fix(javascript): retain Reflect set receiver effects

docs/javascript-artifact-reconstruction.md

@@ -349,7 +349,8 @@ argument prefixes and the original bound receiver through `call`, `apply`, and
 creation. Visibly replaced invocation intrinsics produce unknown effects instead
 of using their former call semantics; captured function aliases retain their
 earlier identity. Unexamined
-targets remain unresolved. Creating an unused binding does not itself mutate
+targets remain unresolved. `Reflect.set` examines its explicit receiver as well
+as its target, retaining unknown receiver effects. Creating an unused binding does not itself mutate
 an intrinsic. Variable redeclarations retain a single unconditional initializer
 when they introduce no assignment or second initializer.
 Stable identifier chains to fresh object, array, function,

src/domain/javascript/electronModuleInterop.test.ts

@@ -560,6 +560,14 @@ describe("Electron module interop bound mutators", () => {
     'Reflect.apply = Object.defineProperty; Reflect.apply(Object,"create",{value:customCreate});',
     'const apply = Reflect.apply; Reflect.apply = Object.defineProperty; Reflect.apply(Object,"create",{value:customCreate});',
     'const change = Reflect.set.bind(null,Object,"create"); change(customCreate);',
+    'Reflect.set({},"create",customCreate,Object);',
+    'const metadata = {}; Reflect.set(metadata,"create",customCreate,Object);',
+    'const change = Reflect.set.bind(null,{},"create",customCreate); change(Object);',
+    'Reflect.apply(Reflect.set,null,[{},"create",customCreate,Object]);',
+    'Reflect.set({},"create",customCreate,...receivers);',
+    'Reflect.set({},"create",...valuesAndReceivers);',
+    "Reflect.set({},...keysValuesAndReceivers);",
+    'Reflect.set({},"create",customCreate,receiver);',
     'const change = Object.defineProperty.call; change(null,Object,"create",{value:customCreate});',
     'const {apply:change} = Object.defineProperty; change(null,[Object,"create",{value:customCreate}]);',
     'const change = Reflect.apply.call; change(null,Object.defineProperty,null,[Object,"create",{value:customCreate}]);',
@@ -587,6 +595,8 @@ describe("Electron module interop bound mutators", () => {
     'Object.defineProperty.apply(null,[metadata,"x",{value:1}]);',
     'const change = Object.defineProperty.call; change(null,metadata,"x",{value:1});',
     'const {apply:change} = Object.defineProperty; change(null,[metadata,"x",{value:1}]);',
+    'Reflect.set(metadata,"x",1,{});',
+    'const receiver = {}; Reflect.set({},"x",1,receiver);',
   ])("keeps a fresh bound target or unused binding separate: %s", (write) => {
     expect(
       analyzeJavaScriptStaticSource(

src/domain/javascript/javascriptElectronMemberWrites.ts

@@ -96,25 +96,40 @@ export function* collectJavaScriptIdentityWritesSteps(
           (owner === "Object" && objectMutators.has(method ?? "")) ||
           (owner === "Reflect" && reflectMutators.has(method ?? ""))
         ) {
-          const target = arguments_?.[0];
-          // A known mutator with an opaque argument list can overwrite any
-          // captured intrinsic. Do not turn an unexamined target into proof.
-          if (target === undefined || t.isSpreadElement(target)) {
-            const scope = origin(node, "opaque-call");
-            if (scope !== undefined) retain(node, scope);
-          }
-          if (t.isNode(target) && !t.isSpreadElement(target)) {
-            const { root, members } = electronMemberPath(target);
-            const exported = origin(root, "member");
-            if (exported !== undefined) {
-              const key = keyedMutators.has(method ?? "")
-                ? [staticString(arguments_?.[1]) ?? null]
-                : [];
-              retain(node, [...exported, ...members, ...key]);
-            } else if (!freshObject(target)) {
+          // Reflect.set can write through its explicit receiver as well as
+          // dispatching through its target. Both identities need examination.
+          const targets =
+            owner === "Reflect" &&
+            method === "set" &&
+            arguments_ !== undefined &&
+            (arguments_.length >= 4 || arguments_.some(t.isSpreadElement))
+              ? [
+                  arguments_[0],
+                  arguments_.some(t.isSpreadElement)
+                    ? undefined
+                    : arguments_[3],
+                ]
+              : [arguments_?.[0]];
+          for (const target of targets) {
+            // A known mutator with an opaque argument list can overwrite any
+            // captured intrinsic. Do not turn an unexamined target into proof.
+            if (target === undefined || t.isSpreadElement(target)) {
               const scope = origin(node, "opaque-call");
               if (scope !== undefined) retain(node, scope);
             }
+            if (t.isNode(target) && !t.isSpreadElement(target)) {
+              const { root, members } = electronMemberPath(target);
+              const exported = origin(root, "member");
+              if (exported !== undefined) {
+                const key = keyedMutators.has(method ?? "")
+                  ? [staticString(arguments_?.[1]) ?? null]
+                  : [];
+                retain(node, [...exported, ...members, ...key]);
+              } else if (!freshObject(target)) {
+                const scope = origin(node, "opaque-call");
+                if (scope !== undefined) retain(node, scope);
+              }
+            }
           }
         }
       }

tests/acceptance/applications/electronModuleInteropCli.test.ts

@@ -36,6 +36,7 @@ const INTRINSIC_MUTATIONS = [
     "bound.cjs",
     'const change = Object.defineProperty.bind(null,Object,"create"); change({value:customCreate});',
   ],
+  ["receiver.cjs", 'Reflect.set({},"create",customCreate,Object);'],
 ] as const;
 
 cliTest.for(["CLI", "stdio MCP"] as const)(
@@ -103,6 +104,7 @@ cliTest.for(["CLI", "stdio MCP"] as const)(
       require("./uncurried.cjs");
       require("./generic-bind.cjs");
       require("./replaced-apply.cjs");
+      require("./receiver.cjs");
       throw new Error("must not execute main");
     `;
     await writeFile(join(root, "main.cjs"), source);
@@ -129,7 +131,7 @@ cliTest.for(["CLI", "stdio MCP"] as const)(
       preload_entrypoints: 1,
     });
     expect(result.statistics.parse_failures).toBe(0);
-    expect(result.statistics.parsed_javascript_files).toBe(9);
+    expect(result.statistics.parsed_javascript_files).toBe(10);
     const windows = result.graph.nodes.filter(
       ({ kind }) => kind === "browser-window",
     );