Steps to replicate the issue (include links if applicable):
- curl https://sr.wikipedia.beta.wmflabs.org/api/rest_v1/page/html/RESTBase_Testing_Page -H 'Accept-Language: sr-el'
What happens?:
We get an Internal Server Error (Status 500).
What should have happened instead?:
We get the page converted to the latin variant, with content-.language sr-el.
Software version (skip for WMF-hosted wikis like Wikipedia):
1.40.0-wmf.4
Other information (browser name/version, screenshots, etc.):
- Impacts PCS, and thereby mobile apps: attempts to load content with variant conversion applied will fail.
- Caused by https://gerrit.wikimedia.org/r/c/mediawiki/core/+/835611. The issue is that the source variant now defaults to the page language ("sr"), instead of staying null.