To see the difference between [font="Courier New"]yii migrate/history[/font] and filenames in your migrations directory
doc_root/yii migrate/history all | cut -c 24- | grep '^m' | tac > /tmp/m1
ls doc_root/migrations/ | grep '^m' | sed 's:\.php$::' | sort > /tmp/m2
diff -y /tmp/m1 /tmp/m2
It’s just a quick hack but it might be handy as a starting point.
A [font="Courier New"]yii migrate/diff[/font] action would be a swell contribution for anyone interested.