Share link doesn’t use domain with german umlaut but punycode domain

My Nextcloud server has an IDN domain with an “ö” in the URL.
it works fine but every time I create a share link, it uses the punycode domain ( https://xn–…-zxa.net/s/…) instead of the correct domain with ö.
Because this is very ugly, i change it by hand each time.

The configuration contains both domains as trusted domains, the one with ö is the first one.
I tried setting overwrite.cli.url and overwritehost but it doesn’t make a difference.

I’m running:
nextcloud 12.0.1~jessie
Debian Jessie 8.9
nginx 1.6.2-5+deb8u5
php 5.6.30+dfsg-0+deb8u1

Is there a way to rewrite the share link or configure it correctly?

Thank you very much!

Florian

PS: The nextcloud windows client doesn’t like hostname in my SSL cert which I had to create with a punycode because let’s encrypt doesn’t seem to support IDNs correctly. But it can be ignored easily.

Steps to reproduce

1. setup nextcloud on a server with a international domain name/IDN
2. create a share link
3. the link contains not the IDN but the punycode domain

Expected behaviour

The share links should use the IDN, in my case with an "ö".

Actual behaviour

The share links contain the punycode domain https://xn–…-zxa.net/s/…

Server configuration

Operating system: Debian Jessie 8.9

Web server: nginx 1.6.2-5+deb8u5

Database: MariaDB

PHP version: php 5.6.30+dfsg-0+deb8u1

Nextcloud version: nextcloud 12.0.1~jessie

Updated from an older Nextcloud/ownCloud or fresh install: updated from 11

Where did you install Nextcloud from: http://apt.jurisic.org/debian/

Signing status:

List of activated apps:

Nextcloud configuration:

</details>

**Are you using external storage, if yes which one:** no

**Are you using encryption:** no

**Are you using an external user-backend, if yes which one:** no

### Client configuration
**Browser:** Chrome

**Operating system:** Win10

No source files or tests are named. Start by reproducing share-link creation with an internationalized domain and inspect how overwritehost, overwrite.cli.url, and trusted_domains feed the generated URL. Done means generated share links use the configured IDN rather than its punycode form, with regression coverage for the reported setup.