We are making some changes to the Buildpack API so that app environment is available to all builds. The
user-env-compile labs feature, which made the app environment available during build, will be retired. Instead, an additional third argument will be passed to the
compile script of all builds run on Heroku:
bin/compile BUILD_DIR CACHE_DIR ENV_DIR
ENV_DIR argument is the location of a directory that contains a file for each of the application’s configuration variables. Additional details are available in the Buildpack API Dev Center article
Buildpacks maintained by Heroku have been updated and we have reached out to maintainers of 3rd party buildpacks in use by apps with
user-env-compile enabled. We have also reached out to active users with apps that have
user-env-compile enabled if they are using buildpacks that have not been updated.
We are rolling out the behavior starting today. For users relying on
user-env-compile and non-updated buildpacks,
user-env-compile will be retired starting two weeks from now. Users needing more time to migrate can open a support ticket.