This would be great. Auto-fill the check-in comment for the pending changes both for a cherry-pick and a merge.

For example something like what git does. Cherry-picking would simply copy the check-in comment from source changeset and append some details.

"Developed stuff / cherry-pick of cs:13 branch master/foobar"

Merge from branch would auto-fill check-in comment as follows.

"Merge from branch master/foobar"

It's laborious and error prone to write these manually and copy paste comments

The auto comment should have the brnach name as well as the branch comment.
This would save a lot of clicks!

Rather than populating the commit comment, if there was an easy way of seeing all the commit comments that contributed to that merge then I think that would achieve the same goal.

Agreed.

I always want a relevant description in all changes and it is laborious and cumbersome to remember or go and find, copy, and paste the descriptions of all relevant changes being brought in with the merge. This becomes more laborious with a workflow that encourages frequent branching and merging.

I think we might really only be wanting automatically adding change descriptions of all changes done in the source branch since the last merge of the source branch into the target branch. Maybe we'd want to exclude descriptions of merge changes done in the source branch but that's trivial to just manually delete from the automatic cumulative description.

I would love for a way to pull all commit comments from each checkin in a branch into the checkin of an integration to main branch but i guess this is duplication at its worst.

Would be a great option to have in preferences! :)