1 files changed, 45 insertions, 0 deletions
diff --git a/lib/rubygems/core_ext/kernel_warn.rb b/lib/rubygems/core_ext/kernel_warn.rb
new file mode 100644
index 0000000000..f806b77fab
--- /dev/null
+++ b/lib/rubygems/core_ext/kernel_warn.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module Kernel
+  rubygems_path = "#{__dir__}/" # Frames to be skipped start with this path.
+
+  original_warn = instance_method(:warn)
+
+  remove_method :warn
+
+  class << self
+    remove_method :warn
+  end
+
+  module_function define_method(:warn) {|*messages, **kw|
+    unless uplevel = kw[:uplevel]
+      return original_warn.bind_call(self, *messages, **kw)
+    end
+
+    # Ensure `uplevel` fits a `long`
+    uplevel, = [uplevel].pack("l!").unpack("l!")
+
+    if uplevel >= 0
+      start = 0
+      while uplevel >= 0
+        loc, = caller_locations(start, 1)
+        unless loc
+          # No more backtrace
+          start += uplevel
+          break
+        end
+
+        start += 1
+
+        next unless path = loc.path
+        unless path.start_with?(rubygems_path, "<internal:")
+          # Non-rubygems frames
+          uplevel -= 1
+        end
+      end
+      kw[:uplevel] = start
+    end
+
+    original_warn.bind_call(self, *messages, **kw)
+  }
+end