Backport User preferred language from 3372166

Hi @AdamPS,

I saw your message that if someone wants this backported they should raise a working MR. But I found you had already done all the work and I have tested it and it seems to be working great.

I didn't think it was right to make an MR from your work and I also wanted to know if you think it still needs work.

I am happy to do anything to get this backported. Please let me know if you need anything.

Thanks for your work here so far.

For what its worth this combination works:

"drupal/symfony_mailer": "dev-1.x#089cbc1b51543b2495e6d3389cbd8f77d6da8da2"

https://git.drupalcode.org/issue/symfony_mailer-3372166/-/compare/1.x......

I'm confused😃

After upgrading to 1.6.0-beta1 we found emails only send in the sites default language and translated emails do not get sent in the users preferred language.

So has 1.6 made things worse compared with 1.5?? That would be totally different from a backport.

But I found you had already done all the work and I have tested it and it seems to be working great.

For what its worth this combination works:

I don't understand what you tested in #1 or what works in #4. The IS and #4 both have links to comparisons that are huge with 20 changed files.

I am happy to do anything to get this backported. Please let me know if you need anything.

The backport needs to do something similar to this, which is the original fix: https://git.drupalcode.org/project/symfony_mailer/-/merge_requests/107/d.... The key part is the addition of EmailAdjusterManager::build().

However we need to be back-compatible, so we can't add functions to interfaces or add interfaces to classes. It's probably not even possible because EmailAdjusterInterface::setConfiguration() doesn't exist in 1.x. The best you could do is to make a patch for 1.x that is non-BC, and we leave it in this issue without commit. Sites could apply it if they made sure it didn't break anything for them.