Parsing error when using asciidoctor

[proailurus]

• Gitea version (or commit ref): 1.9.4
• Git version: 2.23.0
• Operating system: openSUSE Tumbleweed 20191012
• Database (use [x]):
• asciidoctor version: 2.0.10
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No
  • Not relevant (the test instance doesn't support AsciiDoc)
• Log gist: (couldn't find anything in logs pertaining to external renderers)

Description

When using asciidoctor as external renderer for AsciiDoc files, a superfluous string appears in the output at the beginning of the file:
lang="en">

This seems to be part of asciidoctor's html output, for some reason gitea doesn't filter it out.
The rest of the AsciiDoc file is displayed correctly in gitea's web interface.

I'm using the default asciidoctor config described here:
https://docs.gitea.io/en-us/external-renderers/

Screenshots

https://i.imgur.com/PBewpAz.png

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs during the next 2 weeks. Thank you for your contributions.

[anthonyvdotbe]

This is a valid issue & shouldn't be closed

[lunny]

There is a new sectioon on https://docs.gitea.io/en-us/external-renderers/ about sanitizer maybe help you.

[anthonyvdotbe]

AFAICT, the purpose of that is to avoid certain attributes from getting stripped by Gitea. To solve this issue, there should be a way to do the exact opposite: tell Gitea to strip certain attributes. I tried with the section below, but it doesn't help:

[markup.sanitizer]
ELEMENT = html
ALLOW_ATTR =
REGEXP =

[anthonyvdotbe]

@lunny this can be closed: it's a duplicate of #8676, which is fixed in v1.11.0