Use bundle-locked gem versions in child contexts

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    spoom (1.7.9)
+    spoom (1.7.10)
       erubi (>= 1.10.0)
       prism (>= 0.28.0)
       rbi (>= 0.3.3)

lib/spoom/bundler_helper.rb

@@ -0,0 +1,33 @@
+# typed: strict
+# frozen_string_literal: true
+
+module Spoom
+  module BundlerHelper
+    extend T::Sig
+
+    class << self
+      # Generate a gem requirement for the given gem name, using that gem's version in the "real" current bundle.
+      #
+      # This ensures that any child Spoom::Contexts use predictable gem versions,
+      # without having to manually specify them and bump them to stay in sync with Spoom's real Gemfile.
+      #
+      # Given `"foo"`, returns a string like 'gem "foo", "= 1.2.3"', suitable for inserting into a Gemfile.
+      #: (String) -> String
+      def gem_requirement_from_real_bundle(gem_name)
+        specs = Bundler.load.gems[gem_name]
+
+        if specs.nil? || specs.empty?
+          raise "Did not find gem #{gem_name.inspect} in the current bundle"
+        elsif specs.count > 1
+          raise <<~MSG
+            Found multiple versions of #{gem_name.inspect} in the current bundle:
+            #{specs.sort_by(&:version).map { |spec| "  - #{spec.name} #{spec.version}" }.join("\n")}
+          MSG
+        else
+          spec = specs.first
+          %(gem "#{spec.name}", "= #{spec.version}")
+        end
+      end
+    end
+  end
+end

lib/spoom/cli/srb/sigs.rb

@@ -1,6 +1,8 @@
 # typed: true
 # frozen_string_literal: true
 
+require "spoom/bundler_helper"
+
 module Spoom
   module Cli
     module Srb
@@ -142,13 +144,14 @@ class Module; include T::Sig; end
           # Now we create a new context to import our modified gem and run tapioca
           say("Running Tapioca...")
           tapioca_context = Spoom::Context.mktmp!
-          tapioca_context.write!("Gemfile", <<~RB)
+          tapioca_context.write_gemfile!(<<~GEMFILE)
             source "https://rubygems.org"
 
-            gem "rbs", ">= 4.0.0.dev.4"
-            gem "tapioca"
+            #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("rbs")}
+            #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("tapioca")}
+
             gem "#{spec.name}", path: "#{copy_context.absolute_path}"
-          RB
+          GEMFILE
           exec(tapioca_context, "bundle install")
           exec(tapioca_context, "bundle exec tapioca gem #{spec.name} --no-doc --no-loc --no-file-header")
 

lib/spoom/context/bundle.rb

@@ -48,7 +48,7 @@ def gemfile_lock_specs
         return {} unless file?("Gemfile.lock")
 
         parser = Bundler::LockfileParser.new(read_gemfile_lock)
-        parser.specs.map { |spec| [spec.name, spec] }.to_h
+        parser.specs.to_h { |spec| [spec.name, spec] }
       end
 
       # Get `gem` version from the `Gemfile.lock` content

lib/spoom/version.rb

@@ -2,5 +2,5 @@
 # frozen_string_literal: true
 
 module Spoom
-  VERSION = "1.7.9"
+  VERSION = "1.7.10"
 end

rbi/spoom.rbi

@@ -11,6 +11,13 @@ module Spoom
   end
 end
 
+module Spoom::BundlerHelper
+  class << self
+    sig { params(gem_name: ::String).returns(::String) }
+    def gem_requirement_from_real_bundle(gem_name); end
+  end
+end
+
 module Spoom::Cli; end
 
 class Spoom::Cli::Deadcode < ::Thor

test/spoom/bundler_helper_test.rb

@@ -0,0 +1,21 @@
+# typed: true
+# frozen_string_literal: true
+
+require "test_helper"
+
+module Spoom
+  class BundlerHelperTest < Minitest::Test
+    def test_gem_requirement_from_real_bundle_returns_gem_requirement_string
+      gem_from_spoom_bundle = "tapioca"
+      gem_requirement = BundlerHelper.gem_requirement_from_real_bundle(gem_from_spoom_bundle)
+
+      assert_match(/^gem "#{gem_from_spoom_bundle}", "= .+"$/, gem_requirement)
+    end
+
+    def test_raises_if_gem_not_found_in_bundle
+      assert_raises(RuntimeError) do
+        BundlerHelper.gem_requirement_from_real_bundle("not-real")
+      end
+    end
+  end
+end

test/spoom/context/sorbet_test.rb

@@ -34,7 +34,7 @@ def test_context_run_srb_from_bundle
         context.write_gemfile!(<<~GEMFILE)
           source "https://rubygems.org"
 
-          gem "sorbet"
+          #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("sorbet")}
         GEMFILE
         context.bundle("config set --local path $GEM_HOME")
         context.bundle_install!
@@ -67,7 +67,7 @@ def test_context_run_srb_from_path
         context.write_gemfile!(<<~GEMFILE)
           source "https://rubygems.org"
 
-          gem "sorbet"
+          #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("sorbet")}
         GEMFILE
         context.bundle_install!
 
@@ -163,7 +163,7 @@ def test_context_srb_version_return_version_string
         context.write_gemfile!(<<~GEMFILE)
           source "https://rubygems.org"
 
-          gem "sorbet"
+          #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("sorbet")}
         GEMFILE
         context.bundle_install!
 

test/spoom/deadcode/plugins_test.rb

@@ -51,8 +51,8 @@ def test_deadcode_plugins_with_sorbet
         plugins = plugins_classes_for_gemfile(<<~GEMFILE)
           source "https://rubygems.org"
 
-          gem "sorbet"
-          gem "sorbet-runtime"
+          #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("sorbet")}
+          #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("sorbet-runtime")}
         GEMFILE
 
         assert_equal(

test/test_helper.rb

@@ -22,21 +22,29 @@ def new_project(name = nil)
     # Default Gemfile contents requiring only Spoom
     #: -> String
     def spoom_gemfile
-      <<~GEMFILE
-        source("https://rubygems.org")
-
-        gemspec name: "spoom", path: "#{SPOOM_PATH}"
-        gem "tapioca"
-        gem "sorbet-static-and-runtime", "#{Sorbet::GEM_VERSION}"
-        gem "json", "2.7.2"
-      GEMFILE
+      Spoom::TestHelper.default_spoom_test_gemfile
     end
 
     # Replace all sorbet-like version "0.5.5888" in `test` by "X.X.XXXX"
     #: (String text) -> String
     def censor_sorbet_version(text)
       text.gsub(/\d\.\d\.\d{4,5}/, "X.X.XXXX")
     end
+
+    class << self
+      #: -> String
+      def default_spoom_test_gemfile
+        @default_spoom_test_gemfile ||= <<~GEMFILE #: String?
+          source("https://rubygems.org")
+
+          gemspec name: "spoom", path: "#{SPOOM_PATH}"
+
+          #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("tapioca")}
+          #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("sorbet-static-and-runtime")}
+          #{Spoom::BundlerHelper.gem_requirement_from_real_bundle("json")}
+        GEMFILE
+      end
+    end
   end
 end