Merge pull request #12901 from Earlopain/bundler-gemfile-error

[Fix #12876] Fix lockfile parsing if only the gemfile exists

changelog/fix_lockfile_parser_without_lockfile.md

@@ -0,0 +1 @@
+* [#12876](https://github.com/rubocop/rubocop/issues/12876): Fix an error for the lockfile parser if a gemfile exists but a lockfile doesn't. ([@earlopain][])

lib/rubocop/lockfile.rb

@@ -72,7 +72,7 @@ def includes_gem?(name)
     def parser
       return @parser if defined?(@parser)
 
-      @parser = if @lockfile_path && bundler_lock_parser_defined?
+      @parser = if @lockfile_path && File.exist?(@lockfile_path) && bundler_lock_parser_defined?
                   begin
                     lockfile = ::Bundler.read_file(@lockfile_path)
                     ::Bundler::LockfileParser.new(lockfile) if lockfile

spec/rubocop/lockfile_spec.rb

@@ -53,6 +53,19 @@
 
       it { is_expected.to eq([]) }
     end
+
+    context 'when there is a gemfile without lockfile' do
+      let(:lockfile) { nil }
+
+      before do
+        allow(Bundler).to receive(:default_lockfile).and_return('Gemfile.lock')
+        create_file('Gemfile', <<~GEMFILE)
+          gem 'rubocop', '~> 1.65.0'
+        GEMFILE
+      end
+
+      it { is_expected.to eq([]) }
+    end
   end
 
   describe '#dependencies' do