How to get latest (pre)release of Lean

Stream: Is there code for X?

[Asei Inoue]

I want to get latest (pre)release of Lean as String. (ex. v4.9.1, v4.10.0-rc2, ...)
This is for lean-update action.

I used to implement this as follows:

  LATEST_LEAN=$(gh release list --repo leanprover/lean4 --limit 1 | awk '{print $1}')
  echo "The latest release/prerelase is: $LATEST_LEAN"
  echo "leanprover/lean4:$LATEST_LEAN" > lean-toolchain

almost always this works, but this sometimese fails.
For example, at Jul 11, this script would get v4.9.1 as the latest release, but actually the latest was v4.10.0-rc2.
see : https://github.com/oliver-butterley/lean-update/issues/26

Is there an easy way to get the latest release?

[Kim Morrison]

I don't know of a way to ask Github, besides getting the whole list, parsing the version identifiers, sorting them (appropriately!), and taking the last one.

[Kim Morrison]

Someone should write a tiny semver library in Lean!

[Joachim Breitner]

You mean https://github.com/leanprover/release-index and https://release.lean-lang.org/stable.json etc?

[Joachim Breitner]

(I guess you still need to sort them.)

[Yury G. Kudryashov]

gh can return all releases, but it sorts them by date, not by version number.

[Asei Inoue]

I made a simple lib for this.

https://github.com/Seasawher/Semver.lean