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Performance can be very slow without the cache to prune the duplicate parts of the dependency tree so use the cache by default when running Formula#recursive_dependencies. All other usage of Dependency#expand in Homebrew/brew already uses the cache.

For blocks, I decided to create a temporary cache entry and purge it to avoid unnecessary memory consumption. Used the same naming scheme as FormulaInstaller. Not sure if any chance of collision (if so could add a SecureRandom.uuid or something else)

This should help with another slow down seen in:

• qt 6.9.3 homebrew-core#246844

Even on macOS with smaller dependency tree, there is a noticeable impact:

Benchmark 1: git checkout formula-recursive-dependencies-cache && brew reinstall -sv qt
  Time (mean ± σ):     14.824 s ±  1.606 s    [User: 10.861 s, System: 1.654 s]
  Range (min … max):   13.263 s … 18.121 s    10 runs

Benchmark 2: git checkout main && brew reinstall -sv qt
  Time (mean ± σ):     51.123 s ±  0.774 s    [User: 42.229 s, System: 6.600 s]
  Range (min … max):   49.952 s … 52.388 s    10 runs

Summary
  git checkout formula-recursive-dependencies-cache && brew reinstall -sv qt ran
    3.45 ± 0.38 times faster than git checkout main && brew reinstall -sv qt