From fcd662cba85fa128873e6055f63cf947afe3e5f3 Mon Sep 17 00:00:00 2001
From: Carl-Erik Kopseng <carlerik@gmail.com>
Date: Tue, 16 May 2023 09:46:26 +0200
Subject: [PATCH] fix (#2514): only force new or inherited descriptors to be
 configurable

---
 lib/sinon/util/core/wrap-method.js |  8 +++++++-
 test/issues/issues-test.js         | 26 ++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/lib/sinon/util/core/wrap-method.js b/lib/sinon/util/core/wrap-method.js
index 8acc7eeb3..8ee3a3936 100644
--- a/lib/sinon/util/core/wrap-method.js
+++ b/lib/sinon/util/core/wrap-method.js
@@ -137,7 +137,13 @@ module.exports = function wrapMethod(object, property, method) {
         for (i = 0; i < types.length; i++) {
             mirrorProperties(methodDesc[types[i]], wrappedMethodDesc[types[i]]);
         }
-        methodDesc.configurable = true;
+
+        // you are not allowed to flip the configurable prop on an
+        // existing descriptor to anything but false (#2514)
+        if(!owned) {
+            methodDesc.configurable = true;
+        }
+
         Object.defineProperty(object, property, methodDesc);
 
         // catch failing assignment
diff --git a/test/issues/issues-test.js b/test/issues/issues-test.js
index e616e03a8..6a1b88b05 100644
--- a/test/issues/issues-test.js
+++ b/test/issues/issues-test.js
@@ -873,4 +873,30 @@ describe("issues", function () {
             });
         });
     });
+
+    describe("#2514 (regression from fixing #2491) - writable object descriptors that are unconfigurable should be assignable", function () {
+        function createInstanceWithWritableUconfigurablePropertyDescriptor() {
+            const instance = {};
+            Object.defineProperty(instance, "aMethod", {
+                writable: true,
+                configurable: false,
+                value: function () {
+                    return 42;
+                },
+            });
+
+            return instance;
+        }
+
+        it("should be able to assign and restore unconfigurable descriptors that are writable", function () {
+            const o =
+                createInstanceWithWritableUconfigurablePropertyDescriptor();
+
+            refute.exception(() =>
+                this.sandbox.stub(o, "aMethod").returns("stubbed")
+            );
+            assert.equals("stubbed", o.aMethod());
+            this.sandbox.restore();
+        });
+    });
 });