Message-ID header missing in follow-up email notifications

[mxmehl]

Gitea Version

1.15.3

Git Version

2.30.2

Operating System

Debian 10

How are you running Gitea?

Binary packages running via systemd

Database

MySQL

Can you reproduce the bug on the Gitea demo site?

Yes

Log Gist

No response

Description

The first notification mail of an issue or pull request contains a valid Message-ID header, e.g. Message-ID: <fsfe-system-hackers/baseline/issues/10@git.fsfe.org>.

However, all following mails do not carry this header for some reason. This is bad because it does not conform with RFC 5322, and spam filters often downrate it or even not not let it pass (in RSPAMD: MISSING_MID(2.5)).

Not sure whether it relates to #13065.

Screenshots

No response

[KN4CK3R]

However, all following mails do not carry this header for some reason.

The reason is the comment
// Set Message-ID on first message so replies know what to reference
but that's wrong. Will be fixed with #17206.