From b5352fb0978d43a6544f9467b70448a58e7a16e5 Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben.bridgewater@datadoghq.com>
Date: Mon, 8 Dec 2025 14:45:00 +0100
Subject: [PATCH] chore: prevent most double wrapping in shimmer

This prevents double wrapping in case it would happen.
---
 packages/datadog-shimmer/src/shimmer.js | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/packages/datadog-shimmer/src/shimmer.js b/packages/datadog-shimmer/src/shimmer.js
index add93b8b8f8..bdbd0201856 100644
--- a/packages/datadog-shimmer/src/shimmer.js
+++ b/packages/datadog-shimmer/src/shimmer.js
@@ -13,6 +13,8 @@ const skipMethodSize = skipMethods.size
 
 const nonConfigurableModuleExports = new WeakMap()
 
+const safetyMap = new WeakMap()
+
 /**
  * Copies properties from the original function to the wrapped function.
  *
@@ -75,8 +77,17 @@ function copyObjectProperties (original, wrapped, skipKey) {
 function wrapFunction (original, wrapper) {
   if (typeof original !== 'function') return original
 
+  // Safe guard: If the wrapper is identical, we double wrap.
+  // This will not catch all types of double wrapping, just most.
+  const oldWrapper = safetyMap.get(original)
+  if (oldWrapper === wrapper) {
+    return original
+  }
+
   const wrapped = wrapper(original)
 
+  safetyMap.set(wrapped, wrapper)
+
   if (typeof original === 'function') {
     assertNotClass(original)
     copyProperties(original, wrapped)
@@ -138,8 +149,16 @@ function wrap (target, name, wrapper, options) {
 
   assertMethod(target, name, original)
 
+  // Safe guard: If the wrapper is identical, we double wrap.
+  // This will not catch all types of double wrapping, just most.
+  const oldWrapper = safetyMap.get(original)
+  if (oldWrapper === wrapper) {
+    return
+  }
   const wrapped = wrapper(original)
 
+  safetyMap.set(wrapped, wrapper)
+
   copyProperties(original, wrapped)
 
   if (descriptor.writable) {