Why can't I push this change to my 'main' mercurial repository?

Answer 1

It's warning you that your push would create new remote heads (and in this case branches). If you're okay with that, and it sounds like you are, you can push with push -f.

This check is in there so that if you wanted that case1212 branch to not go back to the main server you could do hg push -r default and then you'd not see this warning and not send case1212.

Once you've done this for case1212 you won't see the warning again since case1212 will already be there.

Newer versions of mercurial make that warning a little less scary sounding in the case where the new head is a new branch.

Answer 2

Mercurial's default behavior prevents you from creating remote branches. If you want to do this, you need to force-push.

Synchronize menu in the window you show, there is an option for force push.