Tag Driven Releasing

Background Reading

Initial setup for the repository

To configure tag driven releases from Travis CI.

Generate a key pair for this repository with ./admin/genKeyPair.sh. Edit .travis.yml and admin/build.sh as prompted.
Publish the public key to https://pgp.mit.edu
Store other secrets as encrypted environment variables with admin/encryptEnvVars.sh. Edit .travis.yml as prompted.
Edit .travis.yml to use ./admin/build.sh as the build script, and edit that script to use the tasks required for this project.
Edit build.sbt's scalaVersionsByJvm in ThisBuild to select Scala and JVM version combinations that will be used for publishing.

It is important to add comments in .travis.yml to identify the name of each environment variable encoded in a :secure section.

After these steps, your .travis.yml should contain config of the form:

language: scala

env:
  global:
    # PGP_PASSPHRASE
    - secure: "XXXXXX"
    # SONA_USER
    - secure: "XXXXXX"
    # SONA_PASS
    - secure: "XXXXXX"

script: admin/build.sh

jdk:
  - oraclejdk8
  - openjdk11

notifications:
  email:
    - a@b.com

If Sonatype credentials change in the future, step 3 can be repeated without generating a new key.

Testing

Follow the release process below to create a dummy release (e.g., v0.1.0-TEST1). Confirm that the release was staged to Sonatype but do not release it to Maven central. Instead, drop the staging repository.

Performing a release

Create a GitHub "Release" with a corresponding tag (e.g., v0.1.1) via the GitHub web interface.
The release will be published using the Scala and JVM version combinations specified in scalaVersionsByJvm in build.sbt.
- If you need to release against a different Scala version, include the Scala version and the JVM version to use in the tag name, separated by #s (e.g., v0.1.1#2.13.0-M1#8). Note that the JVM version needs to be listed in .travis.yml for the build to run.
Travis CI will schedule a build for this release. Review the build logs.
Log into https://oss.sonatype.org/ and identify the staging repository.
Sanity check its contents.
Release staging repository to Maven and send out release announcement.