Automatically change compat entries on Pkg.update

[fonsp]

#3732 automatically adds compat entries when you add a package (to a named environment). The compat entry looks like:

[compat]
Example = "1.2.3"

My proposal is that compat entries should be changed automatically when you Pkg.update(). E.g. when you update to 1.3.0, the Project.toml should change to:

[compat]
Example = "1.3.0"

I believe that the same reasoning behind #3732 applies to the update situation.

(This same behaviour also happens in yarn and npm, where the install adds ^1.2.3 to the package.json, and upgrade changes it to ^1.3.0.)

[jakobnissen]

But then, if the author did check it was compatible with Example 1.2.3, wouldn't it be annoying that the compat was incorrectly changed?

[KristofferC]

This doesn't make sense to me? Why would you want to claim incompatible with previous versions just because you do an update?

[fonsp]

Thanks for the comments! To me it makes sense as a default, because update changes the version your are developing and testing with, and you might start depending on new functionality that was added in a minor update.

So as a "safe" default, 1.3.0 seems better after updating. To me it feels like the same argument for using 1.2.3 as the default for add, instead of just 1.

But I also see some practical issues like the one @jakobnissen brought up, where it is useful in the Julia ecosystem for packages to have wide compat ranges and we don't want to override those with stricter ones. npm is different here, since dependencies are not necessarily shared (two packages in one project can import different versions of the same transitive dep), so restricting compat bounds upwards is never really an issue there.