test that a commit clears the merge state.
$ hg init repo
$ cd repo
$ echo foo > file
$ hg commit -Am 'add file'
adding file
$ echo bar >> file
$ hg commit -Am 'append bar'
create a second head
$ hg up -C 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo baz >> file
$ hg commit -Am 'append baz'
created new head
failing merge
$ hg merge --tool=internal:fail
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
[1]
$ echo resolved > file
$ hg resolve -m file
$ hg commit -m 'resolved'
resolve -l, should be empty
$ hg resolve -l
test crashed merge with empty mergestate
$ mkdir .hg/merge
$ touch .hg/merge/state
resolve -l, should be empty
$ hg resolve -l