Parser fails on tags with one space inside a <pre> tag

[blackjid]

Vue.js version

2.1.10

Reproduction Link

https://jsfiddle.net/blackjid/br2h9pko/1/

Steps to reproduce

Have and element with just one space inside a <pre> tag element.

<div id="app">
  <pre>
    <span> </span>
  </pre>
</div>

and initialize vue in a parent element

new Vue({
  el: '#app'
});

What is Expected?

Vue initializes correctly.

What is actually happening?

An exception is thrown.

vue.js:7105 Uncaught TypeError: Cannot read property 'text' of undefined
    at Object.chars (vue.js:7105)
    at parseHTML (vue.js:6401)
    at parse (vue.js:6923)
    at compile$1 (vue.js:8003)
    at compile$$1 (vue.js:8425)
    at compileToFunctions (vue.js:8458)
    at Vue$3.$mount (vue.js:8536)
    at Vue$3.Vue._init (vue.js:3379)
    at new Vue$3 (vue.js:3427)

What did I try

• Adding a v-pre attribute to the <pre> tag or to a wrapper element. This didn't work either
• Changing the space with a  . This worked, but you don't always control the code that you are bootstrapping vue on.

[blackjid]

A slightly modified test like this one triggers the error.

vue/test/unit/modules/compiler/parser.spec.js

Lines 482 to 490 in 08bd81f

	it('preserve whitespace in <pre> tag', function () {
	const options = extend({}, baseOptions)
	const ast = parse('<pre><code> \n<span>hi</span>\n </code></pre>', options)
	const code = ast.children[0]
	expect(code.children[0].type).toBe(3)
	expect(code.children[0].text).toBe(' \n')
	expect(code.children[2].type).toBe(3)
	expect(code.children[2].text).toBe('\n ')
	})

  it('preserve whitespace in <pre> tag', function () {
    const options = extend({}, baseOptions)
    const ast = parse('<pre><code>  \n<span> </span>\n  </code></pre>', options)
    const code = ast.children[0]
    expect(code.children[0].type).toBe(3)
    expect(code.children[0].text).toBe('  \n')
    expect(code.children[2].type).toBe(3)
    expect(code.children[2].text).toBe('\n  ')
  })

I also pinpoint this line, that has a comment that describes the problem.

vue/packages/vue-template-compiler/build.js

Lines 1373 to 1376 in 80a7cea

	text = inPre || text.trim()
	? decodeHTMLCached(text)
	// only preserve whitespace if its not right after a starting tag
	: preserveWhitespace && children.length ? ' ' : '';

[blackjid]

Hey! thanks!, that was fast!