Mercurial: how to remove a line in a file, for the last 4 changesets (not yet pushed) ?

Question

I have a local mercurial repository with 5 commits that still need to be pushed to the server. However, I accidentally included a line in two specific files since the last 4 commits that I really don't want to have in there (nor in one of the changesets).

Is there any practical way to remove those lines in these two files? (apart from throwing away my local repository, cloning the server's copy, and manually reapplying all changes again)

Answer 1

You're going to get a lot of different suggestions (mq, histedit, import/export) that all essentially do the same thing. And they're all going to feel really clunky because mercurial is built around the concept of an immutable history -- changing history is supposed to be hard. That said, as you correctly understand if you haven't yet pushed the csets it's possible. Here's the procedure I'd use -- I prefer it because it requires enabling no extensions:

hg export --git -o ../all-five-csets.patch 0:tip
cd .. # exit the repo
vi all-five-csets.patch # delete the line manually each time it appears (probably only once)
hg init newrepo
cd newrepo
hg import ../all-five-csets.patch
cd ..
mv repo was-repo
mv newrepo repo

All that's happening there is you're exporting the csets to text representations of themselves. Creating a new, empty repo, and then re-importing the csets. I did all of them because you only have five. If you were looking at altering the last 5 of 500, I would have created the newrepo by doing a clone -r which clones "up to a point' and then applied the csets I'd left behind in their edited form via import.

Answer 2

If it's not important for those 5 commits to be be independent change sets, you use hg collapse to collapse them down to a single change set which doesn't contain those lines you want to avoid pushing. I.e.

• Remove the lines you didn't want to include, then commit that change
• Use hg collapse to collapse the last 6 change sets (the existing 5 local ones, plus your new one that just removes those lines)

That will leave you with one change set on your local machine, which won't contain those lines you want to avoid pushing.

A word of warning, be careful with using hg collapse - you want to make sure you don't collapse change sets that have already been pushed to another repository.