fix(plugin-sdk): stop library import warmup side effects

src/plugin-sdk/root-alias.cjs

@@ -113,6 +113,13 @@ const fastExports = {
 const target = { ...fastExports };
 let rootExports = null;
 
+function shouldResolveMonolithic(prop) {
+  if (typeof prop !== "string") {
+    return false;
+  }
+  return prop !== "then";
+}
+
 function getMonolithicSdk() {
   const loaded = tryLoadMonolithicSdk();
   if (loaded && typeof loaded === "object") {
@@ -125,6 +132,9 @@ function getExportValue(prop) {
   if (Reflect.has(target, prop)) {
     return Reflect.get(target, prop);
   }
+  if (!shouldResolveMonolithic(prop)) {
+    return undefined;
+  }
   const monolithic = getMonolithicSdk();
   if (!monolithic) {
     return undefined;
@@ -137,6 +147,9 @@ function getExportDescriptor(prop) {
   if (ownDescriptor) {
     return ownDescriptor;
   }
+  if (!shouldResolveMonolithic(prop)) {
+    return undefined;
+  }
 
   const monolithic = getMonolithicSdk();
   if (!monolithic) {
@@ -166,6 +179,9 @@ rootExports = new Proxy(target, {
     if (Reflect.has(target, prop)) {
       return true;
     }
+    if (!shouldResolveMonolithic(prop)) {
+      return false;
+    }
     const monolithic = getMonolithicSdk();
     return monolithic ? Reflect.has(monolithic, prop) : false;
   },

src/plugin-sdk/root-alias.test.ts

@@ -109,6 +109,17 @@ describe("plugin-sdk root alias", () => {
     expect(lazyModule.jitiLoadCalls).toBe(0);
   });
 
+  it("does not load the monolithic sdk for promise-like or symbol reflection probes", () => {
+    const lazyModule = loadRootAliasWithStubs();
+    const lazyRootSdk = lazyModule.moduleExports;
+
+    expect("then" in lazyRootSdk).toBe(false);
+    expect(Reflect.get(lazyRootSdk, Symbol.toStringTag)).toBeUndefined();
+    expect(Object.getOwnPropertyDescriptor(lazyRootSdk, Symbol.toStringTag)).toBeUndefined();
+    expect(lazyModule.createJitiCalls).toBe(0);
+    expect(lazyModule.jitiLoadCalls).toBe(0);
+  });
+
   it("loads legacy root exports on demand and preserves reflection", () => {
     const lazyModule = loadRootAliasWithStubs({
       monolithicExports: {