hexo报错：can not read a block mapping entry

hexo生成时出现错误：

YAMLException: can not read a block mapping entry; a multiline key may not be an implicit key at line 2, column 5:

$ hexo g
INFO  Start processing
ERROR Process failed: _posts/solution-flask-unicodeencodeerror.md
YAMLException: can not read a block mapping entry; a multiline key may not be an implicit key at line 2, column 5:
    date: 2018-12-23 17:00:11
        ^
    at generateError (/Users/cyto/Library/Mobile Documents/com~apple~CloudDocs/cytoblog/node_modules/js-yaml/lib/js-yaml/loader.js:165:10)

看见报错之后，jio得第二行没错啊，英文冒号，空格，没毛病吖，而且也是hexo自己生成的

然后看上一行，标题比以前的长了些，猜测是不是标题太长了，然后把标题去掉了一些，然后就没报错了……

给自己挖个坑，寒假的时候看一下hexo这块的代码，深入分析一下，为啥会报这么个错，最好还能给提个pull request QVQ