Keep same error interface

Only suppress backtrace from likely errors

bin/compile

@@ -23,7 +23,7 @@ rescue Exception => e
     Kernel.puts " !     #{line.strip}"
   end
   Kernel.puts " !"
-  if e.is_a?(LanguagePack::BuildpackError)
+  if e.is_a?(BuildpackError)
     exit 1
   else
     raise e

lib/language_pack/helpers/bundler_wrapper.rb

@@ -1,7 +1,7 @@
 class LanguagePack::Helpers::BundlerWrapper
   include LanguagePack::ShellHelpers
 
-  class GemfileParseError < LanguagePack::BuildpackError
+  class GemfileParseError < BuildpackError
     def initialize(error)
       msg = "There was an error parsing your Gemfile, we cannot continue\n"
       msg << error

lib/language_pack/helpers/rake_runner.rb

@@ -28,8 +28,8 @@ def status?
 
     # Is set by RakeTask#invoke to one of the ALLOWED verbs
     def status
-      raise LanguagePack::BuildpackError, "Status not set for #{self.inspect}" if @status == :nil
-      raise LanguagePack::BuildpackError, "Not allowed status: #{@status} for #{self.inspect}" unless ALLOWED.include?(@status)
+      raise "Status not set for #{self.inspect}" if @status == :nil
+      raise "Not allowed status: #{@status} for #{self.inspect}" unless ALLOWED.include?(@status)
       @status
     end
 

lib/language_pack/no_lockfile.rb

@@ -11,6 +11,6 @@ def name
   end
 
   def compile
-    raise LanguagePack::BuildpackError, "Gemfile.lock required. Please check it in."
+    error "Gemfile.lock required. Please check it in."
   end
 end

lib/language_pack/ruby.rb

@@ -143,7 +143,7 @@ def slug_vendor_base
         @slug_vendor_base = "vendor/bundle/1.8"
       else
         @slug_vendor_base = run_no_pipe(%q(ruby -e "require 'rbconfig';puts \"vendor/bundle/#{RUBY_ENGINE}/#{RbConfig::CONFIG['ruby_version']}\"")).chomp
-        raise LanguagePack::BuildpackError, "Problem detecting bundler vendor directory: #{@slug_vendor_base}" unless $?.success?
+        error "Problem detecting bundler vendor directory: #{@slug_vendor_base}" unless $?.success?
         @slug_vendor_base
       end
     end
@@ -264,7 +264,7 @@ def install_ruby
             expected_checksum = File.read(sha_file).chomp
             actual_checksum   = Digest::SHA1.file(file).hexdigest
 
-            raise LanguagePack::BuildpackError, <<-ERROR_MSG unless expected_checksum == actual_checksum
+            error <<-ERROR_MSG unless expected_checksum == actual_checksum
 RBX Checksum for #{file} does not match.
 Expected #{expected_checksum} but got #{actual_checksum}.
 Please try pushing again in a few minutes.
@@ -309,8 +309,9 @@ def install_ruby
 An error occurred while installing Ruby #{ruby_version.version}
 For supported Ruby versions see https://devcenter.heroku.com/articles/ruby-support#supported-runtimes
 Note: Only the most recent version of Ruby 2.1 is supported on Cedar-14
+#{error.message}
 ERROR
-    raise LanguagePack::BuildpackError, message + error.message
+    error message
   end
 
   def new_app?
@@ -550,7 +551,7 @@ def build_bundler
 ERROR
           end
 
-          raise LanguagePack::BuildpackError, error_message
+          error error_message
         end
       end
     end
@@ -719,7 +720,7 @@ def precompile_fail(output)
       msg << "Attempted to access a nonexistent database:\n"
       msg << "https://devcenter.heroku.com/articles/pre-provision-database\n"
     end
-    raise LanguagePack::BuildpackError, msg
+    error msg
   end
 
   def bundler_cache

lib/language_pack/ruby_version.rb

@@ -2,7 +2,7 @@
 
 module LanguagePack
   class RubyVersion
-    class BadVersionError < LanguagePack::BuildpackError
+    class BadVersionError < BuildpackError
       def initialize(output = "")
         msg = ""
         msg << output

lib/language_pack/shell_helpers.rb

@@ -1,5 +1,9 @@
 require "shellwords"
 
+
+class BuildpackError < StandardError
+end
+
 class NoShellEscape < String
   def shellescape
     self
@@ -122,6 +126,10 @@ def warn(message, options = {})
       @warnings << message
     end
 
+    def error(message)
+      raise BuildpackError, message
+    end
+
     def deprecate(message)
       @deprecations ||= []
       @deprecations << message