Before this commit: When someone sends mail with help of mail_composer(mail.compose.message) without having a mail template set, mail is not deleted after being sent (and causes unwanted/unexpected burden on DB). This bug was introduced with commit[1], where auto deletion was disabled if template is not set on the composer. After this commit: If there is no mail template set on the composer, or if the template is set and 'auto_delete' is enabled on that template, the mail sent from composer will be deleted after being sent successfully. A context key is added to allow controlling this behavior. It is notably use to check query counters differences. commit[1] - https://github.com/odoo/odoo/commit/8a026e26c6ae25e3fdb5369a7fa3343d70fab782#diff-898a3d5c08a567c1a7b82c026a213d796e850e376cbdb1c9e7936409f440d37aR257 Task id: 2484915 PR odoo/odoo#68870 Original Pr #68403 closes odoo/odoo#69203 X-original-commit: d54973ee1b4457e3d1c0c8d9bf226928530d8b30 Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>