Remove stale gem RBIs on generate (#616)

Author: vinistock

lib/tapioca/generators/gem.rb

@@ -51,18 +51,27 @@ def initialize(
       def generate
         require_gem_file
 
-        gems_to_generate(@gem_names)
-          .reject { |gem| @gem_excludes.include?(gem.name) }
-          .each do |gem|
-            say("Processing '#{gem.name}' gem:", :green)
-            shell.indent do
-              compile_gem_rbi(gem)
-              puts
-            end
+        gems_to_process = gems_to_generate(@gem_names).reject { |gem| @gem_excludes.include?(gem.name) }
+
+        anything_done = [
+          perform_removals,
+          gems_to_process.any?,
+        ].any?
+
+        gems_to_process.each do |gem|
+          say("Processing '#{gem.name}' gem:", :green)
+          shell.indent do
+            compile_gem_rbi(gem)
+            puts
           end
+        end
 
-        say("All operations performed in working directory.", [:green, :bold])
-        say("Please review changes and commit them.", [:green, :bold])
+        if anything_done
+          say("All operations performed in working directory.", [:green, :bold])
+          say("Please review changes and commit them.", [:green, :bold])
+        else
+          say("No operations performed, all RBIs are up-to-date.", [:green, :bold])
+        end
       end
 
       sig { params(should_verify: T::Boolean).void }

spec/tapioca/cli/gem_spec.rb

@@ -185,6 +185,22 @@ def fizz; end
           refute_path_exists("#{repo_path}/sorbet/rbi/gems/baz@0.0.2.rbi")
         end
 
+        it "must remove outdated RBIs" do
+          FileUtils.touch("#{outdir}/outdated@5.0.0.rbi")
+
+          output = tapioca("gem foo")
+
+          assert_includes(output, <<~OUTPUT)
+            Processing 'foo' gem:
+              Compiling foo, this may take a few seconds...   Done
+          OUTPUT
+
+          assert_includes(output, "-- Removing: #{outdir}/outdated@5.0.0.rbi\n")
+
+          assert_path_exists("#{outdir}/foo@0.0.1.rbi")
+          refute_path_exists("#{outdir}/outdated@5.0.0.rbi")
+        end
+
         it "must perform postrequire properly" do
           output = tapioca("gem foo --postrequire #{repo_path / "postrequire.rb"}")