hg transplant fails - how do I 'fix up the merge' as it suggests?

Question

My branch2274 was branched from default. Rev. 415 was the first commit and it shares an ancestor with the rev. 412 on the default branch.

Branch2274 is a bug fix which needs merging into default soon BUT I did a very silly thing - I merged in changes from a feature branch (at rev. 418)

In simple terms, I need to undo whatever changes were brought in by rev. 418. There seems to be a lot of ways to attempt this but I'm struggling to get any of them to work:

Mercurial queues attempt:

I've tried importing revs 415, 416, 417, (skipping 418), 421, 428 into a patch queue so I can apply it to rev 425.

Problem: tortoisehg will only allow me to import revs 428, 421 but importing 417 is greyed out but importing 418 just gives me the error "abort: cannot import merge revision 418"

Transplant attempt:

patching file Portal/Instructor/Login.aspx.vb
Hunk #1 FAILED at 18
1 out of 1 hunks FAILED -- saving rejects to file Portal/Instructor/Login.aspx.vb.rej
applying 66b6b089ee01
abort: Fix up the merge and run hg transplant --continue
patch failed to apply

[command interrupted]

Login.aspx.vb has been changed on default and I understand why the merge has failed.

How do I 'fix up' the merge?

Alternatively, is there a simpler way for me to take rev. 418 and tell mercurial to undo the changes it brought in with a new commit on case2274?

Answer 1

In the interests of not leaving a question unanswered (!), I managed to resolve this and the ultimate answer is that there's no simple way to resolve it automatically. Transplant deals in patches, differences between two files but doesn't take into account the common ancestry of the two files so struggles to know what to do when a file has been changed by two people in the same place.

The solution is to load the file in your text editor and load the .rej file which lists the failed parts of the patch. I just had to put my additions in a sensible place in the code file.

Running:

hg transplant --continue

..allowed me to apply the other patches.

If anyone cares to spend some time expanding this answer with a little insight or a few relevant links, then the answer is theirs.