fix(sdk): defer home lookup for explicitly configured Linux runtimes

sdk/typescript/src/runtime.ts

@@ -3399,12 +3399,13 @@ export async function resolvePluginPython(
     );
   }
 
-  const home = options.homeDirectory ?? homedir();
-  const cacheDirectory =
-    environmentValue(environment, "XDG_CACHE_HOME", true) ||
-    join(home, ".cache");
   const managedRoots = options.managedRuntimeRoots ?? [
-    join(cacheDirectory, "codex-runtimes", "codex-primary-runtime"),
+    join(
+      environmentValue(environment, "XDG_CACHE_HOME", true) ||
+        join(options.homeDirectory ?? homedir(), ".cache"),
+      "codex-runtimes",
+      "codex-primary-runtime",
+    ),
   ];
   const relativeCandidates =
     process.platform === "win32"
@@ -3872,16 +3873,16 @@ export function expandHome(
   value: string,
   environment: ProcessEnvironment = process.env,
 ): string {
-  const home =
+  const home = () =>
     (process.platform === "win32"
       ? (environmentValue(environment, "USERPROFILE") ??
         environmentValue(environment, "HOME"))
       : (environmentValue(environment, "HOME") ??
         environmentValue(environment, "USERPROFILE"))) ?? homedir();
-  if (value === "~") return home;
-  if (value.startsWith("~/")) return join(home, value.slice(2));
+  if (value === "~") return home();
+  if (value.startsWith("~/")) return join(home(), value.slice(2));
   if (value.startsWith("~\\")) {
-    return join(home, ...value.slice(2).split("\\"));
+    return join(home(), ...value.slice(2).split("\\"));
   }
   return value;
 }

sdk/typescript/tests-ts/api-runtime-storage.test.ts

@@ -23,6 +23,32 @@ import { PLUGIN_ROOT } from "./plugin-root.js";
 const { temporaryDirectory, cleanup } = createApiTestFixtures();
 afterEach(cleanup);
 
+test("preflights with explicit storage paths when the account has no home directory", async () => {
+  const root = await temporaryDirectory();
+  const repository = join(root, "repository");
+  await mkdir(repository);
+  await writeFile(join(repository, "source.py"), "value = 1\n");
+  const client = new TestClient(
+    {},
+    {
+      environment: {
+        CODEX_HOME: join(root, "codex"),
+        CODEX_SECURITY_STATE_DIR: join(root, "state"),
+      },
+    },
+  );
+  const home = spyOn(os, "homedir").mockImplementation(() => {
+    throw new Error("No home directory for this account");
+  });
+  try {
+    const scan = await client.preflight(repository, { target: ["source.py"] });
+    expect(scan.target.paths).toEqual(["source.py"]);
+  } finally {
+    home.mockRestore();
+    await client.close();
+  }
+});
+
 function stubPluginInstall() {
   return spyOn(runtime, "bootstrapPlugin").mockImplementation(
     async (_home, pluginRoot) => ({

sdk/typescript/tests-ts/runtime.test.ts

@@ -6861,6 +6861,11 @@ describe("runtime directories and plugin Python boundary", () => {
 
   testPosix("uses configured, inherited, and managed Python", async () => {
     const root = await temporaryDirectory();
+    using _home = spyOn(await import("node:os"), "homedir").mockImplementation(
+      () => {
+        throw new Error("No home directory for this account");
+      },
+    );
     const configured = join(root, "configured-python");
     await writeFile(
       configured,
@@ -6914,7 +6919,6 @@ describe("runtime directories and plugin Python boundary", () => {
       expect(
         await resolvePluginPython({
           environment: { PATH: "", XDG_CACHE_HOME: cacheDirectory },
-          homeDirectory: join(root, "unused-home"),
         }),
       ).toBe(cachedPython);
     }