I use Git pull for the minor point upgrades and have never hit a snag before.
It still showed current version in the footer as 3.6.2
Click anywhere and got the dmlexception db read error. Obviously because new tables/data had not been written to the database. Site was dead.
I successfully used git reset hard, to bring the site back to 3.6.2 where it stands today. Thank you git people!
AWS EC2, Amazon Linux 2, MariaDB