fix: make stdout flush on newer versions of Node.js (#501)

* test: add failing test for #497

* fix: created shim that sets stdout/stderr to blocking when we know we're about to exit

* fix: OSX tests need a bit more running time

* fix: for the sake of Browserify, also check for _handle

* chore: pulled setBlocking shim into its own module

lib/usage.js

@@ -5,6 +5,7 @@ var decamelize = require('decamelize')
 var stringWidth = require('string-width')
 var wsize = require('window-size')
 var objFilter = require('./obj-filter')
+var setBlocking = require('set-blocking')
 
 module.exports = function (yargs, y18n) {
   var __ = y18n.__
@@ -37,6 +38,8 @@ module.exports = function (yargs, y18n) {
         f(msg, err)
       })
     } else {
+      if (yargs.getExitProcess()) setBlocking(true)
+
       // don't output failure message more than once
       if (!failureOutput) {
         failureOutput = true

package.json

@@ -20,6 +20,7 @@
     "pkg-conf": "^1.1.2",
     "read-pkg-up": "^1.0.1",
     "require-main-filename": "^1.0.1",
+    "set-blocking": "^1.0.0",
     "string-width": "^1.0.1",
     "window-size": "^0.2.0",
     "y18n": "^3.2.1",
@@ -42,7 +43,7 @@
   },
   "scripts": {
     "pretest": "standard",
-    "test": "nyc --cache mocha --require ./test/before.js --timeout=4000 --check-leaks",
+    "test": "nyc --cache mocha --require ./test/before.js --timeout=8000 --check-leaks",
     "coverage": "nyc report --reporter=text-lcov | coveralls",
     "version": "standard-version"
   },
@@ -69,4 +70,4 @@
   "engine": {
     "node": ">=0.10"
   }
-}
+}

test/fixtures/issue-497.js

@@ -0,0 +1,14 @@
+#!/usr/bin/env node
+var yargs = require('../../index')
+var y = yargs.command('download <url> <files..>', 'make a get HTTP request')
+  .help()
+
+for (var i = 0; i < 1000; i++) {
+  yargs.option('o' + i, {
+    describe: 'option ' + i
+  })
+}
+
+y.argv
+
+console.log('never get here')

test/integration.js

@@ -56,6 +56,20 @@ describe('integration tests', function () {
     })
   })
 
+  // see #497
+  it('flushes all output when --help is executed', function (done) {
+    testCmd('./issue-497.js', [ '--help' ], function (code, stdout) {
+      if (code) {
+        done(new Error('cmd exited with code ' + code))
+        return
+      }
+
+      stdout.should.match(/--o999/)
+      stdout.should.not.match(/never get here/)
+      return done()
+    })
+  })
+
   it('correctly fills positional command args with preceding option', function (done) {
     testCmd('./opt-assignment-and-positional-command-arg.js', ['--foo', 'fOo', 'bar', 'bAz'], function (code, stdout) {
       if (code) {

yargs.js

@@ -11,6 +11,7 @@ var readPkgUp = require('read-pkg-up')
 var pkgConf = require('pkg-conf')
 var requireMainFilename = require('require-main-filename')
 var objFilter = require('./lib/obj-filter')
+var setBlocking = require('set-blocking')
 
 var exports = module.exports = Yargs
 function Yargs (processArgs, cwd, parentRequire) {
@@ -649,6 +650,7 @@ function Yargs (processArgs, cwd, parentRequire) {
 
     // generate a completion script for adding to ~/.bashrc.
     if (completionCommand && ~argv._.indexOf(completionCommand) && !argv[completion.completionKey]) {
+      if (exitProcess) setBlocking(true)
       self.showCompletionScript()
       if (exitProcess) {
         process.exit(0)
@@ -658,6 +660,8 @@ function Yargs (processArgs, cwd, parentRequire) {
     // we must run completions first, a user might
     // want to complete the --help or --version option.
     if (completion.completionKey in argv) {
+      if (exitProcess) setBlocking(true)
+
       // we allow for asynchronous completions,
       // e.g., loading in a list of commands from an API.
       var completionArgs = args.slice(args.indexOf('--' + completion.completionKey) + 1)
@@ -678,12 +682,16 @@ function Yargs (processArgs, cwd, parentRequire) {
     // Handle 'help' and 'version' options
     Object.keys(argv).forEach(function (key) {
       if (key === helpOpt && argv[key]) {
+        if (exitProcess) setBlocking(true)
+
         skipValidation = true
         self.showHelp('log')
         if (exitProcess) {
           process.exit(0)
         }
       } else if (key === versionOpt && argv[key]) {
+        if (exitProcess) setBlocking(true)
+
         skipValidation = true
         usage.showVersion()
         if (exitProcess) {