Merge branch 'sh-fix-infite-loop-peek-bar' into 'master'

Fix SystemStackError when Peek bar is active with Rugged calls

Closes #65404

See merge request gitlab-org/gitlab-ce!31357

lib/peek/views/rugged.rb

@@ -29,8 +29,12 @@ module Peek
 
       def format_args(args)
         args.map do |arg|
-          # Needed to avoid infinite as_json calls
-          if arg.is_a?(Gitlab::Git::Repository)
+          # ActiveSupport::JSON recursively calls as_json on all
+          # instance variables, and if that instance variable points to
+          # something that refers back to the same instance, we can wind
+          # up in an infinite loop. Currently this only seems to happen with
+          # Gitlab::Git::Repository and ::Repository.
+          if arg.instance_variables.present?
             arg.to_s
           else
             arg

spec/lib/peek/views/rugged_spec.rb

@@ -24,7 +24,7 @@ describe Peek::Views::Rugged, :request_store do
                                                      args: [project.repository.raw, 'HEAD'],
                                                      duration: 0.123)
     ::Gitlab::RuggedInstrumentation.add_call_details(feature: :rugged_test2,
-                                                     args: [project.repository.raw, 'refs/heads/master'],
+                                                     args: [project.repository, 'refs/heads/master'],
                                                      duration: 0.456)
 
     results = subject.results
@@ -32,7 +32,11 @@ describe Peek::Views::Rugged, :request_store do
     expect(results[:duration]).to eq('1234.00ms')
     expect(results[:details].count).to eq(2)
 
-    expect(results[:details][0][:args]).to eq([project.repository.raw.to_s, "refs/heads/master"])
-    expect(results[:details][1][:args]).to eq([project.repository.raw.to_s, "HEAD"])
+    expected = [
+      [project.repository.raw.to_s, "HEAD"],
+      [project.repository.to_s, "refs/heads/master"]
+    ]
+
+    expect(results[:details].map { |data| data[:args] }).to match_array(expected)
   end
 end