More defensive checks to see if lock file exists

lib/vendor/cli.rb

@@ -26,7 +26,7 @@ def update(lib_name=nil)
     def list
       manager = Vendor::Manager.new(Dir.pwd)
       say "Dependencies:\n"
-      manager.locked_libraries.each do |lib|
+      manager.libraries.each do |lib|
         say "  #{lib}", :yellow
       end
     end

lib/vendor/lock_file.rb

@@ -11,6 +11,12 @@ def initialize(lock_path, depfile, options={})
       @depfile = depfile
     end
 
+    # Returns if the file exists
+    # @lockfile.exists? => true
+    def exists?
+      File.exist?(@path)
+    end
+
     # Returns libraries specified in Vendor.lock
     # @lockfile.libraries => [<Library>, <Library>]
     def libraries

lib/vendor/manager.rb

@@ -37,6 +37,12 @@ def update!(library_name=nil)
       end
     end
 
+    # Returns the most accurate library list possible
+    # @manager.libraries => [<Library>, ...]
+    def libraries
+      self.locked_libraries || self.required_libraries
+    end
+
     # Returns the libraries required by Vendors file
     # @manager.required_libraries => [<Library>, ...]
     def required_libraries
@@ -46,12 +52,13 @@ def required_libraries
     # Returns libraries that are locked as dependencies in Vendors.lock
     # @manager.locked_libraries => [<Library>, ...]
     def locked_libraries
-      @lockfile.libraries
+      @lockfile.libraries if @lockfile.exists?
     end
 
     # Returns libraries that are missing from local installation
     # @manager.locked_libraries => [<Library>, ...]
     def missing_libraries
+      return self.required_libraries unless @lockfile.exists?
       self.locked_libraries.select do |lib|
         local_path = File.join(@vendored_path, lib.name)
         installed = @depfile.libraries.find { |l| l.name == lib.name }