[18.0][FIX] mail_composer_cc_bcc: email_cc type

[trisdoan]

Context

• Earlier, mail_composer_cc_bcc overrides mail.mail._prepare_outgoing_list() and was putting a comma-joined string into email_to, where native produces a list.
• Hence, mail_tracking re-joins email_to with COMMASPACE, which mangles a value that is already a string.
• PR [18.0][FIX] mail_composer_cc_bcc: emails list #54 fixed it by making format_emails() return the list form

In the same commit, in the same function, email_cc was changed in the opposite direction — from the list form to the joined-string form:

 email_to = format_emails(partner_to)                 # list   — fixed by #54
-email_cc = format_emails(self.recipient_cc_ids)      # list   — was correct
+email_cc = format_emails_str(self.recipient_cc_ids)  # string — regression

So the commit made email_to a list and email_cc a string, in adjacent lines of the same dict.

Solution

restoring the list form so email_cc matches email_to on the line directly

[trisdoan]

Hello @norlinhenrik , could you take a look please?

[norlinhenrik]

        email_cc = format_emails(self.recipient_cc_ids)
        email_bcc = [r.email for r in self.recipient_bcc_ids if r.email]

Maybe email_bcc should be similar to email_cc?

Please install mail_tracking also, and send an email to multiple CC and multiple BCC. If you confirm that it works, I will approve this PR.