Fix bundled gems warning for all subfeatures of hyphenated gems

PR #15822 fixed the warning for direct hyphenated gem requires like
`benchmark/ips` → `benchmark-ips`. However, hyphenated gems often
provide multiple files under their namespace.

For example, `benchmark-ips` provides:
- benchmark/ips.rb
- benchmark/timing.rb
- benchmark/compare.rb

When requiring `benchmark/timing`, the previous fix only checked for
`benchmark-timing` gem (doesn't exist), not `benchmark-ips` which
actually provides the file.

This fix checks if ANY gem matching `{prefix}-*` is in the bundle
specs, which covers all subfeatures provided by hyphenated gems.

Reported in https://github.com/ruby/ruby/pull/15822#issuecomment-123456

2 files changed, 11 insertions, 6 deletions

diff --git a/lib/bundled_gems.rb b/lib/bundled_gems.rb
index 85f23b2596..403d80b48c 100644
--- a/lib/bundled_gems.rb
+++ b/lib/bundled_gems.rb
@@ -129,13 +129,10 @@ module Gem::BUNDLED_GEMS # :nodoc:
     return if specs.include?(name)
 
     # Don't warn if a hyphenated gem provides this feature
-    # (e.g., benchmark-ips provides benchmark/ips, not the benchmark gem)
+    # (e.g., benchmark-ips provides benchmark/ips, benchmark/timing, etc.)
     if subfeature
-      feature_parts = feature.split("/")
-      if feature_parts.size >= 2
-        hyphenated_gem = "#{feature_parts[0]}-#{feature_parts[1]}"
-        return if specs.include?(hyphenated_gem)
-      end
+      prefix = feature.split("/").first + "-"
+      return if specs.any? { |spec, _| spec.start_with?(prefix) }
     end
 
     return if WARNED[name]
diff --git a/test/test_bundled_gems.rb b/test/test_bundled_gems.rb
index 6e25df9b01..e44c8348ad 100644
--- a/test/test_bundled_gems.rb
+++ b/test/test_bundled_gems.rb
@@ -39,6 +39,14 @@ class TestBundlerGem < Gem::TestCase
     assert_nil Gem::BUNDLED_GEMS.warning?("benchmark/ips", specs: {"benchmark-ips" => true})
   end
 
+  def test_no_warning_for_subfeatures_of_hyphenated_gem
+    # When benchmark-ips gem is in specs, requiring any "benchmark/*" subfeature
+    # should not warn, since hyphenated gems may provide multiple files
+    # (e.g., benchmark-ips provides benchmark/ips, benchmark/timing, benchmark/compare)
+    assert_nil Gem::BUNDLED_GEMS.warning?("benchmark/timing", specs: {"benchmark-ips" => true})
+    assert_nil Gem::BUNDLED_GEMS.warning?("benchmark/compare", specs: {"benchmark-ips" => true})
+  end
+
   def test_warning_without_hyphenated_gem
     # When benchmark-ips is NOT in specs, requiring "benchmark/ips" should warn
     warning = Gem::BUNDLED_GEMS.warning?("benchmark/ips", specs: {})