nodejs/help#693 (comment)
[edit]
The intention is to emit both events: message for backwards compatibility, and IPCMessage for a validated IPC only events.

[mscdex]

-1 That would unnecessarily break backwards compatibility for zero gain IMHO.

[refack]

-1 That would unnecessarily break backwards compatibility for zero gain IMHO.

@mscdex I mean emit both events (with proper checks). Should not break break compatibility, and allow for an opt-in stricter/guaranteed means of IPC.

[ORESoftware]

@refack but couldn't some evil actor just emit IPCMessage

process.emit('IPCMessage') even if it were not an IPC message?

in my code, I check for properties on the message object coming back to see if it's IPC related.

[refack]

@refack but couldn't some evil actor just emit IPCMessage
process.emit('IPCMessage') even if it were not an IPC message?
in my code, I check for properties on the message object coming back to see if it's IPC related.

As I see it the node internal code will have exclusivity on emitting IPCMessage. Probably need to inherit from EventEmitter and override the emit and the registerListener do validate IPCMessage events.
A really "evil actor" could probably monkey patch something, but that is true for most of the API, sometimes for the better (i.e. graceful-fs)

[mscdex]

I still don't see any worthwhile gain coming from such changes.

[TimothyGu]

(removing "good first contribution" tag as there isn't yet a consensus)

[bnoordhuis]

Also -1. Adds complexity and overhead for unclear benefit and feels a bit like a solution in search of a problem.

[refack]

Closing for lack of consensus 🤷‍♂️