pass raw backtrace to loggers for errors, not just exceptions

This was just recently changed in #2638140: Error logging should log a backtrace consistently

Why do you need the full backtrace when you already have the string available? I'm also wondering why its important to care about performance in this case. Things are already super bad, when an error is triggered, isn't it?

Okay fair. My only worry is: When we include the backtrace some implementations might try to serialize it directly, which could cause issues, couldn't it?

I haven't read #9 yet, that is a good point.

There is another call to the php logger here: DefaultExceptionHtmlSubscriber::makeSubrequest

I think we need a change record here. To inform loggers that _drupal_log_error will be passing the entire backtrace in.

Also I think if the message contains the word @backtrace the following code might be a bit interesting...

      // PSR3 style placeholders.
      if ($has_psr3) {
        // Keys are not prefixed with anything according to PSR3 specs.
        // If the message is "User {username} created" the variable key will be
        // just "username".
        if (strpos($message, '@' . $key) !== FALSE) {
          $key = '@' . $key;
        }
      }

I think having @backtrace atm would be a bug

I think having @backtrace atm would be a bug

I hope we don't let anyone control the actual message from outside :)

#16 and #21 are both good answers. Committed/pushed to 8.5.x, thanks!

@mfb
Thank you!
I just published it