bundle config --local gemfile /foo/bar/MyGemfile now works

lib/bundler.rb

@@ -193,7 +193,13 @@ def cache
     end
 
     def root
-      @root ||= default_gemfile.dirname.expand_path
+      @root ||= begin
+                  default_gemfile.dirname.expand_path
+                rescue GemfileNotFound
+                  bundle_dir = default_bundle_dir
+                  raise GemfileNotFound, "Could not locate Gemfile or .bundle/ directory" unless bundle_dir
+                  Pathname.new(File.expand_path("..", bundle_dir))
+                end
     end
 
     def app_config_path
@@ -221,7 +227,7 @@ def settings
       return @settings if defined?(@settings)
       @settings = Settings.new(app_config_path)
     rescue GemfileNotFound
-      @settings = Settings.new
+      @settings = Settings.new(Pathname.new(".bundle").expand_path)
     end
 
     def with_original_env
@@ -260,6 +266,10 @@ def default_lockfile
       SharedHelpers.default_lockfile
     end
 
+    def default_bundle_dir
+      SharedHelpers.default_bundle_dir
+    end
+
     def system_bindir
       # Gem.bindir doesn't always return the location that Rubygems will install
       # system binaries. If you put '-n foo' in your .gemrc, Rubygems will

lib/bundler/cli.rb

@@ -18,7 +18,8 @@ def self.start(*)
     def initialize(*args)
       super
       current_cmd = args.last[:current_command].name
-      ENV['BUNDLE_GEMFILE']   = File.expand_path(options[:gemfile]) if options[:gemfile]
+      custom_gemfile = options[:gemfile] || Bundler.settings[:gemfile]
+      ENV['BUNDLE_GEMFILE']   = File.expand_path(custom_gemfile) if custom_gemfile
       Bundler::Retry.attempts = options[:retry] || Bundler.settings[:retry] || Bundler::Retry::DEFAULT_ATTEMPTS
       Bundler.rubygems.ui = UI::RGProxy.new(Bundler.ui)
       auto_install if AUTO_INSTALL_CMDS.include?(current_cmd)

lib/bundler/shared_helpers.rb

@@ -36,6 +36,11 @@ def default_lockfile
       end
     end
 
+    def default_bundle_dir
+      bundle_dir = find_directory(".bundle")
+      Pathname.new(bundle_dir) if bundle_dir
+    end
+
     def in_bundle?
       find_gemfile
     end
@@ -75,6 +80,22 @@ def find_gemfile
       given = ENV['BUNDLE_GEMFILE']
       return given if given && !given.empty?
 
+      find_file('Gemfile', 'gems.rb')
+    end
+
+    def find_file(*names)
+      search_up(*names) {|filename|
+        return filename if File.file?(filename)
+      }
+    end
+
+    def find_directory(*names)
+      search_up(*names) {|dirname|
+        return dirname if File.directory?(dirname)
+      }
+    end
+
+    def search_up(*names)
       previous = nil
       current  = File.expand_path(SharedHelpers.pwd)
 
@@ -84,12 +105,10 @@ def find_gemfile
           return nil if File.file?(File.join(current, 'bundler.gemspec'))
         end
 
-        # otherwise return the Gemfile if it's there
-        ['Gemfile', 'gems.rb'].each do |file|
-          path = File.join(current, file)
-          return path if File.file?(path)
+        names.each do |name|
+          filename = File.join(current, name)
+          yield filename
         end
-
         current, previous = File.expand_path("..", current), current
       end
     end

man/bundle-config.ronn

@@ -90,6 +90,12 @@ learn more about their operation in [bundle install(1)][bundle-install].
 * `bin` (`BUNDLE_BIN`):
   Install executables from gems in the bundle to the specified directory.
   Defaults to `false`.
+* `gemfile` (`BUNDLE_GEMFILE`):
+  The name of the file that bundler should use as the `Gemfile`. This location
+  of this file also sets the root of the project, which is used to resolve
+  relative paths in the `Gemfile`, among other things. By default, bundler
+  will search up from the current working directory until it finds a
+  `Gemfile`.
 * `ssl_ca_cert` (`BUNDLE_SSL_CA_CERT`):
   Path to a designated CA certificate file or folder containing multiple
   certificates for trusted CAs in PEM format.
@@ -104,18 +110,6 @@ You can set them globally either via environment variables or `bundle config`,
 whichever is preferable for your setup. If you use both, environment variables
 will take preference over global settings.
 
-An additional setting is available only as an environment variable:
-
-* `BUNDLE_GEMFILE`:
-  The name of the file that bundler should use as the `Gemfile`. This location
-  of this file also sets the root of the project, which is used to resolve
-  relative paths in the `Gemfile`, among other things. By default, bundler
-  will search up from the current working directory until it finds a
-  `Gemfile`.
-
-Bundler will ignore any `BUNDLE_GEMFILE` entries in local or global
-configuration files.
-
 ## LOCAL GIT REPOS
 
 Bundler also allows you to work against a git repository locally

spec/commands/config_spec.rb

@@ -244,5 +244,23 @@
       expect(out).to match(long_string)
     end
   end
+end
+
+describe "setting gemfile via config" do
+  context "when only the non-default Gemfile exists" do
+    before do
+      gemfile bundled_app("NotGemfile"), <<-G
+      source "file://#{gem_repo1}"
+      gem 'rack'
+      G
+    end
+    it "persists the gemfile location to .bundle/config" do
 
+      bundle "config --local gemfile #{bundled_app("NotGemfile")}"
+      expect(File.exists?(".bundle/config")).to eq(true)
+
+      bundle "config"
+      expect(out).to include("NotGemfile")
+    end
+  end
 end

spec/install/gemfile_spec.rb

@@ -26,6 +26,32 @@
     end
   end
 
+  context "with gemfile set via config" do
+    before do
+      gemfile bundled_app("NotGemfile"), <<-G
+        source "file://#{gem_repo1}"
+        gem 'rack'
+      G
+
+      bundle "config --local gemfile #{bundled_app("NotGemfile")}"
+    end
+    it "uses the gemfile to install" do
+      bundle "install"
+      bundle "show"
+
+      expect(out).to include("rack (1.0.0)")
+    end
+    it "uses the gemfile while in a subdirectory" do
+      bundled_app("subdir").mkpath
+      Dir.chdir(bundled_app("subdir")) do
+        bundle "install"
+        bundle "show"
+
+        expect(out).to include("rack (1.0.0)")
+      end
+    end
+  end
+
   context "with deprecated features" do
     before :each do
       in_app_root