Bundler 2 [pre-release]: Detect bundler version to use when bundler 2 is available

bundler/helpers/v2/run.rb

@@ -11,7 +11,7 @@
 
 require "functions"
 
-MIN_BUNDLER_VERSION = "2.0.0"
+MIN_BUNDLER_VERSION = "2.1.0"
 
 def validate_bundler_version!
   return true if correct_bundler_version?

bundler/lib/dependabot/bundler/helpers.rb

@@ -5,23 +5,37 @@ module Bundler
     module Helpers
       V1 = "1"
       V2 = "2"
+      # If we are updating a project with no Gemfile.lock, we default to the
+      # newest version we support
+      DEFAULT = V2
+      # If we are updating a project with a Gemfile.lock that does not specify
+      # the version it was bundled with, with failover to V1 on the assumption
+      # it was created with an old version that didn't add this information
+      FAILOVER = V1
 
-      # NOTE: options is a manditory argument to ensure we pass it from all calling classes
-      def self.bundler_version(_lockfile, options:)
-        # For now, force V2 if bundler_2_available
-        return V2 if options[:bundler_2_available]
+      BUNDLER_MAJOR_VERSION_REGEX = /BUNDLED WITH\s+(?<version>\d+)\./m.freeze
 
-        # TODO: Add support for bundler v2 based on lockfile
-        # return V2 if lockfile.content.match?(/BUNDLED WITH\s+2/m)
+      # NOTE: options is a manditory argument to ensure we pass it from all calling classes
+      def self.bundler_version(lockfile, options:)
+        # TODO: Remove once bundler 2 is fully supported
+        return V1 unless options[:bundler_2_available]
+        return DEFAULT unless lockfile
 
-        V1
+        if (matches = lockfile.content.match(BUNDLER_MAJOR_VERSION_REGEX))
+          matches[:version].to_i >= 2 ? V2 : V1
+        else
+          FAILOVER
+        end
       end
 
       def self.detected_bundler_version(lockfile)
         return "unknown" unless lockfile
-        return V2 if lockfile.content.match?(/BUNDLED WITH\s+2/m)
 
-        V1
+        if (matches = lockfile.content.match(BUNDLER_MAJOR_VERSION_REGEX))
+          matches[:version]
+        else
+          FAILOVER
+        end
       end
     end
   end

bundler/spec/dependabot/bundler/helper_spec.rb

@@ -0,0 +1,124 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+require "dependabot/bundler/helpers"
+
+RSpec.describe Dependabot::Bundler::Helpers do
+  let(:no_lockfile) { nil }
+
+  let(:lockfile_bundled_with_missing) do
+    Dependabot::DependencyFile.new(name: "Gemfile.lock", content: <<~LOCKFILE)
+      Mock Gemfile.lock Content Goes Here
+    LOCKFILE
+  end
+
+  let(:lockfile_bundled_with_v1) do
+    Dependabot::DependencyFile.new(name: "Gemfile.lock", content: <<~LOCKFILE)
+      Mock Gemfile.lock Content Goes Here
+
+      BUNDLED WITH
+        1.17.3
+    LOCKFILE
+  end
+
+  let(:lockfile_bundled_with_v2) do
+    Dependabot::DependencyFile.new(name: "Gemfile.lock", content: <<~LOCKFILE)
+      Mock Gemfile.lock Content Goes Here
+
+      BUNDLED WITH
+        2.2.11
+    LOCKFILE
+  end
+
+  let(:lockfile_bundled_with_future_version) do
+    Dependabot::DependencyFile.new(name: "Gemfile.lock", content: <<~LOCKFILE)
+      Mock Gemfile.lock Content Goes Here
+
+      BUNDLED WITH
+        3.9.99
+    LOCKFILE
+  end
+
+  describe "#bundler_version" do
+    def described_method(lockfile)
+      described_class.bundler_version(lockfile, options: options)
+    end
+
+    context "when bundler 2 is not available" do
+      let(:options) { {} }
+
+      it "is 1 if there is no lockfile" do
+        expect(described_method(no_lockfile)).to eql("1")
+      end
+
+      it "is 1 if there is no bundled with string" do
+        expect(described_method(lockfile_bundled_with_missing)).to eql("1")
+      end
+
+      it "is 1 if it was bundled with a v1.x version" do
+        expect(described_method(lockfile_bundled_with_v1)).to eql("1")
+      end
+
+      it "is 1 if it was bundled with a v2.x version" do
+        expect(described_method(lockfile_bundled_with_v2)).to eql("1")
+      end
+
+      it "is 1 if it was bundled with a future version" do
+        expect(described_method(lockfile_bundled_with_future_version)).to eql("1")
+      end
+    end
+
+    context "when bundler 2 is available" do
+      let(:options) do
+        { bundler_2_available: true }
+      end
+
+      it "is 2 if there is no lockfile" do
+        expect(described_method(no_lockfile)).to eql("2")
+      end
+
+      it "is 1 if there is no bundled with string" do
+        expect(described_method(lockfile_bundled_with_missing)).to eql("1")
+      end
+
+      it "is 1 if it was bundled with a v1.x version" do
+        expect(described_method(lockfile_bundled_with_v1)).to eql("1")
+      end
+
+      it "is 2 if it was bundled with a v2.x version" do
+        expect(described_method(lockfile_bundled_with_v2)).to eql("2")
+      end
+
+      it "is 2 if it was bundled with a future version" do
+        expect(described_method(lockfile_bundled_with_future_version)).to eql("2")
+      end
+    end
+  end
+
+  describe "#detected_bundler_version" do
+    def described_method(lockfile)
+      described_class.detected_bundler_version(lockfile)
+    end
+
+    it "is unknown if there is no lockfile" do
+      expect(described_method(no_lockfile)).to eql("unknown")
+    end
+
+    it "is 1 if there is no bundled with string" do
+      expect(described_method(lockfile_bundled_with_missing)).to eql("1")
+    end
+
+    it "is 1 if it was bundled with a v1.x version" do
+      expect(described_method(lockfile_bundled_with_v1)).to eql("1")
+    end
+
+    it "is 2 if it was bundled with a v2.x version" do
+      expect(described_method(lockfile_bundled_with_v2)).to eql("2")
+    end
+
+    it "is 1 if it was bundled with a future version" do
+      expect(described_method(lockfile_bundled_with_future_version)).to eql("3")
+    end
+  end
+end