<h1 dir="auto">Bug report</h1>
<h2 dir="auto">Describe the bug</h2>
<p dir="auto">Scripts in the Head are run twice if marked <code class="notranslate">async</code>.</p>
<h2 dir="auto">To Reproduce</h2>
<p dir="auto">Steps to reproduce the behavior:</p>
<ol dir="auto">
<li>Create next app</li>
<li>Create file at <code class="notranslate">/static/log.js</code> with <code class="notranslate">console.log('hello');</code> inside</li>
<li>Attach to a page (make sure to add the <code class="notranslate">async</code> attribute)</li>
</ol>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="&lt;NextHead&gt;
  &lt;script src=&quot;/static/log.js&quot; async&gt;&lt;/script&gt;
&lt;/NextHead&gt;"><pre class="notranslate"><code class="notranslate">&lt;NextHead&gt;
  &lt;script src="/static/log.js" async&gt;&lt;/script&gt;
&lt;/NextHead&gt;
</code></pre></div>
<ol start="4" dir="auto">
<li>Run site</li>
<li>See duplicate console.log in console.</li>
</ol>
<h2 dir="auto">Expected behavior</h2>
<p dir="auto">Scripts should only run once.</p>
<h2 dir="auto">Screenshots</h2>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/3136271/66759472-36013800-ee98-11e9-9157-86b2e395adda.jpg"><img src="https://user-images.githubusercontent.com/3136271/66759472-36013800-ee98-11e9-9157-86b2e395adda.jpg" alt="Screen Shot 2019-10-14 at 3 34 44 PM" style="max-width: 100%;"></a></p>
<h2 dir="auto">System information</h2>
<ul dir="auto">
<li>OS: macOS</li>
<li>Version of Next.js: latest 9.1.1</li>
</ul>
<p dir="auto">When starting the next build, nothing is shown for a good amount of time. This has caused several misunderstandings with newer developers and is fairly annoying to have no idea how much longer your build will take.</p>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have searched the <a href="https://github.com/zeit/next.js/issues?q=is%3Aissue">issues</a> of this repository and believe that this is not a duplicate.</li>
</ul>
<h2 dir="auto">Expected Behavior</h2>
<p dir="auto">I would expect something in the next.config like showBuildOutput: true that will show some indication of how far along the build is in the terminal or even a progress bar.</p>
<h2 dir="auto">Current Behavior</h2>
<p dir="auto">Currently, you're staring at a nonchanging terminal window for a few minutes if the build takes a while.</p>
<h2 dir="auto">Context</h2>
<p dir="auto">This could be considered a quality of life improvement but is something that I personally would expect to be a fundemental feature of any build.</p>