What are these massive unprocessed_archive.zip files in var/tmp/_bazel_me/?

[tinder-tannerbennett]

I was poking around in my company's project's build folder, and I'm curious what these unprocessed_archive.zip files are in nearly every target's build folder, such as this:

/private/var/tmp/_bazel_tanner/8693a7…/execroot/<project>/bazel-out/ios_sim_arm64-fastbuild-ios-sim_arm64-min15.0-applebin_ios-ST-24be3700a9bb/bin/Projects/Modules/.../LibraryTests/<Suite>_LibraryTests.__internal__.__test_bundle-intermediates/unprocessed_archive.zip

All in all, my build folder is about 150 GB, and most of it are these unprocessed_archive.zip files. What are they exactly? And can they be deleted once created, to free up space if need be? Or will they be re-created if deleted so you effectively can't delete them?

(I asked one of our devex engineers and was told to post here about it; if this is the wrong place and this isn't a rules_apple artifact, my apologies!)

[luispadron]

These are created when not using --@build_bazel_rules_apple//apple/build_settings:use_tree_artifacts_outputs=true (see: #2545 description for some more info).

Also see:

rules_apple/apple/build_settings/build_settings.bzl

Line 37 in 7eca118

Enables Bazel's tree artifacts for Apple bundle rules (instead of archives).

I'd love to optimize these or flip the flag but it's non-trivial from what I understand. @keith @brentleyjones thoughts?

[luispadron]

In our project:

Without usage of the use_tree_artifacts_outputs flag (default):

bin/Code/Apps/App/App_archive-root/Payload/App.app (732 MB)
bin/Code/Apps/App/App-intermediates/unprocessed_archive.zip (732 MB)
bin/Code/Apps/App/App.ipa (740 MB)

With use_tree_artifacts_outputs flag:

bin/Code/Apps/App/App_archive-root/Payload/App.app (732 MB)

[tinder-tannerbennett]

Awesome, thank you!