Can't use backtick code block in "blockquote" tag plugin

[seaoak]

Environment Info

$ hexo version
hexo: 3.2.2
hexo-cli: 1.0.2
os: Linux 4.4.0-45-generic linux x64
http_parser: 2.7.0
node: 6.9.1
v8: 5.1.281.84
uv: 1.9.1
zlib: 1.2.8
ares: 1.10.1-DEV
icu: 57.1
modules: 48
openssl: 1.0.2j
$
$ npm ls --depth 0
[email protected] /home/seaoak/blog/test
tqq [email protected]
tqq [email protected]
tqq [email protected]
tqq [email protected]
tqq [email protected]
tqq [email protected]
tqq [email protected]
tqq [email protected]
tqq [email protected]
mqq [email protected]
$
$ (cd node_modules/hexo && git log HEAD~1...)
commit 1da7ad5c920fb16e182342c4acda7d8a94af31f9
Author: Junliang Huang <[email protected]>
Date:   Tue Dec 6 22:48:55 2016 +0800

    appveyor: add node.js 7 testing environment (#2302)
$
$ perl -ne 'print if /^# Writing/.../^# Category/' _config.yml
# Writing
new_post_name: :title.md # File name of new posts
default_layout: post
titlecase: false # Transform title into titlecase
external_link: true # Open external links in new tab
filename_case: 0
render_drafts: false
post_asset_folder: true
relative_link: false
future: true
highlight:
  enable: true
  line_number: true
  auto_detect: false
  tab_replace:
fancybox: false
marked:
  breaks: false

# Category & Tag
$

For BUG

When a backtick code block exists as contents of a "blockquote" tag plugin,
it is translated to a string "undefined" in HTML.

For example, the following markdown text in a post:

{% blockquote %}
```
This is a test.
```
{% endblockquote %}

is translated to HTML as follows:

<blockquote>undefined
</blockquote>

By the way, other inline markdown syntax is translated well.

For example, the following markdown text in a post:

{% blockquote %}
_aaa_
bbb

```
This is a test.
```

ccc
{% endblockquote %}

is translated to HTML as follows:

<blockquote><p><em>aaa</em>
bbb</p>
undefined
<p>ccc</p>
</blockquote>

I think this behavior is a bug.

p.s. I have a patch for this issue (may make a pull request).

[NoahDragon]

Move discuss to the PR. #2321