fix(auth): guard isOAuthAuth against undefined/null

src/plugin/auth.test.ts

@@ -21,6 +21,14 @@ describe("isOAuthAuth", () => {
     };
     expect(isOAuthAuth(auth)).toBe(false);
   });
+
+  it("returns false for undefined auth without throwing", () => {
+    expect(isOAuthAuth(undefined)).toBe(false);
+  });
+
+  it("returns false for null auth without throwing", () => {
+    expect(isOAuthAuth(null)).toBe(false);
+  });
 });
 
 describe("parseRefreshParts", () => {

src/plugin/auth.ts

@@ -2,8 +2,8 @@ import type { AuthDetails, OAuthAuthDetails, RefreshParts } from "./types";
 
 const ACCESS_TOKEN_EXPIRY_BUFFER_MS = 60 * 1000;
 
-export function isOAuthAuth(auth: AuthDetails): auth is OAuthAuthDetails {
-  return auth.type === "oauth";
+export function isOAuthAuth(auth: AuthDetails | null | undefined): auth is OAuthAuthDetails {
+  return !!auth && auth.type === "oauth";
 }
 
 /**