show error if Gemfile is not watched

Author: e2

lib/guard/bundler/templates/Guardfile

@@ -1,5 +1,11 @@
 guard :bundler do
-  watch('Gemfile')
-  # Uncomment next line if your Gemfile contains the `gemspec' command.
-  # watch(/^.+\.gemspec/)
+  require 'guard/bundler'
+  require 'guard/bundler/verify'
+  helper = Guard::Bundler::Verify.new
+
+  files = ['Gemfile']
+  files += Dir['*.gemspec'] if files.any? { |f| helper.uses_gemspec?(f) }
+
+  # Assume files are symlinked from somewhere
+  files.each { |file| watch(helper.real_path(file)) }
 end

lib/guard/bundler/verify.rb

@@ -0,0 +1,54 @@
+require 'pathname'
+
+module Guard
+  class Bundler < Plugin
+    class Verify
+      if Gem.win_platform?
+        SYMLINK_NEEDED = <<-EOS
+  Error: Guard will not detect changes to your Gemfile!
+
+  Solution: move the Gemfile to a watched directory and symlink it, so that
+  'Gemfile' is symlinked e.g. to config/Gemfile.
+
+  (See: https://github.com/guard/guard/wiki/Optimizing-for-large-projects)
+
+        EOS
+      else
+        SYMLINK_NEEDED = <<-EOS
+  Error: Guard will not detect changes to your Gemfile!
+
+  Solution: move the Gemfile to a watched directory and symlink it back.
+
+  Example:
+
+    $ mkdir config
+    $ git mv Gemfile config # use just 'mv' if this doesn't work
+    $ ln -s config/Gemfile .
+
+  and add config to the `directories` statement in your Guardfile.
+
+  (See: https://github.com/guard/guard/wiki/Optimizing-for-large-projects)
+        EOS
+      end
+
+      def verify!(file)
+        watchdirs = Guard::Compat.watched_directories
+
+        gemfile = Pathname.new(file)
+        config_dir = gemfile.realpath.dirname
+        return if watchdirs.include?(config_dir)
+
+        Compat::UI.error SYMLINK_NEEDED
+      end
+
+      def real_path(file)
+        verify!(file)
+        Pathname.new(file).realpath.relative_path_from(Pathname.pwd).to_s
+      end
+
+      def uses_gemspec?(file)
+        IO.read(file).lines.map(&:strip).grep(/^gemspec$/).any?
+      end
+    end
+  end
+end

spec/guard/bundler/template_spec.rb

@@ -0,0 +1,74 @@
+require "guard/compat/test/template"
+
+require "guard/bundler"
+
+# This is included by the template
+require "guard/bundler/verify"
+
+module Guard
+  RSpec.describe Bundler do
+    describe "template" do
+      subject { Compat::Test::Template.new(described_class) }
+
+      let(:helper) { instance_double(Bundler::Verify) }
+
+      before do
+        allow(Bundler::Verify).to receive(:new).and_return(helper)
+        allow(helper).to receive(:uses_gemspec?).and_return(true)
+
+        allow(helper).to receive(:real_path).with('Gemfile').
+          and_return('Gemfile')
+
+        allow(Dir).to receive(:[]).and_return(%w(guard-foo.gemspec))
+
+        allow(helper).to receive(:real_path).with('guard-foo.gemspec').
+          and_return('guard-foo.gemspec')
+      end
+
+      context "when gemspec is used" do
+        before do
+          allow(helper).to receive(:uses_gemspec?).with('Gemfile').
+            and_return(true)
+        end
+
+        it "watches the gemspec" do
+          expect(subject.changed('config/guard-foo.gemspec')).
+            to eq(%w(config/guard-foo.gemspec))
+        end
+      end
+
+      context "when gemspec is not used" do
+        before do
+          allow(helper).to receive(:uses_gemspec?).with('Gemfile').
+            and_return(false)
+        end
+
+        it "does not watch the gemspec" do
+          expect(subject.changed('guard-foo.gemspec')).to eq(%w())
+        end
+      end
+
+      context "when Gemfile is not a symlink" do
+        before do
+          expect(helper).to receive(:real_path).with('Gemfile').
+            and_return('Gemfile')
+        end
+
+        it "watches Gemfile" do
+          expect(subject.changed('Gemfile')).to eq(%w(Gemfile))
+        end
+      end
+
+      context "with a symlinked Gemfile" do
+        before do
+          expect(helper).to receive(:real_path).with('Gemfile').
+            and_return('config/Gemfile')
+        end
+
+        it "watches the real Gemfile" do
+          expect(subject.changed('config/Gemfile')).to eq(%w(config/Gemfile))
+        end
+      end
+    end
+  end
+end

spec/guard/bundler/verify_spec.rb

@@ -0,0 +1,78 @@
+require "guard/bundler/verify"
+
+RSpec.describe Guard::Bundler::Verify do
+  describe '#uses_gemspec?' do
+    context "when gemspec is used" do
+      before do
+        allow(IO).to receive(:read).with('foo').and_return("\n\n  gemspec  \n")
+      end
+
+      it "detects used gemspec" do
+        expect(subject.uses_gemspec?('foo')).to be_truthy
+      end
+    end
+
+    context "when gemspec is not used" do
+      before do
+        allow(IO).to receive(:read).with('foo').and_return("gem 'rspec'\n")
+      end
+
+      it "does not detects gemspec usage" do
+        expect(subject.uses_gemspec?('foo')).to be_falsey
+      end
+    end
+  end
+
+  describe '#real_path' do
+    context "when Gemfile is not watched" do
+      before do
+        allow(Guard::Compat).to receive(:watched_directories).and_return(['/foo'])
+      end
+
+      it 'shows error' do
+        expect(Guard::Compat::UI).to receive(:error).
+          with(/Guard will not detect changes/)
+        subject.real_path('Gemfile')
+      end
+    end
+
+    context "when Gemfile is watched along with whole project" do
+      before do
+        allow(Guard::Compat).to receive(:watched_directories).
+          and_return([Pathname.pwd])
+      end
+
+      it 'shows no error' do
+        expect(Guard::Compat::UI).to_not receive(:error)
+        subject.real_path('Gemfile')
+      end
+
+      it 'returns relative path to file' do
+        expect(subject.real_path('Gemfile')).to eq('Gemfile')
+      end
+    end
+
+    context "when subdir is watched" do
+      before do
+        allow(Guard::Compat).to receive(:watched_directories).
+          and_return([Pathname.pwd + 'foo'])
+      end
+
+      context "when Gemfile is symlinked" do
+        before do
+          allow_any_instance_of(Pathname).to receive(:realpath).
+            and_return(Pathname.pwd + 'foo/Gemfile')
+        end
+
+        it "returns the relative real path" do
+          expect(subject.real_path('Gemfile')).to eq('foo/Gemfile')
+        end
+
+        it 'shows no error' do
+          expect(Guard::Compat::UI).to_not receive(:error)
+          subject.real_path('Gemfile')
+        end
+      end
+    end
+  end
+end