Resolve Python architecture during input loading

__tests__/cache/restore-cache.test.ts

@@ -1,11 +1,4 @@
-import {
-  afterEach,
-  beforeEach,
-  describe,
-  expect,
-  it,
-  jest,
-} from "@jest/globals";
+import { beforeEach, describe, expect, it, jest } from "@jest/globals";
 import { createSetupInputs } from "../helpers/setup-inputs";
 
 const mockRestoreCache = jest.fn();
@@ -14,7 +7,6 @@ const mockSetOutput = jest.fn();
 const mockGetArch = jest.fn(() => "x86_64");
 const mockGetOSNameVersion = jest.fn(() => "ubuntu-24.04");
 const mockGetPlatform = jest.fn(async () => "unknown-linux-gnu");
-const ORIGINAL_UV_PYTHON_ARCH = process.env.UV_PYTHON_ARCH;
 
 jest.unstable_mockModule("@actions/cache", () => ({
   restoreCache: mockRestoreCache,
@@ -49,21 +41,12 @@ function cacheKeyOutput(): string {
 }
 
 beforeEach(() => {
-  delete process.env.UV_PYTHON_ARCH;
   jest.clearAllMocks();
   mockGetArch.mockReturnValue("x86_64");
   mockGetOSNameVersion.mockReturnValue("ubuntu-24.04");
   mockGetPlatform.mockResolvedValue("unknown-linux-gnu");
 });
 
-afterEach(() => {
-  if (ORIGINAL_UV_PYTHON_ARCH === undefined) {
-    delete process.env.UV_PYTHON_ARCH;
-  } else {
-    process.env.UV_PYTHON_ARCH = ORIGINAL_UV_PYTHON_ARCH;
-  }
-});
-
 describe("restoreCache", () => {
   it("encodes Python version ranges before adding them to the cache key", async () => {
     await restoreCache(createSetupInputs(), ">3.10.11,<3.11");
@@ -95,10 +78,10 @@ describe("restoreCache", () => {
     );
   });
 
-  it("includes an inherited Python architecture in the cache key", async () => {
-    process.env.UV_PYTHON_ARCH = "aarch64";
+  it("includes the resolved Python architecture in the cache key", async () => {
+    const inputs = createSetupInputs({ pythonArch: "aarch64" });
 
-    await restoreCache(createSetupInputs(), "3.14");
+    await restoreCache(inputs, "3.14");
 
     expect(cacheKeyOutput()).toContain("-3.14-python-aarch64-");
   });

__tests__/helpers/setup-inputs.ts

@@ -16,6 +16,7 @@ export function createSetupInputs(
     checksum: "",
     downloadFromAstralMirror: false,
     enableCache: true,
+    exportPythonArch: false,
     githubToken: "",
     ignoreEmptyWorkdir: false,
     ignoreNothingToCache: false,

__tests__/utils/inputs.test.ts

@@ -38,9 +38,7 @@ jest.unstable_mockModule("@actions/core", () => ({
   warning: mockWarning,
 }));
 
-const { CacheLocalSource, loadInputs, resolvePythonArch } = await import(
-  "../../src/utils/inputs"
-);
+const { CacheLocalSource, loadInputs } = await import("../../src/utils/inputs");
 
 function createTempProject(files: Record<string, string> = {}): string {
   const dir = fs.mkdtempSync(path.join(os.tmpdir(), "setup-uv-inputs-test-"));
@@ -108,6 +106,7 @@ describe("loadInputs", () => {
     });
     expect(inputs.pythonDir).toBe("/runner-temp/uv-python-dir");
     expect(inputs.pythonArch).toBe("");
+    expect(inputs.exportPythonArch).toBe(false);
     expect(inputs.venvPath).toBe("/workspace/.venv");
     expect(inputs.manifestFile).toBeUndefined();
     expect(inputs.resolutionStrategy).toBe("highest");
@@ -166,7 +165,7 @@ describe("loadInputs", () => {
 
     const inputs = loadInputs();
     expect(inputs.pythonArch).toBe("x86_64");
-    expect(resolvePythonArch(inputs.pythonArch)).toBe("x86_64");
+    expect(inputs.exportPythonArch).toBe(true);
   });
 
   it.each(["aarch64", "x86_64_v3", ""])(
@@ -176,8 +175,8 @@ describe("loadInputs", () => {
       process.env.UV_PYTHON_ARCH = pythonArch;
 
       const inputs = loadInputs();
-      expect(inputs.pythonArch).toBe("");
-      expect(resolvePythonArch(inputs.pythonArch)).toBe(pythonArch);
+      expect(inputs.pythonArch).toBe(pythonArch);
+      expect(inputs.exportPythonArch).toBe(false);
     },
   );
 

__tests__/utils/python-arch.test.ts

@@ -57,16 +57,16 @@ afterEach(() => {
 
 describe("setupPythonArch", () => {
   it("leaves Python selection alone without an architecture", async () => {
-    await setupPythonArch("/tools/uv", "");
+    await setupPythonArch("/tools/uv", "", false);
 
     expect(mockExecFile).not.toHaveBeenCalled();
     expect(mockExportVariable).not.toHaveBeenCalled();
   });
 
-  it("validates an inherited architecture without exporting it", async () => {
+  it("validates a resolved environment architecture without exporting it", async () => {
     process.env.UV_PYTHON_ARCH = "aarch64";
 
-    await setupPythonArch("/tools/uv", "");
+    await setupPythonArch("/tools/uv", "aarch64", false);
 
     expect(mockExecFile).toHaveBeenNthCalledWith(
       2,
@@ -83,7 +83,7 @@ describe("setupPythonArch", () => {
   it.each(["/runner temp/uv", "C:\\runner temp\\uv.exe"])(
     "validates and exports the architecture using the installed uv: %s",
     async (uvPath) => {
-      await setupPythonArch(uvPath, "x86_64");
+      await setupPythonArch(uvPath, "x86_64", true);
 
       expect(mockExecFile).toHaveBeenNthCalledWith(
         1,
@@ -112,7 +112,7 @@ describe("setupPythonArch", () => {
   it("rejects uv versions that ignore UV_PYTHON_ARCH", async () => {
     mockExecFile.mockReset().mockResolvedValue(success);
 
-    await expect(setupPythonArch("/tools/uv", "x86_64")).rejects.toThrow(
+    await expect(setupPythonArch("/tools/uv", "x86_64", true)).rejects.toThrow(
       "The installed version of uv does not support UV_PYTHON_ARCH",
     );
     expect(mockExecFile).toHaveBeenCalledTimes(1);
@@ -127,7 +127,7 @@ describe("setupPythonArch", () => {
       }),
     );
 
-    await expect(setupPythonArch("/tools/uv", "x86_64")).rejects.toThrow(
+    await expect(setupPythonArch("/tools/uv", "x86_64", true)).rejects.toThrow(
       "Failed to check uv's support for UV_PYTHON_ARCH: error: unrelated configuration error",
     );
     expect(mockExportVariable).not.toHaveBeenCalled();
@@ -144,7 +144,7 @@ describe("setupPythonArch", () => {
         }),
       );
 
-    await expect(setupPythonArch("/tools/uv", "invalid")).rejects.toThrow(
+    await expect(setupPythonArch("/tools/uv", "invalid", true)).rejects.toThrow(
       "Failed to set Python architecture to invalid: error: Unknown architecture: invalid",
     );
     expect(mockExportVariable).not.toHaveBeenCalled();