Extended test case to test dirstate length bug fixed in a7e95e3606c7.
+ hg init
+ hg add a
+ hg commit -m ancestor -d 0 0
+ hg commit -m branch1 -d 0 0
+ hg co 0
+ hg commit -m branch2 -d 0 0
+ hg up -m 1
merge: warning: conflicts during merge
merging a
merging a failed!
+ hg id
32e80765d7fe+75234512624c+ tip
something else
=======
something
+ hg status
M a