Using <= for every dependency in case of following semantic versioning idea

Question

As Semantic Versioning (and common sense) declares - the major version is incremented in case if non backward compatible change is introduced.

Now let's assume we have a project called Project that has a current version 1.0.42 and a library Lib it depends on that is of a 2.1.3 version at the moment.

Does that mean that following semver ideology we should constraint the dependency of the Project to be Depends: Lib (< 3)?

From my experience - no one does that, but I find it semantically correct and very self-descriptive.

What do you think of this?

• user7043: Technically, Lib (>= 2.x, < 3) where x is the minor version that introduced the latest feature you rely on (perhaps a patch version too if you depend on a recent bug fix) would be safer, as it rules out 2.(x-1) which your code wouldn't work with.
• zerkms: @delnan: would you like to post it as an answer?
• Bart van Ingen Schenau: My guess is that semantic versioning isn't followed widely and strictly enough for people to generally depend on it.
• zerkms: @Bart van Ingen Schenau: you still need to follow some convention
• Bart van Ingen Schenau: @zerkms: As author of Project, does the fact that Lib has version2.1.3 guarantee you that the authors of Lib strictly follow semantic versioning? Perhaps they don't and remove a function in version 2.2.

Answer 1

The RubyGems package management system has the pessimistic version constraint for precisely this reason:

~> 1.2.3

means "chop off the last component of the version number and treat it is a wildcard, but don't use a version less than specified", IOW

~> 1.2.3

means

1.2.* && >= 1.2.3

and

~> 1.2.3.4

means

1.2.3.* && >= 1.2.3.4

In other words, it means: any version at least as new as the one that was specified, but only within the same "category". So, if you specify a bugfix release, you will get newer bugfix releases but no new minor version. If you specify a minor verso, you will get newer minor versions but no new major version.