hg update leads to failed merge - version-control

Let's say I'm at revision n of my repo. I have uncommitted changes. Forgetting about my changes, I update to revision n-1. Normally, mercurial simply merges in my uncommitted changes, and everything goes off without a hitch. But sometimes there are merge conflicts. Now I would have to resolve the conflicts by hand. I would much prefer to recover the state prior to the update. Or better yet, tell mercurial to always abort an update if it runs into merge conflicts during the update. Is there a simple way to do that?

You can use --config ui.merge=internal:fail to NOT attempt a merge that is in both. You would then need to manually merge or use the resolve command.
If using TortoiseHG you can deselect the Always merge option when updating which will cause THG to ask you what it should do. Deselecting the Automatically resolve merge conflicts where possible is the equivalent of internal.fail noted above.

Related

How to do a difficult rebase in O(n) rather than O(n^2)?

There's this difficult rebase that keeps stumbling on conflicts every other commit. In order to be able to resolve some confusing conflicts, I must sometimes --abort and check out the master branch to see what exactly is there (unconfounded by conflict markup, stuff rebased so far, or git's "ours" vs. "theirs" hell). Whenever I do this, I must subsequently re-resolve all conflicts up to that point. This makes the rebase effectively O(n^2).
Is there a better way?
(Note: it absolutely must be a rebase, this requirement is a given. Merging is out of the question).
First, the new (Git 2.30) new merge strategy: ORT ("Ostensibly Recursive's Twin") will be slightly faster.
But the all process would still be not O(n).
Second, do use the git worktree command in order to checkout master in a separate folder (without making a separate clone).
That way, you don't have to abort the merge in progress, and can compare with a copy of your working tree, on master branch.

Using mercurial why would I ever want to merge without committing?

Perhaps I'm biased from years of svn but why would I ever want to merge with a different branch then make some changes before committing. The hg output itself suggests otherwise:
(branch merge, don't forget to commit)
Dear hg, then why didn't you just do it for me?
Because a merge operation is not guaranteed to produce correct output (automatic merges can use bad heuristics for how to deal with conflicts, manual merges can suffer from human error). Usually, what you will do is the following:
Merge.
Build.
Test.
If the test failed, fix the issue, go back to 2.
Commit.
Mercurial does not suggests otherwise, it 's just reminder: "All merge-related changes stored only on Working Dir, commit results into repository for permanent storing" and doesn't prohibit you to make some additional changes in code before commit.
But separation of tasks (merge and not-related to merge changes - i.e changes not initiated by merge-conflicts) into separate changesets is good idea anyway

Rolling back a merge in TFS2008 with tfpt.exe

I need to roll back a merge operation in TFS2008. The branch will need to be merged at a later date. I know I can use the tfpt.exe rollback operation on the trunk to restore the files modified by the merge, but rollback doesn't modify the merge information so future merges from the branch into the trunk won't restore the changes undone by the rollback. Also, merges from the trunk into the branch will risk overwriting changes in the branch.
I've probably left out quite a bit of necessary information, so I'll update the question as needed.
What is the best way to undo the merge, and still be able to merge all changes in at a later date?
Thanks.
I just tried this doing it manually and when you attempt to merge after after having checked out an older version and then checking in the older version the file is still essentially flagged as already merged. I see the same exact problem when doing it without tfpt- pretty interesting.
So I took a look at the docs and it looks like what you are going to want to do is use /force. I am guessing if you do a tfpt rollback and then run tf merge it will work. If not, try manually rolling back and then running tf merge /force.
/force
Ignores the merge history and
merges the specified changes from the
source into the destination, even if
some or all these changes have been
merged before.
Hope that helps.

What am I doing wrong with SVN merging?

