Use tc.find() with the effective tool cache path

* So it finds already-download prebuilt Ruby in the GH-hosted tool cache path
  on self-hosted, where $RUNNER_TOOL_CACHE is often different than on GH-hosted.
* See #475.
* This relies on tc.find() looking up the env var every time:
  https://github.com/actions/toolkit/blob/1f4b3fac06/packages/tool-cache/src/tool-cache.ts#L522

common.js

@@ -5,6 +5,7 @@ const util = require('util')
 const stream = require('stream')
 const crypto = require('crypto')
 const core = require('@actions/core')
+const tc = require('@actions/tool-cache')
 const { performance } = require('perf_hooks')
 const linuxOSInfo = require('linux-os-info')
 import macosRelease from 'macos-release'
@@ -264,7 +265,18 @@ function getDefaultToolCachePath() {
   }
 }
 
-export function engineToToolCacheName(engine) {
+// tc.find() but using RUNNER_TOOL_CACHE=getToolCachePath()
+export function toolCacheFind(engine, version) {
+  const originalToolCache = getToolCachePath()
+  process.env['RUNNER_TOOL_CACHE'] = getToolCachePath()
+  try {
+    return tc.find(engineToToolCacheName(engine), version)
+  } finally {
+    process.env['RUNNER_TOOL_CACHE'] = originalToolCache
+  }
+}
+
+function engineToToolCacheName(engine) {
   return {
     ruby: 'Ruby',
     jruby: 'JRuby',

dist/index.js

@@ -289,7 +289,6 @@ __nccwpck_require__.r(__webpack_exports__);
 __nccwpck_require__.d(__webpack_exports__, {
   "createToolCacheCompleteFile": () => (/* binding */ createToolCacheCompleteFile),
   "drive": () => (/* binding */ drive),
-  "engineToToolCacheName": () => (/* binding */ engineToToolCacheName),
   "floatVersion": () => (/* binding */ floatVersion),
   "getOSNameVersionArch": () => (/* binding */ getOSNameVersionArch),
   "getRunnerToolCache": () => (/* binding */ getRunnerToolCache),
@@ -313,6 +312,7 @@ __nccwpck_require__.d(__webpack_exports__, {
   "targetRubyVersion": () => (/* binding */ targetRubyVersion),
   "time": () => (/* binding */ time),
   "toolCacheCompleteFile": () => (/* binding */ toolCacheCompleteFile),
+  "toolCacheFind": () => (/* binding */ toolCacheFind),
   "win2nix": () => (/* binding */ win2nix),
   "windows": () => (/* binding */ windows)
 });
@@ -362,6 +362,7 @@ const util = __nccwpck_require__(3837)
 const stream = __nccwpck_require__(2781)
 const common_crypto = __nccwpck_require__(6113)
 const core = __nccwpck_require__(2186)
+const tc = __nccwpck_require__(7784)
 const { performance } = __nccwpck_require__(4074)
 const linuxOSInfo = __nccwpck_require__(8487)
 ;
@@ -621,6 +622,17 @@ function getDefaultToolCachePath() {
   }
 }
 
+// tc.find() but using RUNNER_TOOL_CACHE=getToolCachePath()
+function toolCacheFind(engine, version) {
+  const originalToolCache = getToolCachePath()
+  process.env['RUNNER_TOOL_CACHE'] = getToolCachePath()
+  try {
+    return tc.find(engineToToolCacheName(engine), version)
+  } finally {
+    process.env['RUNNER_TOOL_CACHE'] = originalToolCache
+  }
+}
+
 function engineToToolCacheName(engine) {
   return {
     ruby: 'Ruby',
@@ -68284,7 +68296,7 @@ function getAvailableVersions(platform, engine) {
 async function install(platform, engine, version) {
   let rubyPrefix, inToolCache
   if (common.shouldUseToolCache(engine, version)) {
-    inToolCache = tc.find(common.engineToToolCacheName(engine), version)
+    inToolCache = common.toolCacheFind(engine, version)
     if (inToolCache) {
       rubyPrefix = inToolCache
     } else {
@@ -68498,7 +68510,7 @@ async function install(platform, engine, version) {
 
   let rubyPrefix, inToolCache
   if (common.shouldUseToolCache(engine, version)) {
-    inToolCache = tc.find(common.engineToToolCacheName(engine), version)
+    inToolCache = common.toolCacheFind(engine, version)
     if (inToolCache) {
       rubyPrefix = inToolCache
     } else {

ruby-builder.js

@@ -20,7 +20,7 @@ export function getAvailableVersions(platform, engine) {
 export async function install(platform, engine, version) {
   let rubyPrefix, inToolCache
   if (common.shouldUseToolCache(engine, version)) {
-    inToolCache = tc.find(common.engineToToolCacheName(engine), version)
+    inToolCache = common.toolCacheFind(engine, version)
     if (inToolCache) {
       rubyPrefix = inToolCache
     } else {

windows.js

@@ -49,7 +49,7 @@ export async function install(platform, engine, version) {
 
   let rubyPrefix, inToolCache
   if (common.shouldUseToolCache(engine, version)) {
-    inToolCache = tc.find(common.engineToToolCacheName(engine), version)
+    inToolCache = common.toolCacheFind(engine, version)
     if (inToolCache) {
       rubyPrefix = inToolCache
     } else {