Error 400: "Bad Request while connecting to Mercurial repository"
On the administration page you might notice the following error shown in one of your Mercurial projects:
Check for VCS changes completed with errors. jetbrains.vcs.server.api.VcsServiceException: Failed to complete an action for front:front. Failed to collect current revision for front:front. 'hg –config extensions.loadcommandscommandpy=/<Upsource_home_directory>/temp/upsource-analyzer/hg2/load-commands-command.py CMD /<Upsource_home_directory>/temp/upsource-analyzer/hg2/command.args
for command: hg –config ui.interactive=False pull –config extensions.progress= –config
progress.format=topic number –config progress.delay=0 –config progress.assume-tty=True
http://upsource:******@hg.server' command failed.
stderr: abort: HTTP Error 400: Bad Request
Solution
This error may be caused by Nginx failing to proxy large request headers. Increasing header size limit in Nginx configs should resolve the issue. More details about the syntax and the default values can be found in the Nginx documentation.