Try to use /usr/bin/test or /bin/test to work around missing features.
The builtin "test" of Solaris 8 /bin/sh doesn't understand -nt.
#!/bin/sh
set -e
set -x
# skip commit logs
HGMERGE=tkmerge; export HGMERGE
EDITOR=true; export EDITOR
rm -rf m m1 m2
mkdir m
cd m
echo "m this that"
echo "this" > a
echo "that" > b
hg init
hg addremove
hg commit
echo "a:" `hg dump a` "b:" `hg dump b`
echo
cd ..
echo "m2 this that "
mkdir m2
cd m2
hg branch ../m
hg checkout
echo "a:" `hg dump a` "b:" `hg dump b`
echo
cd ../m
echo "m this1 that "
echo "this1" > a
hg commit
echo "a:" `hg dump a` "b:" `hg dump b`
echo
cd ..
echo "m1 this1 that "
mkdir m1
cd m1
hg branch ../m
hg checkout
echo "a:" `hg dump a` "b:" `hg dump b`
echo
cd ../m1
echo "m1 this1 that1"
echo "that1" > b
hg commit
echo "a:" `hg dump a` "b:" `hg dump b`
echo
cd ../m2
echo "m2 this that2"
echo "that2" > b
hg commit
echo "a:" `hg dump a` "b:" `hg dump b`
echo
cd ../m1
echo "m1:m2 this1 that1 that2"
hg merge ../m2 # b should conflict, a should be fine
echo "a:" `hg dump a` "b:" `hg dump b`
echo
cd ../m2
echo "m2 this2 that2"
echo "this2" > a
hg commit
echo "a:" `hg dump a` "b:" `hg dump b`
echo
cd ../m2
echo "m2:m this12 that2"
hg merge ../m # a should conflict, b should be fine
echo "a:" `hg dump a` "b:" `hg dump b`
echo
# now here's the interesting bit
# if we choose ancestor by file, no conflicts
# otherwise we've got two equally close ancestors, each with a conflict
# if we go back to the root, we'll have both conflicts again
echo "m2:m1 this12 that12"
hg merge ../m1 # should be clean
echo "a:" `hg dump a` "b:" `hg dump b`
echo