Improved bottle reproducibility

[MikeMcQuaid]

Provide a detailed description of the proposed feature

With brew bottle --json --only-json-tab we now have the ability to create reproducible bottles. This has been demonstrated by Homebrew/homebrew-core@c6180a0

Will add to this issue as issues are discovered:

• created files are owned as brew:admin on our ARM64 Big Sur CI boxes and brew:staff elsewhere
  • should be relatively easy, one-time job to update this on our workers so they are consistent (in either direction)
• /usr/local/share/ is not replaced with @@HOMEBREW_PREFIX@@/share/ on ARM64 Big Sur CI boxes (and likely wouldn't be on Linux) but is on x86_64 macOS CI boxes. This happens even when it's not actually a reference to the Homebrew prefix but just the default system paths. This likely affects a non-trivial number of bottles.
  • not sure how best to handle this (or even if we can)

What is the motivation for the feature?

• Reducing the storage impact of bottles in GitHub Packages and in the local cache (when upgrading macOS versions).
• The motivation for https://reproducible-builds.org

How will the feature be relevant to at least 90% of Homebrew users?

It probably won't be!

What alternatives to the feature have been considered?

The status quo.

[MikeMcQuaid]

(If you want to find more issues like this: use diffoscope with the two downloaded bottle tarball files as input)

[MikeMcQuaid]

[ ] created files are owned as brew:admin on our ARM64 Big Sur CI boxes and brew:staff elsewhere

• should be relatively easy, one-time job to update this on our workers so they are consistent (in either direction)

Should be fixed in #11150 (without needing to update the workers).

[MikeMcQuaid]

Closing this as consider it generally done.