Make some global variables part of the public API

Library/Homebrew/.rubocop.yml

@@ -65,6 +65,7 @@ Style/Documentation:
     - livecheck/strategy/yaml.rb
     - os.rb
     - resource.rb
+    - startup/config.rb
     - utils/inreplace.rb
     - utils/shebang.rb
     - utils/string_inreplace_extension.rb

Library/Homebrew/startup/config.rb

@@ -3,17 +3,39 @@
 
 raise "HOMEBREW_BREW_FILE was not exported! Please call bin/brew directly!" unless ENV["HOMEBREW_BREW_FILE"]
 
-# Path to `bin/brew` main executable in `HOMEBREW_PREFIX`
-# Used for e.g. permissions checks.
-HOMEBREW_ORIGINAL_BREW_FILE = Pathname(ENV.fetch("HOMEBREW_ORIGINAL_BREW_FILE")).freeze
-
-# Path to the executable that should be used to run `brew`.
-# This may be HOMEBREW_ORIGINAL_BREW_FILE or HOMEBREW_BREW_WRAPPER.
+# The path to the executable that should be used to run `brew`.
+# This may be HOMEBREW_ORIGINAL_BREW_FILE or HOMEBREW_BREW_WRAPPER depending on
+# the system configuration. Favour this instead of running `brew` and expecting
+# it to be in the `PATH`.
+# @api public
 HOMEBREW_BREW_FILE = Pathname(ENV.fetch("HOMEBREW_BREW_FILE")).freeze
 
-# Where we link under
+# Where Homebrew is installed and files are linked to.
+# @api public
 HOMEBREW_PREFIX = Pathname(ENV.fetch("HOMEBREW_PREFIX")).freeze
 
+# Where Homebrew stores built formulae packages, linking (non-keg-only) ones
+# back to `HOMEBREW_PREFIX`.
+# @api public
+HOMEBREW_CELLAR = Pathname(ENV.fetch("HOMEBREW_CELLAR")).freeze
+
+# Where Homebrew downloads (bottles, source tarballs, casks etc.) are cached.
+# @api public
+HOMEBREW_CACHE = Pathname(ENV.fetch("HOMEBREW_CACHE")).freeze
+
+# Where Homebrew stores temporary files.
+# We use `/tmp` instead of `TMPDIR` because long paths break Unix domain
+# sockets.
+# @api public
+HOMEBREW_TEMP = Pathname(ENV.fetch("HOMEBREW_TEMP")).then do |tmp|
+  tmp.mkpath unless tmp.exist?
+  tmp.realpath
+end.freeze
+
+# Path to `bin/brew` main executable in `HOMEBREW_PREFIX`
+# Used for e.g. permissions checks.
+HOMEBREW_ORIGINAL_BREW_FILE = Pathname(ENV.fetch("HOMEBREW_ORIGINAL_BREW_FILE")).freeze
+
 # Where `.git` is found
 HOMEBREW_REPOSITORY = Pathname(ENV.fetch("HOMEBREW_REPOSITORY")).freeze
 
@@ -35,27 +57,15 @@
 # Where we store lock files
 HOMEBREW_LOCKS = (HOMEBREW_PREFIX/"var/homebrew/locks").freeze
 
-# Where we store built products
-HOMEBREW_CELLAR = Pathname(ENV.fetch("HOMEBREW_CELLAR")).freeze
-
 # Where we store Casks
 HOMEBREW_CASKROOM = Pathname(ENV.fetch("HOMEBREW_CASKROOM")).freeze
 
-# Where downloads (bottles, source tarballs, etc.) are cached
-HOMEBREW_CACHE = Pathname(ENV.fetch("HOMEBREW_CACHE")).freeze
-
 # Where formulae installed via URL are cached
 HOMEBREW_CACHE_FORMULA = (HOMEBREW_CACHE/"Formula").freeze
 
 # Where build, postinstall and test logs of formulae are written to
 HOMEBREW_LOGS = Pathname(ENV.fetch("HOMEBREW_LOGS")).expand_path.freeze
 
-# Must use `/tmp` instead of `TMPDIR` because long paths break Unix domain sockets
-HOMEBREW_TEMP = Pathname(ENV.fetch("HOMEBREW_TEMP")).then do |tmp|
-  tmp.mkpath unless tmp.exist?
-  tmp.realpath
-end.freeze
-
 # Where installed taps live
 HOMEBREW_TAP_DIRECTORY = (HOMEBREW_LIBRARY/"Taps").freeze