Only cache the wrapper ZIP, not the exploded dir

Prior to this change, the wrapper cache contained both the downloaded zip
file as well as the exploded wrapper dir. Only the zip file is required,
as Gradle will automatically detect and unpack.

src/cache-wrapper.ts

@@ -7,9 +7,7 @@ import * as cache from '@actions/cache'
 
 import * as github from './github-utils'
 
-const WRAPPER_CACHE_KEY = 'WRAPPER_CACHE_KEY'
-const WRAPPER_CACHE_PATH = 'WRAPPER_CACHE_PATH'
-const WRAPPER_CACHE_RESULT = 'WRAPPER_CACHE_RESULT'
+const WRAPPER_SLUG = 'WRAPPER_SLUG'
 
 export async function restoreCachedWrapperDist(
     gradlewDirectory: string | null
@@ -17,68 +15,62 @@ export async function restoreCachedWrapperDist(
     if (isWrapperCacheDisabled()) return
     if (gradlewDirectory == null) return
 
-    const wrapperSlug = extractGradleWrapperSlugFrom(
-        path.join(
+    const wrapperProperties = path.join(
         path.resolve(gradlewDirectory),
         'gradle/wrapper/gradle-wrapper.properties'
     )
-    )
-    if (!wrapperSlug) return
-
-    const wrapperCacheKey = `wrapper-${wrapperSlug}`
-    const wrapperCachePath = path.resolve(
-        os.homedir(),
-        `.gradle/wrapper/dists/gradle-${wrapperSlug}`
-    )
-    if (fs.existsSync(wrapperCachePath)) return
-
-    core.saveState(WRAPPER_CACHE_KEY, wrapperCacheKey)
-    core.saveState(WRAPPER_CACHE_PATH, wrapperCachePath)
-
-    try {
-        const restoredKey = await cache.restoreCache(
-            [wrapperCachePath],
-            wrapperCacheKey
-        )
-
-        if (!restoredKey) {
-            core.info(
-                'Wrapper installation cache not found, expect a Gradle distribution download.'
+    const wrapperSlug = extractGradleWrapperSlugFrom(wrapperProperties)
+    if (!wrapperSlug) {
+        core.warning(
+            `Could not calculate wrapper version from ${wrapperProperties}`
         )
         return
     }
 
-        core.saveState(WRAPPER_CACHE_RESULT, restoredKey)
+    const wrapperDir = getWrapperDir(wrapperSlug)
+    const cacheKey = getCacheKey(wrapperSlug)
+    const cachePath = getCachePath(wrapperSlug)
+
+    // Check if the wrapper has already been downloaded to Gradle User Home
+    if (fs.existsSync(wrapperDir)) return
+
+    try {
+        const restoredKey = await cache.restoreCache([cachePath], cacheKey)
+
+        if (restoredKey) {
             core.info(
                 `Wrapper installation restored from cache key: ${restoredKey}`
             )
-        return
+        } else {
+            core.info(
+                `Wrapper installation cache not found. Will download and cache with key: ${cacheKey}.`
+            )
+            // Save the slug to trigger caching of the downloaded wrapper
+            core.saveState(WRAPPER_SLUG, wrapperSlug)
+        }
     } catch (error) {
         core.info(
-            `Wrapper installation cache restore failed, expect a Gradle distribution download\n  ${error}`
+            `Wrapper installation cache restore failed for key: ${cacheKey}.\n  ${error}`
         )
-        return
     }
 }
 
 export async function cacheWrapperDist(): Promise<void> {
     if (isWrapperCacheDisabled()) return
 
-    const cacheKey = core.getState(WRAPPER_CACHE_KEY)
-    const cachePath = core.getState(WRAPPER_CACHE_PATH)
-    const cacheResult = core.getState(WRAPPER_CACHE_RESULT)
+    const wrapperSlug = core.getState(WRAPPER_SLUG)
+    if (!wrapperSlug) return
 
-    if (!cachePath || !fs.existsSync(cachePath)) {
-        core.debug('No wrapper installation to cache.')
+    const wrapperDir = getWrapperDir(wrapperSlug)
+    const cacheKey = getCacheKey(wrapperSlug)
+    const cachePath = getCachePath(wrapperSlug)
+
+    if (!fs.existsSync(wrapperDir)) {
+        core.warning(`No wrapper installation to cache at ${wrapperDir}`)
         return
     }
 
-    if (cacheResult && cacheKey === cacheResult) {
-        core.info(
-            `Wrapper installation cache hit occurred on the cache key ${cacheKey}, not saving cache.`
-        )
-        return
-    }
+    core.info(`Will cache wrapper zip ${cachePath} with key ${cacheKey}`)
 
     try {
         await cache.saveCache([cachePath], cacheKey)
@@ -117,3 +109,21 @@ export function extractGradleWrapperSlugFromDistUri(
 function isWrapperCacheDisabled(): boolean {
     return !github.inputBoolean('wrapper-cache-enabled', true)
 }
+
+function getCacheKey(wrapperSlug: string): string {
+    return `wrapper-v1-${wrapperSlug}`
+}
+
+function getWrapperDir(wrapperSlug: string): string {
+    return path.resolve(
+        os.homedir(),
+        `.gradle/wrapper/dists/gradle-${wrapperSlug}`
+    )
+}
+
+function getCachePath(wrapperSlug: string): string {
+    return path.resolve(
+        os.homedir(),
+        `.gradle/wrapper/dists/gradle-${wrapperSlug}/*/gradle-${wrapperSlug}.zip`
+    )
+}