Note that this is a sliiiightly modified SemVer: in SemVer, these three things would conflict. It would be strict SemVer if uno depended on ~>1.3, and dos on ~>1.4.
We hypothesize that this difference works better for AOT compiled languages. And since it's pre-1.0, it's all good. This is the 'we'll watch this closely and adjust' from the email: it might not be okay.
When you declare an x.y.z dependency, tools that use SemVer (like Bundler, which is the biggest influence on Cargo) assume x.y.(>z). So, a 1.4.12 dependency says "Anything greater than 1.4.12, but less than 1.5.0."
When you declare an x.y dependency, tools that use SemVer assumes x.(>y). So, a 1.4 dependency says "Anything greater than 1.4.anything, but less than 2.anything.anything".
This is assuming the ~> operator, if it was =, it would ONLY be 1.14.2, which is even more restrictive.
The project _should_ work, which is why Cargo is using this modified version of ~>.
Comments
Note that this is a sliiiightly modified SemVer: in SemVer, these three things would conflict. It would be strict SemVer if uno depended on ~>1.3, and dos on ~>1.4.
We hypothesize that this difference works better for AOT compiled languages. And since it's pre-1.0, it's all good. This is the 'we'll watch this closely and adjust' from the email: it might not be okay.
Why would uno not work on 1.4?
When you declare an x.y.z dependency, tools that use SemVer (like Bundler, which is the biggest influence on Cargo) assume x.y.(>z). So, a 1.4.12 dependency says "Anything greater than 1.4.12, but less than 1.5.0."
When you declare an x.y dependency, tools that use SemVer assumes x.(>y). So, a 1.4 dependency says "Anything greater than 1.4.anything, but less than 2.anything.anything".
This is assuming the ~> operator, if it was =, it would ONLY be 1.14.2, which is even more restrictive.
The project _should_ work, which is why Cargo is using this modified version of ~>.