fix config selector fallback behaviour

Author: smilkuri

packages/credential-provider-imds/src/fromInstanceMetadata.e2e.spec.ts

@@ -8,7 +8,7 @@ describe("fromInstanceMetadata (Live EC2 E2E Tests)", () => {
   let imdsAvailable = false;
 
   beforeEach(async () => {
-    process.env = { ...originalEnv };
+    process.env = { ...originalEnv, AWS_EC2_INSTANCE_PROFILE_NAME: "foo-profile" };
 
     // Check IMDS availability
     try {
@@ -87,7 +87,6 @@ describe("fromInstanceMetadata (Live EC2 E2E Tests)", () => {
   it("Uses configured profile name from env", async () => {
     if (!imdsAvailable) return;
 
-    process.env.AWS_EC2_INSTANCE_PROFILE_NAME = "foo-profile";
     const provider = fromInstanceMetadata({ timeout: 1000 });
 
     try {

packages/credential-provider-imds/src/fromInstanceMetadata.ts

@@ -211,11 +211,17 @@ export const throwIfImdsTurnedOff = async (profile?: string, logger?: any): Prom
       // Check environment variable
       environmentVariableSelector: (env) => {
         const envValue = env[ENV_IMDS_DISABLED];
+        if (envValue === undefined) {
+          return undefined;
+        }
         return envValue === "true";
       },
       // Check config file
       configFileSelector: (profile) => {
         const profileValue = profile[CONFIG_IMDS_DISABLED];
+        if (profileValue === undefined) {
+          return undefined;
+        }
         return profileValue === "true";
       },
       default: false,