Bump JDK version (+ Scala version in docs) (#1662)

* Bump Scala and Java version in docs
* Bump JDK in github workflows, Dockerfile, Nix flake
* Update release notes

.github/workflows/main.yml

@@ -31,10 +31,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: Set up JDK 1.8
+      - name: Set up JDK 17
         uses: actions/setup-java@v1
         with:
-          java-version: 1.8
+          java-version: 17
       - name: Check formatting
         run: make fmt-check
 
@@ -49,11 +49,11 @@ jobs:
         operating-system: [ubuntu-latest, macos-latest]
     steps:
       - uses: actions/checkout@v2
-      - name: Set up JDK 1.8
+      - name: Set up JDK 17
         uses: actions/setup-java@v2
         with:
           distribution: temurin
-          java-version: 8
+          java-version: 17
       - name: Coursier cache
         uses: coursier/cache-action@v6
       - name: Set APALACHE_HOME env

.github/workflows/prepare-release.yml

@@ -28,7 +28,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-java@v1
         with:
-          java-version: 1.8
+          java-version: 17
       - name: Configure Git
         run: |
           git config --global user.name "$GITHUB_ACTOR"

.github/workflows/release.yml

@@ -19,7 +19,7 @@ jobs:
           fetch-depth: 2
       - uses: actions/setup-java@v1
         with:
-          java-version: 1.8
+          java-version: 17
       - name: Cut Release
         env:
           # NOTE: We must not use the default GITHUB_TOKEN for auth here,

UNRELEASED.md

@@ -10,12 +10,18 @@
          * Some bug fix, see #124
 
      DO NOT LEAVE A BLANK LINE BELOW THIS PREAMBLE -->
-### Features
+### Breaking changes
 
 * Experimental type unification over rows, new records, and variants, see #1646
 ### Breaking changes
 
  * Rename `--tuning` to `--tuning-options-file`, see #1579
+ * Recommended JDK version was bumped to JDK17, see #1662
+ * Add the option `--features` to enable experimental features, see #1648
+
+### Features
+
+ * Experimental type unification over rows, new records, and variants, see #1646
 
 ### Bug fixes
 

build.sbt

@@ -330,7 +330,7 @@ docker / dockerfile := {
   val readme = rootDir / "README.md"
 
   new Dockerfile {
-    from("eclipse-temurin:16")
+    from("eclipse-temurin:17")
 
     workDir(dwd)
 

docs/src/apalache/installation/jvm.md

@@ -1,8 +1,8 @@
 # Running in Java Virtual Machine
 
 You have to download and install a Java Virtual Machine first. For instance,
-[AdoptOpenJDK](https://adoptopenjdk.net/) should work (we tried Apalache with
-OpenJDK 11 and OpenJDK 15).
+[Eclipse Temurin][] should work (we recommend OpenJDK 17, the latest LTS
+release).
 
 Once you have installed Java, download the [latest
 release](https://github.com/informalsystems/apalache/releases) and unpack into
@@ -22,3 +22,5 @@ better, add the `./bin` directory to your `PATH` and run `apalache-mc`.
 If you would like to contribute a command-line script for running Apalache in
 Windows, please [open a pull
 request](https://github.com/informalsystems/apalache/blob/unstable/CONTRIBUTING.md#making-a-pull-request).
+
+[Eclipse Temurin]: https://adoptium.net/

docs/src/apalache/installation/source.md

@@ -1,9 +1,9 @@
 # Building from source
 
 1. Install `git`.
-2. Install [OpenJDK8][] or [Zulu JDK8][].
-   - Apalache currently requires Scala 2.12.0 so **you must install version 8 of
-     Java, otherwise Scala will not compile!** See the [compatibility table][].
+2. Install the [Eclipse Temurin][] or [Zulu][] build of OpenJDK 17.
+   - Apalache currently requires Scala 2.12.15, see [this table of compatible JDK versions][compatibility table].
+   - We recommend OpenJDK 17, the latest LTS release.
 3. Install [sbt][].
    - On Debian Linux or Ubuntu, [follow this guide](https://www.scala-sbt.org/1.x/docs/Installing-sbt-on-Linux.html#Ubuntu+and+other+Debian-based+distributions)
    - On Arch: `sudo pacman -Syu sbt`
@@ -32,8 +32,8 @@ repository, you have three options after running `make`:
 - Run `./bin/apalache-mc` directly.
 
 
-[OpenJDK8]: https://openjdk.java.net/install/
-[Zulu JDK8]: https://www.azul.com/downloads/zulu-community/?version=java-8-lts&architecture=x86-64-bit&package=jdk
+[Eclipse Temurin]: https://adoptium.net/
+[Zulu]: https://www.azul.com/downloads/?version=java-17-lts&package=jdk#download-openjdk
 [compatibility table]: https://docs.scala-lang.org/overviews/jdk-compatibility/overview.html
 [sbt]: https://www.scala-sbt.org/1.x/docs/Setup.html
 [direnv]: https://direnv.net/

docs/src/apalache/system-reqs.md

@@ -4,7 +4,7 @@ Every commit to [master](https://github.com/informalsystems/apalache) and
 [unstable](https://github.com/informalsystems/apalache/tree/unstable) is built
 with [GitHub
 actions](https://github.com/informalsystems/apalache/actions?query=branch%3Aunstable+workflow%3Abuild)
-on MacOS (JDK 1.8.0) and Linux (OpenJDK8). If you would like to run Apalache in
+on MacOS (JDK 17) and Linux (OpenJDK 17). If you would like to run Apalache in
 Windows, use a docker image. Check the [Docker
 manual](https://docs.docker.com/docker-for-windows/) and the section on [Using
 a docker image](./installation/docker.md) for details.

flake.nix

@@ -56,7 +56,7 @@
               # Built inputs are the packages that we provide in the PATH in the nix shell
               buildInputs = with pkgs; [
                 # Java / Scala
-                jdk8
+                jdk17_headless
                 scala_2_12
 
                 # Build