Undefined subjects in subscription (use stream name + consumer to subscribe instead of subject)

[scottf]

Overview

Should subscription api allow null/empty/undefined subject when both stream and durable [consumer] name are supplied? Only in case of bind? This would also require that the durable exists, otherwise the subscription would fail for lack of subject.

The behavior will be documented in ADR-15

Clients and Tools

• [x] Go @piotrpio
• [x] Java @scottf - this client allows undefined subjects in bind
• [ ] JavaScript @aricart
• [x] .Net @ColinSullivan1 @scottf - this client allows undefined subjects in bind
• [x] C done by kozlovic
• [ ] Python @wallyqs
• [ ] Ruby @wallyqs
• [x] Rust @Jarema

Other Tasks

• [ ] docs.nats.io updated
• [ ] Update ADR to Implemented
• [x] Update client features spreadsheet

Client authors please update with your progress. If you open issues in your own repositories as a result of this request, please link them to this one by pasting the issue URL in a comment or main issue description.

[scottf]

As an example, the Java / .net client allow the user to skip the subject when they indicate bind.

[aricart]

The jetstream subscribe() requires a subject in JavaScript. so even if you are doing a bind/etc the subject provided in the subscribe API is matched to the consumer if the stream/durable are specified.

[Jarema]

JetStream simplified API addresses this issue.

Since it's already implemented in Rust, I'm ticking Rust box :).

[piotrpio]

Go client requires a subject to be provided only if neither Bind() nor BindStream() are used.