https://meta.discourse.org/t/improving-mailman-email-parsing/253041
When mirroring a public mailling list which uses mailman, there were some cases where the incoming email was not associated to the proper user.
As it happens, for various (undertermined) reasons, the email from the sender is often not in the `From` header but can be in any of the following headers: `Reply-To`, `CC`, `X-Original-From`, `X-MailFrom`.
It might be in other headers as well, but those were the ones we found the most reliable.
This header is used by Microsoft Exchange to indicate when certain types of
autoresponses should not be generated for an email.
It triggers our "is this mail autogenerated?" detection, but should not be used
for this purpose.
* DEV: Remove enable_whispers site setting
Whispers are enabled as long as there is at least one group allowed to
whisper, see whispers_allowed_groups site setting.
* DEV: Always enable whispers for admins if at least one group is allowed.
See https://meta.discourse.org/t/discourse-email-messages-are-incorrectly-threaded/233499
for thorough reasoning.
This commit changes how we generate Message-IDs and do email
threading for emails sent from Discourse. The main changes are
as follows:
* Introduce an outbound_message_id column on Post that
is either a) filled with a Discourse-generated Message-ID
the first time that post is used for an outbound email
or b) filled with an original Message-ID from an external
mail client or service if the post was created from an
incoming email.
* Change Discourse-generated Message-IDs to be more consistent
and static, in the format `discourse/post/:post_id@:host`
* Do not send References or In-Reply-To headers for emails sent
for the OP of topics.
* Make sure that In-Reply-To is filled with either a) the OP's
Message-ID if the post is not a direct reply or b) the parent
post's Message-ID
* Make sure that In-Reply-To has all referenced post's Message-IDs
* Make sure that References is filled with a chain of Message-IDs
from the OP down to the parent post of the new post.
We also are keeping X-Discourse-Post-Id and X-Discourse-Topic-Id,
headers that we previously removed, for easier visual debugging
of outbound emails.
Finally, we backfill the `outbound_message_id` for posts that have
a linked `IncomingEmail` record, using the `message_id` of that record.
We do not need to do that for posts that don't have an incoming email
since they are backfilled at runtime if `outbound_message_id` is missing.
The maximum_staged_users_per_email site setting controls how many
staged users will be invited to the topic created from an incoming
email. Previously, it counted only the new staged users.
Under some conditions, replacing an `<img` with `![]()` can break rendering, and make the image disappear.
Context at https://meta.discourse.org/t/152801
It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
This allows text editors to use correct syntax coloring for the heredoc sections.
Heredoc tag names we use:
languages: SQL, JS, RUBY, LUA, HTML, CSS, SCSS, SH, HBS, XML, YAML/YML, MF, ICS
other: MD, TEXT/TXT, RAW, EMAIL
