Raise an Informative exception if a problem is (most likely) related to user…

Raise an Informative exception if a problem is (most likely) related to user error and make Command::Help a subclass of Informative.

lib/cocoa_pods.rb

 module Pod
+  class Informative < StandardError
+  end
+
   autoload :Command,       'cocoa_pods/command'
   autoload :Config,        'cocoa_pods/config'
   autoload :Dependency,    'cocoa_pods/dependency'

lib/cocoa_pods/command.rb

@@ -5,7 +5,7 @@ module Pod
     autoload :Setup,   'cocoa_pods/command/setup'
     autoload :Spec,    'cocoa_pods/command/spec'
 
-    class Help < Exception
+    class Help < Informative
       def initialize(command_class, argv)
         @command_class, @argv = command_class, argv
       end
@@ -46,7 +46,7 @@ module Pod
     def self.run(*argv)
       parse(*argv).run
     rescue Exception => e
-      unless e.is_a?(Help)
+      unless e.is_a?(Informative)
         puts "Oh no, an error occurred. Please run with `--verbose' and report " \
              "on https://github.com/alloy/cocoa-pods/issues."
         puts ""

lib/cocoa_pods/command/install.rb

@@ -32,13 +32,13 @@ module Pod
           if @podspec.exist?
             spec = Specification.from_podspec(@podspec)
           else
-            raise "The specified podspec `#{@podspec}' doesn't exist."
+            raise Help, "The specified podspec `#{@podspec}' doesn't exist."
           end
         else
           if config.project_podfile.exist?
             spec = Specification.from_podfile(config.project_podfile)
           else
-            raise "No Podfile found in current working directory."
+            raise Help, "No Podfile found in current working directory."
           end
         end
         Installer.new(spec, config.project_pods_root).install!

lib/cocoa_pods/command/repo.rb

@@ -30,7 +30,7 @@ module Pod
         case @action = argv.arguments[0]
         when 'add'
           unless (@name = argv[1]) && (@url = argv[2])
-            raise ArgumentError, "needs a NAME and URL"
+            raise Help, "Adding a repo needs a `name' and a `url'."
           end
         when 'update'
           @name = argv[1]

lib/cocoa_pods/source.rb

 module Pod
   class Source
     def self.all
-      @sources ||= Config.instance.repos_dir.children.select(&:directory?).map { |repo| new(repo) }
+      @sources ||= begin
+        repos_dir = Config.instance.repos_dir
+        sources = repos_dir.children.select(&:directory?).map { |repo| new(repo) }
+        if sources.empty?
+          raise Informative, "No spec repos found in `#{repos_dir}'. " \
+                             "To fetch the `master' repo run: $ pod setup"
+        end
+        sources
+      end
     end
 
     def self.search(dependency)
       all.map { |source| source.search(dependency) }.compact.first ||
-        raise("Unable to find a pod named `#{dependency.name}'")
+        raise(Informative, "Unable to find a pod named `#{dependency.name}'")
     end
 
     attr_reader :repo

lib/cocoa_pods/specification/set.rb

@@ -28,7 +28,7 @@ module Pod
         dependency = specification.dependency_by_name(name)
         unless @required_by.empty? || dependency.requirement.satisfied_by?(required_version)
           # TODO add graph that shows which dependencies led to this.
-          raise "#{specification} tries to activate `#{dependency}', " \
+          raise Informative, "#{specification} tries to activate `#{dependency}', " \
                              "but already activated version `#{required_version}' " \
                              "by #{@required_by.join(', ')}."
         end
@@ -59,10 +59,8 @@ module Pod
 
       # Return the first version that matches the current dependency.
       def required_version
-        unless v = versions.find { |v| dependency.match?(name, v) }
-          raise "Required version (#{dependency}) not found for `#{name}'."
-        end
-        v
+        versions.find { |v| dependency.match?(name, v) } ||
+          raise(Informative, "Required version (#{dependency}) not found for `#{name}'.")
       end
 
       def ==(other)

spec/unit/source_spec.rb

@@ -23,6 +23,6 @@ describe "Pod::Source" do
   it "raises if a specification set can't be found" do
     lambda {
       Pod::Source.search(Pod::Dependency.new('DoesNotExist'))
-    }.should.raise
+    }.should.raise Pod::Informative
   end
 end

spec/unit/specification/set_spec.rb

@@ -38,12 +38,14 @@ describe "Pod::Specification::Set" do
     @set.required_by(Pod::Spec.new { dependency 'ASIHTTPRequest', '> 1.7.9' })
     @set.required_by(Pod::Spec.new { dependency 'ASIHTTPRequest', '~> 1.8.0' })
     @set.required_by(Pod::Spec.new { dependency 'ASIHTTPRequest' })
-    lambda { @set.required_by(Pod::Spec.new { dependency 'ASIHTTPRequest', '< 1.8' }) }.should.raise
+    lambda {
+      @set.required_by(Pod::Spec.new { dependency 'ASIHTTPRequest', '< 1.8' })
+    }.should.raise Pod::Informative
   end
 
   it "raises if the required version doesn't exist" do
     @set.required_by(Pod::Spec.new { dependency 'ASIHTTPRequest', '< 1.8' })
-    lambda { @set.required_version }.should.raise
+    lambda { @set.required_version }.should.raise Pod::Informative
   end
 
   before do