test(lua): benchmark compiled script cache on vs off

Use the bundled argoproj.io/Rollout health script (~5 KB) with real
testdata so the benchmark reflects compile cost on representative checks.

Co-authored-by: Cursor <cursoragent@cursor.com>
Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

Author: crenshaw-dev

util/lua/script_cache_test.go

@@ -2,14 +2,24 @@ package lua
 
 import (
 	"fmt"
+	"os"
 	"testing"
 
 	lua "github.com/yuin/gopher-lua"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"sigs.k8s.io/yaml"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
+const (
+	// Rollout is a representative built-in health script: ~5 KB of Lua with helper
+	// functions and multiple code paths, similar in complexity to hot-path checks.
+	scriptCacheBenchScriptPath = "../../resource_customizations/argoproj.io/Rollout/health.lua"
+	scriptCacheBenchObjPath    = "../../resource_customizations/argoproj.io/Rollout/testdata/canary/healthy_executedAllSteps.yaml"
+)
+
 const cacheTestScriptA = `local hs = {}
 hs.status = "Healthy"
 hs.message = "a"
@@ -81,3 +91,50 @@ func TestCompiledScriptCache_OnOffParity(t *testing.T) {
 
 	assert.Equal(t, off, on, "cache must not change health output")
 }
+
+func loadScriptCacheBenchFixtures(tb testing.TB) (script string, obj *unstructured.Unstructured) {
+	tb.Helper()
+	scriptBytes, err := os.ReadFile(scriptCacheBenchScriptPath)
+	require.NoError(tb, err)
+	yamlBytes, err := os.ReadFile(scriptCacheBenchObjPath)
+	require.NoError(tb, err)
+	objMap := make(map[string]any)
+	require.NoError(tb, yaml.Unmarshal(yamlBytes, &objMap))
+	return string(scriptBytes), &unstructured.Unstructured{Object: objMap}
+}
+
+func BenchmarkExecuteHealthLuaScriptCache(b *testing.B) {
+	script, obj := loadScriptCacheBenchFixtures(b)
+	vm := VM{}
+
+	for _, mode := range []struct {
+		name    string
+		enabled bool
+	}{
+		{"cacheOff", false},
+		{"cacheOn", true},
+	} {
+		b.Run(mode.name, func(b *testing.B) {
+			origEnabled := scriptCacheEnabled
+			origCache := compiledScripts
+			scriptCacheEnabled = mode.enabled
+			if mode.enabled {
+				compiledScripts = newCompiledScriptCache()
+				if _, err := vm.ExecuteHealthLua(obj, script); err != nil {
+					b.Fatal(err)
+				}
+			}
+			b.Cleanup(func() {
+				scriptCacheEnabled = origEnabled
+				compiledScripts = origCache
+			})
+
+			b.ReportAllocs()
+			for b.Loop() {
+				if _, err := vm.ExecuteHealthLua(obj, script); err != nil {
+					b.Fatal(err)
+				}
+			}
+		})
+	}
+}