Revision 107 accidentally merged away all the changes from 100-106
Revision 108 was a hg revert --all -r 106, followed by hg commit, which was probably the wrong thing to do, since instead of merging the branch where I made all the changes, I've encompassed all the changes into one changeset with no description or history.
A) How should I have gone about merging the branch in the first place?
But more importantly:
B) How do I go about merging the branch now?
If at all possible, back-up the repository, so that you can experiment safely.
This command will undo the last transaction:
hg rollback -h
This command might help you to undo your merge and revert:
hg backout -h
This command will recover your working directory to a previous state without affecting the repository:
hg revert -h
The -h option in each case gives you the help for the command. Remove the -h option when you are ready to apply the command.
My first experiment would be:
hg rollback
hg merge -r 106
The plan being to get back to revision 107, which looks like a successful merge of the head containing changesets 95 and 96, and then to merge in the head containing changesets 97, 100 - 106.
If you've not yet pushed the repo anywhere off your box you have an easy fix:
cd ..
hg clone -r 106 current newcurrent
cd newcurrent
hg pull -r 97 ../current
now newcurrent is a repo that looks exactly like your old one did before 107 and 108 happened.
To merge those two, just do:
hg update # which gets you to tip
hg merge # which merges in the other head and forces you to make choices
It's not clear what you did wrong in creating 107, so I don't know how to suggest a change in practice, but it should be a simple matter of merging. Accidentally eliminating all the changes in one branch should have been hard.