Robots.txt triggers exception on alternate domains


  • Bug reports MUST include reproduction instructions which allow someone who does not have access to your environment to reproduce the issue you’re encountering.
  • Bug reports MUST be against a recent version of Phabricator, and include version information. You can find version information in “Config > Version Information” in the web UI, or arc version from the CLI.

Reproduction Instructions

  • Configure alternate domain like for file storage
  • browse to /robots.txt on that domain
  • See
    Unhandled Exception (“AphrontMalformedRequestException”)
    This Phabricator install is configured as “”, but you are using the domain name “” to access a page which is trying to set a cookie. Access Phabricator on the configured primary domain or a configured alternate domain. Phabricator will not set cookies on other domains for security reasons.
    Instead of robots file

Phabricator/Arcanist Version
Output from Config > Version Information or arc version.

phabricator 7c44657ca573 Thu, Feb 18
arcanist f501f85eb8bf Wed, Feb 10

While I understand it when setting a cookie, robots.txt is a plain text file and shouldn’t need cookies etc setting

Thanks, I filed this upstream as


This should be fixed by, now in master. See the task above for more details.