Merge pull request #5942 from MikeMcQuaid/system-not-exec

*cmd/*: use *system instead of exec for easier testing.

Library/Homebrew/cmd/cat.rb

@@ -23,6 +23,6 @@ module Homebrew
     raise "`brew cat` doesn't support multiple arguments" if args.remaining.size > 1
 
     cd HOMEBREW_REPOSITORY
-    exec "cat", formulae.first.path, *ARGV.options_only
+    safe_system "cat", formulae.first.path, *ARGV.options_only
   end
 end

Library/Homebrew/cmd/list.rb

@@ -46,8 +46,7 @@ module Homebrew
   def list
     list_args.parse
 
-    # Use of exec means we don't explicitly exit
-    list_unbrewed if args.unbrewed?
+    return list_unbrewed if args.unbrewed?
 
     # Unbrewed uses the PREFIX, which will exist
     # Things below use the CELLAR, which doesn't until the first formula is installed.
@@ -67,10 +66,10 @@ module Homebrew
         puts Formatter.columns(full_names)
       else
         ENV["CLICOLOR"] = nil
-        exec "ls", *ARGV.options_only << HOMEBREW_CELLAR
+        safe_system "ls", *ARGV.options_only << HOMEBREW_CELLAR
       end
     elsif args.verbose? || !$stdout.tty?
-      exec "find", *ARGV.kegs.map(&:to_s) + %w[-not -type d -print]
+      safe_system "find", *ARGV.kegs.map(&:to_s) + %w[-not -type d -print]
     else
       ARGV.kegs.each { |keg| PrettyListing.new keg }
     end
@@ -116,7 +115,7 @@ module Homebrew
     arguments.concat %w[)]
 
     cd HOMEBREW_PREFIX
-    exec "find", *arguments
+    safe_system "find", *arguments
   end
 
   def filtered_list

Library/Homebrew/cmd/log.rb

@@ -56,6 +56,6 @@ module Homebrew
     end
     args = ARGV.options_only
     args += ["--follow", "--", path] unless path.nil?
-    exec "git", "log", *args
+    system "git", "log", *args
   end
 end

Library/Homebrew/cmd/sh.rb

@@ -51,6 +51,6 @@ module Homebrew
       When done, type `exit'.
     EOS
     $stdout.flush
-    exec ENV["SHELL"]
+    safe_system ENV["SHELL"]
   end
 end

Library/Homebrew/dev-cmd/prof.rb

@@ -19,6 +19,6 @@ module Homebrew
     Homebrew.install_gem_setup_path! "ruby-prof"
     FileUtils.mkdir_p "prof"
     brew_rb = (HOMEBREW_LIBRARY_PATH/"brew.rb").resolved_path
-    exec "ruby-prof", "--printer=multi", "--file=prof", brew_rb, "--", *ARGV
+    safe_system "ruby-prof", "--printer=multi", "--file=prof", brew_rb, "--", *ARGV
   end
 end

Library/Homebrew/dev-cmd/ruby.rb

@@ -21,6 +21,9 @@ module Homebrew
   def ruby
     ruby_args.parse
 
-    exec ENV["HOMEBREW_RUBY_PATH"], "-I", $LOAD_PATH.join(File::PATH_SEPARATOR), "-rglobal", "-rdev-cmd/irb", *ARGV
+    safe_system ENV["HOMEBREW_RUBY_PATH"],
+                "-I", $LOAD_PATH.join(File::PATH_SEPARATOR),
+                "-rglobal", "-rdev-cmd/irb",
+                *ARGV
   end
 end

Library/Homebrew/utils.rb

@@ -321,7 +321,7 @@ end
 
 def exec_editor(*args)
   puts "Editing #{args.join "\n"}"
-  with_homebrew_path { safe_exec(which_editor, *args) }
+  with_homebrew_path { safe_system(which_editor, *args) }
 end
 
 def exec_browser(*args)
@@ -331,13 +331,7 @@ def exec_browser(*args)
 
   ENV["DISPLAY"] = ENV["HOMEBREW_DISPLAY"]
 
-  safe_exec(browser, *args)
-end
-
-def safe_exec(cmd, *args)
-  # This buys us proper argument quoting and evaluation
-  # of environment variables in the cmd parameter.
-  exec "/bin/sh", "-c", "#{cmd} \"$@\"", "--", *args
+  safe_system(browser, *args)
 end
 
 # GZips the given paths, and returns the gzipped paths