Only try mirrors for CurlDownloadStrategies

Also adjust output text slightly for prettiness.

A possibly useful side effect here is safe_system has a defined Exception (subclassing RuntimeError) now.

Library/Homebrew/download_strategy.rb

@@ -55,10 +55,14 @@ class CurlDownloadStrategy < AbstractDownloadStrategy
     unless @tarball_path.exist?
       begin
         _fetch
-      rescue Exception
+      rescue Exception => e
         ignore_interrupts { @tarball_path.unlink if @tarball_path.exist? }
+        if e.kind_of? ErrorDuringExecution
+          raise CurlDownloadStrategyError, "Download failed: #{@url}"
+        else
           raise
         end
+      end
     else
       puts "File already downloaded in #{File.dirname(@tarball_path)}"
     end

Library/Homebrew/exceptions.rb

@@ -113,16 +113,10 @@ class BuildError < Homebrew::InstallationError
   end
 end
 
-class DownloadError < RuntimeError
+# raised in CurlDownloadStrategy.fetch
-  attr :command
+class CurlDownloadStrategyError < RuntimeError
-  attr :args
+end
-  attr :exit_status
+
-
+# raised by safe_system in utils.rb
-  def initialize cmd, args, status
+class ErrorDuringExecution < RuntimeError
-    @command = cmd
-    @args = args
-    args.map!{ |arg| arg.to_s.gsub " ", "\\ " }
-    super "#{cmd} #{args.join ' '}\nDownloader failed with exit status #{status}"
-    @exit_status = status
-  end
 end

Library/Homebrew/formula.rb

@@ -561,9 +561,9 @@ private
 
     begin
       fetched = downloader.fetch
-    rescue DownloadError => e
+    rescue CurlDownloadStrategyError => e
       raise e if mirror_list.empty?
-      opoo "#{e.message}\nTrying a mirror."
+      puts "Trying a mirror..."
       url, specs = mirror_list.shift.values_at :url, :specs
       downloader = download_strategy.new url, name, version, specs
       retry

Library/Homebrew/utils.rb

@@ -92,7 +92,7 @@ end
 def safe_system cmd, *args
   unless Homebrew.system cmd, *args
     args = args.map{ |arg| arg.to_s.gsub " ", "\\ " } * " "
-    raise "Failure while executing: #{cmd} #{args}"
+    raise ErrorDuringExecution, "Failure while executing: #{cmd} #{args}"
   end
 end
 
@@ -106,13 +106,13 @@ end
 
 def curl *args
   curl = Pathname.new '/usr/bin/curl'
-  raise "#{curl} is not an executable!" unless curl.exist? and curl.executable?
+  raise "#{curl} is not executable" unless curl.exist? and curl.executable?
 
   args = [HOMEBREW_CURL_ARGS, HOMEBREW_USER_AGENT, *args]
   # See https://github.com/mxcl/homebrew/issues/6103
   args << "--insecure" if MacOS.version < 10.6
 
-  raise DownloadError.new curl, args, $? unless Homebrew.system curl, *args
+  safe_system curl, *args
 end
 
 def puts_columns items, star_items=[]