[Concept] Version-specific module dependencies

[RainOrigami]

This is a discussion. Add arguments, ideas and examples to this discussion so that together we can make an informed and sound decision on whether or not, and how to implement such a concept.

Currently module dependencies only target a module by their name. This may cause compatibility issues in cases where a dependent module changes its method signatures and becomes incompatible with modules that have a dependency to it.

Instead it was suggested that module dependencies should be version-dependent "just like npm".

Conceptionally a sound solution has to be created that covers all cases.

Requirements

Unique instancing

A module instance must only exist once per server.

Non-breaking updates

A non-breaking update to a module should allow all modules, that depend on it, to continue functioning.

[RainOrigami]

I argue against this for the following reasons

The current solution already supports this on an individual basis

If a module author really wants a specific version of a module, they can just validate the version in OnModulesLoaded and error and unload if it doesn't match.

Nothing gets solved when implementing this

The same issues of incompatibility already exist and will not get solved by a version-specific module dependency implementation.

The users will still have some modules that require A 1.0.0 and others that require A 1.1.0, which are incompatible with eachother.

It would only improve the visibility of such problems.

Can we really do better than established systems?

The system is based on umod. They don't have this solved. I don't think we're better than them.

I argue for this for the following reasons

This could just be solved by the website

When a module is uploaded and compiled against its dependencies, it can remark the versions of the dependencies if the compilation was successful.

Then, when uploading an update to a module, other modules that depend on it will get recompiled and checked for compatibility. If it fails, the website notes which version was the last successful version.

This would have the same effect of informing users which modules are compatible with which versions of their dependencies.