Add bundler before/after eval hooks for plugins

bundler/lib/bundler/definition.rb

@@ -34,7 +34,10 @@ def self.build(gemfile, lockfile, unlock)
 
       raise GemfileNotFound, "#{gemfile} not found" unless gemfile.file?
 
-      Dsl.evaluate(gemfile, lockfile, unlock)
+      Plugin.hook(Plugin::Events::GEM_BEFORE_EVAL, gemfile, lockfile, unlock)
+      Dsl.evaluate(gemfile, lockfile, unlock).tap do |definition|
+        Plugin.hook(Plugin::Events::GEM_AFTER_EVAL, definition)
+      end
     end
 
     #

bundler/lib/bundler/plugin/events.rb

@@ -56,6 +56,18 @@ def self.defined_event?(event)
       #   Includes an Array of Bundler::Dependency objects
       #   GEM_AFTER_INSTALL_ALL = "after-install-all"
       define :GEM_AFTER_INSTALL_ALL,  "after-install-all"
+
+      # @!parse
+      #   A hook called before the Gemfile is evaluated
+      #   Includes the Gemfile name, the Lockfile name, and the unlock options
+      #   GEM_BEFORE_EVAL = "before-eval"
+      define :GEM_BEFORE_EVAL, "before-eval"
+
+      # @!parse
+      #   A hook called after the Gemfile is evaluated
+      #   Includes a Bundler::Definition
+      #   GEM_AFTER_EVAL = "after-eval"
+      define :GEM_AFTER_EVAL, "after-eval"
     end
   end
 end

bundler/spec/plugins/hook_spec.rb

@@ -106,4 +106,55 @@
       expect(out).to include "installed gem rack : installed"
     end
   end
+
+  context "before-eval hook" do
+    before do
+      build_repo2 do
+        build_plugin "before-eval-plugin" do |s|
+          s.write "plugins.rb", <<-RUBY
+            Bundler::Plugin::API.hook Bundler::Plugin::Events::GEM_BEFORE_EVAL do |gemfile, lockfile|
+              puts "hooked eval start of \#{File.basename(gemfile)} to \#{File.basename(lockfile)}"
+            end
+          RUBY
+        end
+      end
+
+      bundle "plugin install before-eval-plugin --source #{file_uri_for(gem_repo2)}"
+    end
+
+    it "runs before all rubygems are installed" do
+      install_gemfile <<-G
+        source "#{file_uri_for(gem_repo1)}"
+        gem "rake"
+      G
+
+      expect(out).to include "hooked eval start of Gemfile to Gemfile.lock"
+    end
+  end
+
+  context "after-eval hook" do
+    before do
+      build_repo2 do
+        build_plugin "after-eval-plugin" do |s|
+          s.write "plugins.rb", <<-RUBY
+            Bundler::Plugin::API.hook Bundler::Plugin::Events::GEM_AFTER_EVAL do |defn|
+              puts "hooked eval after with gems \#{defn.dependencies.map(&:name).join(", ")}"
+            end
+          RUBY
+        end
+      end
+
+      bundle "plugin install after-eval-plugin --source #{file_uri_for(gem_repo2)}"
+    end
+
+    it "runs before all rubygems are installed" do
+      install_gemfile <<-G
+        source "#{file_uri_for(gem_repo1)}"
+        gem "rack"
+        gem "rake"
+      G
+
+      expect(out).to include "hooked eval after with gems rack, rake"
+    end
+  end
 end