vue & vue-template-compiler has different behavior between 2.4.1 & 2.3.4 when compile contents in pre tag

[clancyz]

Version

2.4.1

Reproduction link

https://github.com/clancyz/vue-2.4.1-test.git

Steps to reproduce

I was using prismjs to highlight some codes in .vue files, which covert normal codes to pairs of <span>s.

But when upgrade to Vue&Vue-template-compiler@2.4.1 the code in pre tag has compiled to inline formats.

In Vue&Vue-template-compiler@2.3.4 it works well.

It seems 2.3.4 & 2.4.1 has different behavior in pre tag compilation.

The contents in pre tag: (you can also see it in src/app.vue)

<pre>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>template</span><span class="token punctuation">></span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>x-row</span><span class="token punctuation">></span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>x-col</span>&nbsp;<span class="token attr-name">:span</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>8<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>x-textarea</span>&nbsp;<span class="token attr-name">placeholder</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>Please Insert<span class="token punctuation">"</span></span>&nbsp;<span class="token attr-name">v-model</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>input<span class="token punctuation">"</span></span><span class="token punctuation">></span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>x-textarea</span><span class="token punctuation">></span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>x-col</span><span class="token punctuation">></span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>x-row</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>template</span><span class="token punctuation">></span></span>

</pre>

Demos below were tested in Chrome 59.0.3071.115

Demo in 2.3.4

git clone https://github.com/clancyz/vue-2.4.1-test.git

# install vue2.3.4 and vue-template-compiler 2.3.4
npm install

npm run dev

Which works well.

Here's html contents:

Demo in 2.4.1

# install vue2.3.4 and vue-template-compiler 2.3.4
npm i vue@2.4.1 vue-template-compiler@2.4.1

npm run dev

The demo code is inline now:

Here's html contents:

** By compare two html contents, it seems \n has removed in 2.4.1. **

What is expected?

Codes in pre has correct format

What is actually happening?

Codes in pre was inline in 2.4.1