[ruby/rubygems] Skip the newgem linter specs only when ast.rb is on RUBYLIB

An in-tree build of ruby core puts the source root on RUBYLIB, and its ast.rb shadows the ast gem that rubocop-ast requires. Out-of-source builds, as on CI, can run them.

https://github.com/ruby/rubygems/commit/9b08921212

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

spec/bundler/commands/newgem_spec.rb

@@ -38,6 +38,10 @@ RSpec.describe "bundle gem" do
     false
   end
 
+  def ast_rb_on_rubylib?
+    rubylib.any? {|dir| File.exist?(File.join(dir, "ast.rb")) }
+  end
+
   let(:generated_gemspec) { Bundler.load_gemspec_uncached(bundled_app(gem_name).join("#{gem_name}.gemspec")) }
 
   let(:gem_name) { "mygem" }
@@ -95,49 +99,49 @@ RSpec.describe "bundle gem" do
   end
 
   it "has no rubocop offenses when using --linter=rubocop flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
     bundle "gem #{gem_name} --linter=rubocop"
     bundle_exec_rubocop
     expect(last_command).to be_success
   end
 
   it "has no rubocop offenses when using --ext=c and --linter=rubocop flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
     bundle "gem #{gem_name} --ext=c --linter=rubocop"
     bundle_exec_rubocop
     expect(last_command).to be_success
   end
 
   it "has no rubocop offenses when using --ext=c, --test=minitest, and --linter=rubocop flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
     bundle "gem #{gem_name} --ext=c --test=minitest --linter=rubocop"
     bundle_exec_rubocop
     expect(last_command).to be_success
   end
 
   it "has no rubocop offenses when using --ext=c, --test=rspec, and --linter=rubocop flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
     bundle "gem #{gem_name} --ext=c --test=rspec --linter=rubocop"
     bundle_exec_rubocop
     expect(last_command).to be_success
   end
 
   it "has no rubocop offenses when using --ext=c, --test=test-unit, and --linter=rubocop flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
     bundle "gem #{gem_name} --ext=c --test=test-unit --linter=rubocop"
     bundle_exec_rubocop
     expect(last_command).to be_success
   end
 
   it "has no standard offenses when using --linter=standard flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
     bundle "gem #{gem_name} --linter=standard"
     bundle_exec_standardrb
     expect(last_command).to be_success
   end
 
   it "has no rubocop offenses when using --ext=rust and --linter=rubocop flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
 
     bundle "gem #{gem_name} --ext=rust --linter=rubocop"
     bundle_exec_rubocop
@@ -145,7 +149,7 @@ RSpec.describe "bundle gem" do
   end
 
   it "has no rubocop offenses when using --ext=rust, --test=minitest, and --linter=rubocop flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
 
     bundle "gem #{gem_name} --ext=rust --test=minitest --linter=rubocop"
     bundle_exec_rubocop
@@ -153,7 +157,7 @@ RSpec.describe "bundle gem" do
   end
 
   it "has no rubocop offenses when using --ext=rust, --test=rspec, and --linter=rubocop flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
 
     bundle "gem #{gem_name} --ext=rust --test=rspec --linter=rubocop"
     bundle_exec_rubocop
@@ -161,7 +165,7 @@ RSpec.describe "bundle gem" do
   end
 
   it "has no rubocop offenses when using --ext=rust, --test=test-unit, and --linter=rubocop flag" do
-    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    skip "an in-tree ruby/ruby build puts its ast.rb on RUBYLIB, shadowing the ast gem" if ast_rb_on_rubylib?
 
     bundle "gem #{gem_name} --ext=rust --test=test-unit --linter=rubocop"
     bundle_exec_rubocop