Much better CTRL-C handling

Let's not show weird error messages when user interrupts during various stages of brew initialization.

Tested by doing `for x in $(brew search); do brew install $x; done` and pressing CTRL-C at random short intervals.

Library/Homebrew/build.rb

@@ -1,51 +1,54 @@
-#!/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
+#!/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby -W0
 
 # This script is called by formula_installer as a separate instance.
 # Rationale: Formula can use __END__, Formula can change ENV
 # Thrown exceptions are propogated back to the parent process over a pipe
 
-require 'global'
+STD_TRAP = trap("INT") { exit! 130 } # no backtrace thanks
 
 at_exit do
   # the whole of everything must be run in at_exit because the formula has to
   # be the run script as __END__ must work for *that* formula.
+  main
+end
 
-  error_pipe = nil
+require 'global'
 
-  begin
-    # The main Homebrew process expects to eventually see EOF on the error
-    # pipe in FormulaInstaller#build. However, if any child process fails to
-    # terminate (i.e, fails to close the descriptor), this won't happen, and
-    # the installer will hang. Set close-on-exec to prevent this.
-    # Whether it is *wise* to launch daemons from formulae is a separate
-    # question altogether.
-    if ENV['HOMEBREW_ERROR_PIPE']
-      require 'fcntl'
-      error_pipe = IO.new(ENV['HOMEBREW_ERROR_PIPE'].to_i, 'w')
-      error_pipe.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
-    end
+def main
+  # The main Homebrew process expects to eventually see EOF on the error
+  # pipe in FormulaInstaller#build. However, if any child process fails to
+  # terminate (i.e, fails to close the descriptor), this won't happen, and
+  # the installer will hang. Set close-on-exec to prevent this.
+  # Whether it is *wise* to launch daemons from formulae is a separate
+  # question altogether.
+  if ENV['HOMEBREW_ERROR_PIPE']
+    require 'fcntl'
+    error_pipe = IO.new(ENV['HOMEBREW_ERROR_PIPE'].to_i, 'w')
+    error_pipe.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
+  end
 
-    raise $! if $! # an exception was already thrown when parsing the formula
+  raise $! if $! # an exception was already thrown when parsing the formula
 
-    require 'hardware'
-    require 'keg'
+  trap("INT", STD_TRAP) # restore default CTRL-C handler
 
-    # Force any future invocations of sudo to require the user's password to be
-    # re-entered. This is in-case any build script call sudo. Certainly this is
-    # can be inconvenient for the user. But we need to be safe.
-    system "/usr/bin/sudo -k"
+  require 'hardware'
+  require 'keg'
 
-    install(Formula.factory($0))
-  rescue Exception => e
-    unless error_pipe.nil?
-      Marshal.dump(e, error_pipe)
-      error_pipe.close
-      exit! 1
-    else
-      onoe e
-      puts e.backtrace
-      exit! 2
-    end
+  # Force any future invocations of sudo to require the user's password to be
+  # re-entered. This is in-case any build script call sudo. Certainly this is
+  # can be inconvenient for the user. But we need to be safe.
+  system "/usr/bin/sudo -k"
+
+  install(Formula.factory($0))
+rescue Exception => e
+  unless error_pipe.nil?
+    Marshal.dump(e, error_pipe)
+    error_pipe.close
+    exit! 1
+  else
+    onoe e
+    puts e.backtrace
+    exit! 2
   end
 end
 

Library/Homebrew/formula_installer.rb

@@ -238,6 +238,7 @@ class FormulaInstaller
       Process.wait
       data = read.read
       raise Marshal.load(data) unless data.nil? or data.empty?
+      raise Interrupt if $?.exitstatus == 130
       raise "Suspicious installation failure" unless $?.success?
     end
 
@@ -266,15 +267,18 @@ class FormulaInstaller
     end
 
     keg = Keg.new(f.prefix)
-    keg.link
-  rescue Exception => e
-    onoe "The `brew link` step did not complete successfully."
-    puts "The formula built, but is not symlinked into #{HOMEBREW_PREFIX}."
-    puts "You can try again using `brew link #{f.name}`."
-    keg.unlink
 
-    ohai e, e.backtrace if ARGV.debug?
-    @show_summary_heading = true
+    begin
+      keg.link
+    rescue Exception => e
+      onoe "The `brew link` step did not complete successfully"
+      puts "The formula built, but is not symlinked into #{HOMEBREW_PREFIX}"
+      puts "You can try again using `brew link #{f.name}'"
+      ohai e, e.backtrace if ARGV.debug?
+      @show_summary_heading = true
+      ignore_interrupts{ keg.unlink }
+      raise unless e.kind_of? RuntimeError
+    end
   end
 
   def fix_install_names

Library/Homebrew/utils.rb

@@ -217,7 +217,7 @@ def inreplace path, before=nil, after=nil
 end
 
 def ignore_interrupts
-  std_trap = trap("INT") {}
+  std_trap = trap("INT") { puts "One sec, just cleaning up" }
   yield
 ensure
   trap("INT", std_trap)

bin/brew

@@ -1,6 +1,8 @@
 #!/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby -W0
 # -*- coding: utf-8 -*-
 
+std_trap = trap("INT") { exit! 130 } # no backtrace thanks
+
 HOMEBREW_BREW_FILE = ENV['HOMEBREW_BREW_FILE'] = File.expand_path(__FILE__)
 
 require 'pathname'
@@ -49,6 +51,8 @@ rescue LoadError => e
 end
 
 begin
+  trap("INT", std_trap) # restore default CTRL-C handler
+
   aliases = {'ls' => :list,
              'homepage' => :home,
              '-S' => :search,