diff --git a/Library/Homebrew/brew.rb b/Library/Homebrew/brew.rb
index 290b7a3db8..ab1a31e3b1 100644
--- a/Library/Homebrew/brew.rb
+++ b/Library/Homebrew/brew.rb
@@ -22,24 +22,7 @@ if RUBY_X < REQUIRED_RUBY_X || (RUBY_X == REQUIRED_RUBY_X && RUBY_Y < REQUIRED_R
         "You're running #{RUBY_VERSION}."
 end
 
-# Also define here so we can rescue regardless of location.
-class MissingEnvironmentVariables < RuntimeError; end
-
-begin
-  require_relative "global"
-rescue MissingEnvironmentVariables => e
-  raise e if ENV["HOMEBREW_MISSING_ENV_RETRY"]
-
-  if ENV["HOMEBREW_DEVELOPER"]
-    $stderr.puts <<~EOS
-      Warning: #{e.message}
-      Retrying with `exec #{ENV["HOMEBREW_BREW_FILE"]}`!
-    EOS
-  end
-
-  ENV["HOMEBREW_MISSING_ENV_RETRY"] = "1"
-  exec ENV["HOMEBREW_BREW_FILE"], *ARGV
-end
+require_relative "global"
 
 begin
   trap("INT", std_trap) # restore default CTRL-C handler
diff --git a/Library/Homebrew/startup/config.rb b/Library/Homebrew/startup/config.rb
index 26470cc464..0439e8ab03 100644
--- a/Library/Homebrew/startup/config.rb
+++ b/Library/Homebrew/startup/config.rb
@@ -4,29 +4,16 @@
 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`
-HOMEBREW_BREW_FILE = Pathname(ENV["HOMEBREW_BREW_FILE"]).freeze
-
-class MissingEnvironmentVariables < RuntimeError; end
-
-# Helper module for getting environment variables which must be set.
-#
-# @api private
-module EnvVar
-  def self.[](env)
-    raise MissingEnvironmentVariables, "#{env} was not exported!" unless ENV[env]
-
-    ENV.fetch(env)
-  end
-end
+HOMEBREW_BREW_FILE = Pathname(ENV.fetch("HOMEBREW_BREW_FILE")).freeze
 
 # Where we link under
-HOMEBREW_PREFIX = Pathname(EnvVar["HOMEBREW_PREFIX"]).freeze
+HOMEBREW_PREFIX = Pathname(ENV.fetch("HOMEBREW_PREFIX")).freeze
 
 # Where `.git` is found
-HOMEBREW_REPOSITORY = Pathname(EnvVar["HOMEBREW_REPOSITORY"]).freeze
+HOMEBREW_REPOSITORY = Pathname(ENV.fetch("HOMEBREW_REPOSITORY")).freeze
 
 # Where we store most of Homebrew, taps, and various metadata
-HOMEBREW_LIBRARY = Pathname(EnvVar["HOMEBREW_LIBRARY"]).freeze
+HOMEBREW_LIBRARY = Pathname(ENV.fetch("HOMEBREW_LIBRARY")).freeze
 
 # Where shim scripts for various build and SCM tools are stored
 HOMEBREW_SHIMS_PATH = (HOMEBREW_LIBRARY/"Homebrew/shims").freeze
@@ -44,19 +31,19 @@ HOMEBREW_PINNED_KEGS = (HOMEBREW_PREFIX/"var/homebrew/pinned").freeze
 HOMEBREW_LOCKS = (HOMEBREW_PREFIX/"var/homebrew/locks").freeze
 
 # Where we store built products
-HOMEBREW_CELLAR = Pathname(EnvVar["HOMEBREW_CELLAR"]).freeze
+HOMEBREW_CELLAR = Pathname(ENV.fetch("HOMEBREW_CELLAR")).freeze
 
 # Where downloads (bottles, source tarballs, etc.) are cached
-HOMEBREW_CACHE = Pathname(EnvVar["HOMEBREW_CACHE"]).freeze
+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(EnvVar["HOMEBREW_LOGS"]).expand_path.freeze
+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(EnvVar["HOMEBREW_TEMP"]).then do |tmp|
+HOMEBREW_TEMP = Pathname(ENV.fetch("HOMEBREW_TEMP")).then do |tmp|
   tmp.mkpath unless tmp.exist?
   tmp.realpath
 end.freeze