I commit something to my local Mercurial repository and write the log message containing some umlauts using nano. I then push the changes to Phabricator. The resulting email contains ? in subject and body, even though it has following headers set:
MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="utf-8"
Within Phabricator, the commit message also shows ? instead of the umlauts. The generated site has <meta charset="UTF-8">.
Looking at the Mercurial repository on the server directly (using hg log), the umlauts are displayed properly.
I have set LANG=en_GB.UTF-8 on my local system. The server supports the same locale. PHP has default_charset = "UTF-8" set.
The issue appears with HHVM 3.5.0 as well as PHP-FPM 5.5.21. It also showed (on the web and in emails) with old commits that were created when we were still using mod_php. I am running Apache 2.4.10-9 and MariaDB 10.0.15-3 on Debian 8 Jessie. The Mercurial versions involved are 3.0.1 (client) and 3.1.2 (server).