Tentative checkin for branch only, not to be merged?

Here's another: Working on a branch, I just did a pull, and merged from trunk onto the beranch. I notice that somebody else has a minor bug on the trunk: it looks like they forgot to check in a test reference pattern, although it is also possible that the test has been checked in before the golden behavior is established. I report the bug. But I would like to silence the error, at least on my branch. I can make the change to the reference patterns. However, I do not know if that change is goosd. I just want to silence it, or mark it as a known error. I don't want my change to propagate back to the trunk when eventually I merge and push. I.e. my branch now contains some tentative stuff, as well as some stuff that I am confident will soon be merghed. On CVS I would create a per file branch for the reference, and work off a merged directory. Eventually, I would update to the main branch, ahnd not get5 my patched test. Unclear how to do this in Mercurial, apart from remembering that I have to delete it eventually. Oh, here's a way:

// working on branch B
hg pull
hg merge -r tip
make test
// make change to silence test error
hg branch Bb
// somehow copy old version of patched file to pre brahnch
hg ci // on Bb
hg update -r B
// now work
// when ready to merge, do the usual
hg pull
hg merge
make test
// now do the extra step to be confident that you aren't pushing anything broken
hg update -r Bb
hg merge -r B
// now should have B, except for that one change that was tenative
make test
// see if the bug was fixed by someone else...
// ok, now merge to default branch, and then push
// - since I am paranoid, I might pull and test again
hg update -r default
hg merge -r Bb
make test
hg push

Works, but is complicated. I am quite likely to forget that I am supposed to merge from branch B onto Bb before merging to the trunk. {{Category-VCS}}{{Category-hg}}