perf: add dynamically loaded cache-dependencies module

This reduces the main bundle size by ⚠️  1.1 MB minified! This bundle is loaded only when caching is enabled.

The reason for this huge reduction is that caching dependencies uses the `@actions/cache` package, which is an extremely large package with big dependencies.

`setup-python` is used in `setup-cpp` as a library. This optimization reduces the bundle size for that package as well.

__tests__/utils.test.ts

@@ -8,7 +8,6 @@ import path from 'path';
 import {
   validateVersion,
   validatePythonVersionFormatForPyPy,
-  isCacheFeatureAvailable,
   getVersionInputFromFile,
   getVersionInputFromPlainFile,
   getVersionInputFromTomlFile,
@@ -16,6 +15,7 @@ import {
   IS_WINDOWS,
   getDownloadFileName
 } from '../src/utils';
+import {isCacheFeatureAvailable} from '../src/cache-dependencies';
 
 jest.mock('@actions/cache');
 jest.mock('@actions/core');

src/cache-dependencies.ts

@@ -0,0 +1,42 @@
+import * as cache from '@actions/cache';
+import * as core from '@actions/core';
+import {getCacheDistributor} from './cache-distributions/cache-factory';
+
+export async function cacheDependencies(cache: string, pythonVersion: string) {
+  if (!isCacheFeatureAvailable()) {
+    return;
+  }
+  const cacheDependencyPath =
+    core.getInput('cache-dependency-path') || undefined;
+  const cacheDistributor = getCacheDistributor(
+    cache,
+    pythonVersion,
+    cacheDependencyPath
+  );
+  await cacheDistributor.restoreCache();
+}
+
+export function isGhes(): boolean {
+  const ghUrl = new URL(
+    process.env['GITHUB_SERVER_URL'] || 'https://github.com'
+  );
+  return ghUrl.hostname.toUpperCase() !== 'GITHUB.COM';
+}
+
+export function isCacheFeatureAvailable(): boolean {
+  if (cache.isFeatureAvailable()) {
+    return true;
+  }
+
+  if (isGhes()) {
+    core.warning(
+      'Caching is only supported on GHES version >= 3.5. If you are on a version >= 3.5, please check with your GHES admin if the Actions cache service is enabled or not.'
+    );
+    return false;
+  }
+
+  core.warning(
+    'The runner was not able to contact the cache service. Caching will be skipped'
+  );
+  return false;
+}

src/setup-python.ts

@@ -5,9 +5,7 @@ import * as finderGraalPy from './find-graalpy';
 import * as path from 'path';
 import * as os from 'os';
 import fs from 'fs';
-import {getCacheDistributor} from './cache-distributions/cache-factory';
 import {
-  isCacheFeatureAvailable,
   logWarning,
   IS_MAC,
   getVersionInputFromFile,
@@ -22,17 +20,6 @@ function isGraalPyVersion(versionSpec: string) {
   return versionSpec.startsWith('graalpy');
 }
 
-async function cacheDependencies(cache: string, pythonVersion: string) {
-  const cacheDependencyPath =
-    core.getInput('cache-dependency-path') || undefined;
-  const cacheDistributor = getCacheDistributor(
-    cache,
-    pythonVersion,
-    cacheDependencyPath
-  );
-  await cacheDistributor.restoreCache();
-}
-
 function resolveVersionInputFromDefaultFile(): string[] {
   const couples: [string, (versionFile: string) => string[]][] = [
     ['.python-version', getVersionInputFromPlainFile]
@@ -140,7 +127,8 @@ async function run() {
       }
       core.endGroup();
       const cache = core.getInput('cache');
-      if (cache && isCacheFeatureAvailable()) {
+      if (cache) {
+        const {cacheDependencies} = await import('./cache-dependencies');
         await cacheDependencies(cache, pythonVersion);
       }
     } else {

src/utils.ts

@@ -1,5 +1,4 @@
 /* eslint no-unsafe-finally: "off" */
-import * as cache from '@actions/cache';
 import * as core from '@actions/core';
 import fs from 'fs';
 import * as path from 'path';
@@ -112,31 +111,6 @@ export function validatePythonVersionFormatForPyPy(version: string) {
   return re.test(version);
 }
 
-export function isGhes(): boolean {
-  const ghUrl = new URL(
-    process.env['GITHUB_SERVER_URL'] || 'https://github.com'
-  );
-  return ghUrl.hostname.toUpperCase() !== 'GITHUB.COM';
-}
-
-export function isCacheFeatureAvailable(): boolean {
-  if (cache.isFeatureAvailable()) {
-    return true;
-  }
-
-  if (isGhes()) {
-    core.warning(
-      'Caching is only supported on GHES version >= 3.5. If you are on a version >= 3.5, please check with your GHES admin if the Actions cache service is enabled or not.'
-    );
-    return false;
-  }
-
-  core.warning(
-    'The runner was not able to contact the cache service. Caching will be skipped'
-  );
-  return false;
-}
-
 export function logWarning(message: string): void {
   const warningPrefix = '[warning]';
   core.info(`${warningPrefix}${message}`);