[SourcesManager] Ignore repos with unreachable sources on update

lib/cocoapods/sources_manager.rb

@@ -145,7 +145,7 @@ module Pod
           raise Informative, "The `#{source_name}` repo is not a git repo." unless git_repo?(specified_source.repo)
           sources = [specified_source]
         else
-          sources = aggregate.all.select { |source| git_repo?(source.repo) }
+          sources = aggregate.all.select { |source| git_repo?(source.repo) && git_remote_reachable?(source.repo) }
         end
 
         sources.each do |source|
@@ -159,12 +159,24 @@ module Pod
         end
       end
 
+      # Returns whether a git repo's remote is reachable.
+      #
+      # @param  [Pathname] dir
+      #         The directory where the source is stored.
+      #
+      # @return [Bool] Whether the given source's remote is reachable.
+      #
+      def git_remote_reachable?(dir)
+        Dir.chdir(dir) { `git ls-remote` }
+        $?.exitstatus.zero?
+      end
+
       # Returns whether a source is a GIT repo.
       #
       # @param  [Pathname] dir
       #         The directory where the source is stored.
       #
-      # @return [Bool] Wether the given source is a GIT repo.
+      # @return [Bool] Whether the given source is a GIT repo.
       #
       def git_repo?(dir)
         Dir.chdir(dir) { `git rev-parse  >/dev/null 2>&1` }

spec/unit/sources_manager_spec.rb

@@ -95,6 +95,11 @@ module Pod
         UI.output.should.match /Already up-to-date/
       end
 
+      it 'returns whether a source has a reachable git remote' do
+        SourcesManager.git_remote_reachable?(repo_make('a_new_repo_that_is_new')).should.be.false
+        SourcesManager.git_remote_reachable?(SourcesManager.master_repo_dir).should.be.true
+      end
+
       it "returns whether a source is backed by a git repo" do
         SourcesManager.git_repo?(SourcesManager.master_repo_dir).should.be.true
         SourcesManager.git_repo?(Pathname.new('/tmp')).should.be.false