Comment by chungy

The proper solution is that your merge commit should describe exactly what was merged and why. Git pre-fills it with a default "Merge branch-X into branch-Y" message so you can quickly exit the editor and still have a functioning DAG. It's just not ideal to leave it like that, precisely for this reason.

Fossil (https://fossil-scm.org/home/doc/trunk/www/index.wiki) doesn't fill out a default message, and sometimes that has annoyed me, but it does make you think about what you're doing. If you look in the Fossil and SQLite trees, almost all merges include a full description of what the merge was all about and why. Fossil also doesn't forget the entire history of the branch (including from which commit it was branched from), so it has that advantage too.