Comment by jessaustin
11 years ago
...you're making your code incompatible with anything that requires a higher or lower version of that library.
Actually that's not correct when using node/npm (or anything else in the ecosystem like browserify). That is one of the impressive things about this platform: any number of different versions of the same module can be required by the same app. It would be nuts to do that in your own code, but as long as the craziness is in your dependencies it really doesn't matter.
And that kind of works in a dynamic language. You could make it work in a statically-typed language, but then the problems will become more apparent. If X depends on Y and Z1 and Y depends on Z2, and Y exposes an object created by Z2 in its public API, the X developers might look at the Y api docs and try to call Z1 functions on that Z2 object! Worst of all, it might very well work in the normal cases, and the issue might not be noticed until it's in production.
Using multiple versions of the same library is code smell. It's a stability issue, a security issue, a complexity-breeder, and an absolute nightmare for packagers.
And npm allows it to happen silently.
Yeah I'm sure it sucks for distro packagers. Why are they using npm, though? It's not designed for their use case.
Actually though you're just talking about some bugs in X, or possibly some design flaws in Y. Passing [EDIT, because bare objects are fine:] class instances around like that is the real code smell. So much coupling, so little cohesion. We call them "modules" because we like modularity.
It's not that packagers are using npm. It's that they might want to package a node application for their distro's package system, and now they have to sift through thousands of npm packages (already a nightmare). They can't just make a system package for every npm package, not just because that would violate packaging guidelines for any reasonable distro, but because one project can pull in multiple versions of a single package. The Nix and Guix crews can handle that (and that they can is as much of a bug as it is a feature).
There is no clean way of packaging a typical node application.
Passing class instances around like that is the real code smell.
Often, yes, but not always. Allowing fine-grained control over performance is one good reason that a library might expose class instances from one of its dependencies.
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...and now you can have all the bugs introduced in all the versions of the library! Yay!
Or you could have all the bugs introduced in everyone's hand-rolled implementations of it. I'll take multiple versions of the library instead. It's much easier to track issues and submit patches to update their dependencies later.
> Or you could have all the bugs introduced in everyone's hand-rolled implementations of it.
Only one buggy implementation per project. Compare this to including the same library in dozen different versions, because dependencies have their own dependencies. And you can neither track the versions nor update them.