Heroku CLI v9: Infrastructure Upgrades and oclif Transition

Summary

Heroku CLI 9.0.0 is an architectural upgrade centered on moving all core commands from a partly legacy structure to oclif. Core commands are consolidated into one package, while improved unit and integration coverage, telemetry, and a simpler automated release process support contribution, maintenance, and pre-release testing. The oclif migration provides a modular command architecture with plugin support and is intended to make command behavior more consistent, maintenance easier, and provide better scalability. Users should expect breaking changes including altered whitespace, newlines, table formatting, colors, argument ordering, flag removals, and a required separator for additional flags; deprecated commands including outbound-rules, pg:repoint, orgs:default, certs:chain, certs:key were removed. Changes apply to core commands, not separately installed plugins, and the release can be installed with heroku update.

Takeaways

1. 1

   All core Heroku CLI commands now use oclif, replacing the previous mixture of oclif and pre-oclif legacy architecture.

2. 2

   CLI 9.0.0 consolidates core commands into one package and improves testing and release automation, including easier pre-release distribution.

3. 3

   The upgrade changes output formatting and some command interfaces, removes several deprecated commands, and requires a separator for additional flags; separately installed plugins are unaffected.