[fortmarek]

Summary

Releases were gated by Build Once.xcframework, which built five static libraries one after another (82 to 94 min), while every release build compiled Once twice from a cold cache.

• Build XCFramework slices in parallel: the macOS slices come from the darwin build jobs, which already compiled their dependencies, each iOS slice builds in its own job, and a short job assembles, signs, and notarizes the framework.
• Run the release macOS jobs on Tuist runners with a cache volume for Cargo output.
• Use the Tuist remote cache for release builds when sign-in and a probe lookup succeed, falling back to the local cache otherwise.
• Key Rust actions by the host C library on Linux, so the remote cache no longer serves a build script linked against glibc 2.39 to the Ubuntu 22.04 runner. This brings the Linux release builds onto the remote cache.
• Build the bootstrap Once with the latest released Once through the remote cache, falling back to a Cargo build when the released Once cannot build the current graph. Compile the Cargo fallback without optimizing Once's own crates.
• Use the Tuist remote cache for the Windows release graph build in the once workflow.

Measurements

End-to-end Release runs on test branches with publishing disabled, measured from run start until publishing would begin:

Run	Start to publish-ready
Before, ci/release-e2e-before (main)	107 min (Build Once.xcframework 94 min, darwin builds 36 min, Windows 47 min)
After, cold caches, Cargo bootstrap	Linux x86_64 failed on the glibc issue fixed here; other jobs finished in 43 min (Windows)
After, warm, with a once-core change, Cargo bootstrap	30 min (Windows 28.5 min, of which 14 min is the Cargo bootstrap)
After, cold caches for the new action keys, bootstrap built with Once	40 min (Windows)
After, warm, with a once-core change, bootstrap built with Once	24 min (Windows 21.5 min: bootstrap 5.4 min, release build 11.8 min)

Notes

• Release artifacts can now include remote cache entries written by same-repository branches.
• A remote cache outage after the probe still fails the build; a rerun recovers.
• Until a release includes the host C library key, the released Once on Linux x86_64 can still pick up a build script linked against a newer glibc, so that job falls back to the Cargo bootstrap (about 30 seconds lost). The first release from this branch removes the fallback.