From 865a454a9c426a519bf6a7bb0265380f60e6ecc6 Mon Sep 17 00:00:00 2001
From: Matteo Collina <hello@matteocollina.com>
Date: Mon, 11 Jul 2022 12:59:03 +0200
Subject: [PATCH] Make sure we always start in a microtick (#189)

Signed-off-by: Matteo Collina <hello@matteocollina.com>
Fixes: https://github.com/fastify/fastify/issues/4125
---
 boot.js                |  2 +-
 test/await-use.test.js | 22 ++++++++++++++++++++++
 test/chainable.test.js |  2 +-
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/boot.js b/boot.js
index f6f7c29..bac9fd7 100644
--- a/boot.js
+++ b/boot.js
@@ -334,7 +334,7 @@ Boot.prototype.ready = function (func) {
       throw new AVV_ERR_CALLBACK_NOT_FN('ready', typeof func)
     }
     this._readyQ.push(func)
-    this.start()
+    queueMicrotask(this.start.bind(this))
     return
   }
 
diff --git a/test/await-use.test.js b/test/await-use.test.js
index b8c173d..6cd5db1 100644
--- a/test/await-use.test.js
+++ b/test/await-use.test.js
@@ -270,3 +270,25 @@ test('await use - mix of same and future tick callbacks', async (t) => {
   record += 'ready'
   t.equal(record, 'plugin0|plugin1|plugin2|ready')
 })
+
+test('await use - fork the promise chain', { only: true }, (t) => {
+  t.plan(3)
+  const app = {}
+  boot(app, { autostart: false })
+
+  async function setup () {
+    let set = false
+    await app.use(async function plugin0 () {
+      t.pass('plugin0 init')
+      await sleep(500)
+      set = true
+    })
+    t.equal(set, true)
+  }
+  setup()
+
+  app.ready((err, done) => {
+    t.error(err)
+    done()
+  })
+})
diff --git a/test/chainable.test.js b/test/chainable.test.js
index 67ecc6d..b889456 100644
--- a/test/chainable.test.js
+++ b/test/chainable.test.js
@@ -63,7 +63,7 @@ test('chainable automatically binded', (t) => {
     expose[key] = 'muahah'
 
     boot(app, {
-      expose: expose
+      expose
     })
 
     t.end()