[meeting] 2025-10-01 core mailer beta planning

There was one Feedback Session at Drupal Camp Ruhr (notes here: #3534136-56: Requirements and strategy for Core Mailer) and a talk held by @znerol and @Klara (slides). We briefly touched on the environment switching issue (#3536307: Execution environment: Safely run code inside an environment with partially substituted system state / config). That one could be interesting outside of the context of email. Especially for Search API and maybe ECA and others.

The approach in #3539651: Introduce email plugins still is hard to grasp by just reading the code in the merge request. In addition to the MR, the 3539651-email-content-yaml-plugin-all-in-one branch is supposed to serve as a starting point for people attempting to evaluate the proposed changes in their working copy.

We spent some time discussing the email.html.twig template in the merge request. Currently this has theme hook suggestions for module, key and langcode. The template itself works much like entity templates (node, media) where the content key contains a list of fields. Each of them can be shown and hidden individually from within the twig template. Some contrib modules do provide an additional wrapper template in order to simplify responsive email and basic styling. A wrapper template is not yet part of the MR.

The renaming issue #1803948: [META] Adopt the symfony mailer component currently has merge conflicts. They should be resolved next and then hopefully this could become RTBC soon.

The testing issue #3397420: Add a way to capture mails sent through the mailer transport service during tests was RTBC for a couple of weeks. Maybe this is going to be reviewed around the DrupalCon Vienna sprints.

As for the rest of the open issues, it is not too likely that any of them lands in 11.3. This would mean that the mailer module could be removed from core when 11.3 is released (since it is still alpha level and hardly usable in its current state).

@Klara will be at DrupalCon Vienna, @zengenuity proposed a session for DrupalCon Chicago 2026.

Next planning meeting takes place October 29th at 4PM UTC+2.