Don't compile on default if installed via Yarn

prebuild/prebuild#150
prebuild/prebuild#151

Author: lgeiger

bin.js

@@ -7,6 +7,7 @@ var extend = require('xtend')
 
 var rc = require('./rc')
 var download = require('./download')
+var util = require('./util')
 
 var prebuildClientVersion = require('./package.json').version
 if (rc.version) {
@@ -39,15 +40,17 @@ log.info('begin', 'Prebuild-install version', prebuildClientVersion)
 
 var opts = extend(rc, {pkg: pkg, log: log})
 
-if (!(typeof pkg._from === 'string')) {
+var execPath = process.env.npm_execpath || process.env.NPM_CLI_JS
+
+if (util.isYarnPath(execPath) && /node_modules/.test(process.cwd())) {
+  // From yarn repository
+} else if (!(typeof pkg._from === 'string')) {
   log.info('install', 'installing inside prebuild-install directory, skipping download.')
   process.exit(1)
 } else if (pkg._from.length > 4 && pkg._from.substr(0, 4) === 'git+') {
   log.info('install', 'installing from git repository, skipping download.')
   process.exit(1)
-}
-
-if (opts.compile === true || opts.prebuild === false) {
+} else if (opts.compile === true || opts.prebuild === false) {
   log.info('install', '--build-from-source specified, not attempting download.')
   process.exit(1)
 }

test/util-test.js

@@ -160,3 +160,12 @@ test('getDownloadUrl() expands template to correct values', function (t) {
   t.equal(url3, url2, 'scope does not matter for download url')
   t.end()
 })
+
+test('isYarnPath(): returns correct value', function (t) {
+  var yarn = util.isYarnPath
+  t.equal(yarn(null), false)
+  t.equal(yarn(undefined), false)
+  t.equal(yarn('/usr/local/lib/node_modules/npm/bin/npm-cli.js'), false)
+  t.equal(yarn('/usr/local/opt/yarn/libexec/lib/node_modules/yarn/bin/yarn.js'), true)
+  t.end()
+})

util.js

@@ -67,10 +67,15 @@ function localPrebuild (url) {
   return path.join('prebuilds', path.basename(url))
 }
 
+function isYarnPath (execPath) {
+  return execPath ? /^yarn/.test(path.basename(execPath)) : false
+}
+
 exports.getDownloadUrl = getDownloadUrl
 exports.urlTemplate = urlTemplate
 exports.cachedPrebuild = cachedPrebuild
 exports.localPrebuild = localPrebuild
 exports.prebuildCache = prebuildCache
 exports.npmCache = npmCache
 exports.tempFile = tempFile
+exports.isYarnPath = isYarnPath