fix(tame-metering): quieter warnings for defineProperty failures

Agoric · Dec 19, 2020 · 7575b94 · 7575b94
1 parent 5ed0310
commit 7575b94
Showing 1 changed file with 22 additions and 14 deletions.
diff --git a/packages/tame-metering/src/tame.js b/packages/tame-metering/src/tame.js
@@ -38,6 +38,7 @@ export function tameMetering() {
 
   let globalMeter = null;
   const definePropertyFailures = new Set();
+  const frozenPaths = new Set();
   const wrapped = new WeakMap();
   const setWrapped = (...args) => apply(wmSet, wrapped, args);
   const getWrapped = (...args) => apply(wmGet, wrapped, args);
@@ -228,7 +229,7 @@ export function tameMetering() {
       wrap(getPrototypeOf(target), pname && `${pname}.__proto__`),
     );
 
-    const assignToTarget = (p, desc) => {
+    const assignToWrapper = (p, desc) => {
       let newDesc;
       if (constructor && p === 'constructor') {
         newDesc = {
@@ -240,28 +241,35 @@ export function tameMetering() {
       } else {
         newDesc = wrapDescriptor(desc, pname && `${pname}.${String(p)}`);
       }
-      for (const o of [wrapper, target]) {
-        try {
-          defineProperty(o, p, newDesc);
-        } catch (e) {
-          // Ignore: TypeError: Cannot redefine property: ...
-          const path = pname ? `${pname}.${String(p)}` : '*unknown*';
-          if (!definePropertyFailures.has(path)) {
-            definePropertyFailures.add(path);
-            // This is an intentional use of console.log, not a debugging vestige.
-            console.log(`Cannot meter ${path}`);
-          }
+
+      if (Object.isFrozen(wrapper)) {
+        if (!frozenPaths.has(pname)) {
+          frozenPaths.add(pname);
+          console.log(`Cannot meter frozen ${pname}`);
+        }
+        return;
+      }
+
+      try {
+        defineProperty(wrapper, p, newDesc);
+      } catch (e) {
+        // Ignore: TypeError: Cannot redefine property: ...
+        const path = pname ? `${pname}.${String(p)}` : '*unknown*';
+        if (!definePropertyFailures.has(path)) {
+          definePropertyFailures.add(path);
+          // This is an intentional use of console.log, not a debugging vestige.
+          console.log(`Cannot meter defined ${path}`);
         }
       }
     };
 
     // Assign the wrapped descriptors to the target.
     const tdescs = getOwnPropertyDescriptors(target);
     Object.getOwnPropertyNames(tdescs).forEach(p =>
-      assignToTarget(p, tdescs[p]),
+      assignToWrapper(p, tdescs[p]),
     );
     Object.getOwnPropertySymbols(tdescs).forEach(p =>
-      assignToTarget(p, tdescs[p]),
+      assignToWrapper(p, tdescs[p]),
     );
 
     return wrapper;