From 9a42b6380c92a3528a1e47ebf2ed0354e723fea2 Mon Sep 17 00:00:00 2001
From: Mael Le Guen <github@mlg.lgnby.fr>
Date: Wed, 18 Sep 2019 23:20:14 +0200
Subject: [PATCH] fix: async middleware was called twice (#1422)

---
 lib/middleware.js  |  3 +--
 test/middleware.js | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/lib/middleware.js b/lib/middleware.js
index 9f9c19696..56dab7527 100644
--- a/lib/middleware.js
+++ b/lib/middleware.js
@@ -40,8 +40,7 @@ function applyMiddleware (argv, yargs, middlewares, beforeValidation) {
   const beforeValidationError = new Error('middleware cannot return a promise when applyBeforeValidation is true')
   return middlewares
     .reduce((accumulation, middleware) => {
-      if (middleware.applyBeforeValidation !== beforeValidation &&
-          !isPromise(accumulation)) {
+      if (middleware.applyBeforeValidation !== beforeValidation) {
         return accumulation
       }
 
diff --git a/test/middleware.js b/test/middleware.js
index dd6638c4e..5ea318935 100644
--- a/test/middleware.js
+++ b/test/middleware.js
@@ -145,6 +145,36 @@ describe('middleware', () => {
         .exitProcess(false)
         .parse()
     })
+
+    it('calls an async middleware only once for nested subcommands', (done) => {
+      let callCount = 0
+      let argv = yargs('cmd subcmd')
+        .command(
+          'cmd',
+          'cmd command',
+          function (yargs) {
+            yargs.command(
+              'subcmd',
+              'subcmd command',
+              function (yargs) {}
+            )
+          }
+        )
+        .middleware((argv) => new Promise((resolve) => {
+          callCount++
+          resolve(argv)
+        }))
+        .parse()
+
+      if (!(argv instanceof Promise)) done('argv should be a Promise')
+
+      argv
+        .then(() => {
+          callCount.should.equal(1)
+          done()
+        })
+        .catch(err => done(err))
+    })
   })
 
   // see: https://github.com/yargs/yargs/issues/1281