When SVN with merge tracking works, it's really nice, I love it. But it keeps getting twisted up. We are using TortoiseSVN. We continuously get the following message:
Error: Reintegrate can only be used if revisions 1234 through 2345 were previously merged from /Trunk to the reintegrate source, but this is not the case
For reference, this is the method we are using:
Create a Branch
Develop in the branch
Occasionally Merge a range of revisions from the Trunk to the Branch
When branch is stable, Reintegrate a branch from the branch to the trunk
Delete the branch
I Merge a range of revisions from the trunk to the branch (leaving the range blank, so it should be all revisions) just prior to the reintegrate operation, so the branch should be properly synced with the trunk.
Right now, the Trunk has multiple SVN merge tracking properties associated with it. Should it? Or should a Reintegrate not add any merge tracking info?
Is there something wrong with our process? This is making SVN unusable - 1 out of every 3 reintegrates forces me to dive in and hack at the merge tracking info.
This problem sometimes happens when a parial merge has been done from trunk to branch in the past. A partial merge is when you perform a merge on the whole tree but only commit part of it. This will give you files in your tree that have mergeinfo data that is out of sync with the rest of the tree.
The --reintegrate error message above should list the files that svn is having a problem with (at least it does in svn 1.6).
You can either:
Merge the problem files manually from trunk to branch, using the range from the error message. Note: you must subtract 1 from the start of the range, so the command you'd run would be:
cd <directory of problem file in branch working copy>
svn merge -r1233:2345 <url of file in trunk>
svn commit
or
If you're certain that the contents of the files in your branch are correct and you just want to mark the files as merged, you could use the --record-only flag to svn merge:
cd <directory of problem file in branch working copy>
svn merge --record-only -r1233:2345 <url of file in trunk>
svn commit
(I think you can use --record-only on the entire tree, but I haven't tried it and you'd have to be absolutely sure that there are no real merges that need to come from trunk)
Bunny hopping might be the solution.
Basically, instead of continuously merging trunk changes into a single branch (branches/foo, let's call it), when you want to pull those changes from trunk:
Copy trunk to a new branch (branches/foo2).
Merge in the changes from the old branch (merge branches/foo into branches/foo2).
Delete the old branch (delete branches/foo).
Your problem is that you're trying to use Reintegrate merge on a branch that has been 'corrupted' by having a 'half merge' already done on it. My advice is to ignore reintegrate and stick to plain on revision merging if this is your workflow.
However, the big reason you get errors is because SVN is performing some checks for you. In this case, if the merge has extra mergeinfo from individual files in there, then svn will throw a wobbly and prevent you from merging - mainly because this case can product errors that you might not notice. This is called a subtree merge in svn reintegrate terminology (read the Reintegrate to the Rescue section, particularly the controversial reintegrate check at the end).
You can stop recording mergeinfo when you perform your intermediary merges, or just leave the branch alone until its ready - then the merge will pick up changes made to trunk. I think you can also byass this check by only ever merging the entire trunk to branch, not individual files thus keeping mergeinfo safe for the final reintegrate at the end.
EDIT:
#randomusername: I think (never looked too closely) at moving is that it falls into the 'partial merge' trap. One cool feature of SVN is that you can do a sparse checkout - only get a partial copy of a tree. When you merge a partial tree in, SVN cannot say that the entire thing was merged as it obviously wasn't, so it records the mergeinfo slightly differently. This doesn't help with reintegrate as the reintegrate has to merge everything back to the trunk, and now it finds that some bits were modified without being merged, so it complains. A move appears kind of the same thing - a piece of the branched tree now appears differently in the mergeinfo than it expects. I would not bother with reintegrate, and stick with the normal revision range merge. Its a nice idea, but it trying to be too many things to too many users in too many different circumstances.
The full story for mergeinfo is here.
I suspect you're not following the merge instructions correctly:
"Now, use svn merge with the --reintegrate option to replicate your branch changes back into the trunk. You'll need a working copy of /trunk. You can get one by doing an svn checkout, dredging up an old trunk working copy from somewhere on your disk, or using svn switch (see the section called “Traversing Branches”). Your trunk working copy cannot have any local edits or contain a mixture of revisions (see the section called “Mixed-revision working copies”). While these are typically best practices for merging anyway, they are required when using the --reintegrate option.
Once you have a clean working copy of the trunk, you're ready to merge your branch back into it:"
I have few problems with merging.

"TF14083: The item {0} has a pending merge from the current merge operation" when merging TFS2008

I am getting this error when trying to merge TFS2008. There are no pending changes on either source or destination branches.
TF14083: The item {0} has a pending merge from the current merge operation, please resolve and check in the current merge and merge again to pick up this change.
There is a "Resolve Conflicts(x)" link at the top of the pending changes window that I missed.
Did you read this article?
One of the suggestions there is to try the operation in a new workspace.
Also, if you have renamed or deleted one or more branches/folders, there might be changes in your workspace you're not aware of. Is there anything (even outside the source and target) in your Pending Changes window?
Here's a work-around worked for me.
Short version: Merge all files that don't report TF14083 first and check in changes, then perform a remerge.
Long version:
We had no files in shelves or not checked in, but when trying to perform a merge from one branch to another I got the error message TF14083: The item '' has a pending merge from the current merge operation, please resolve and check in the current merge and merge again to pick up this change.
My workaround was to merge all other files except those reported with a TF14083 error. Check in that merge, then perform a new merge from and to the same branches as previously, and now TFS picked up the changes in those files reported with TF14083 in the previous merge operation and merged them with no warnings or errors.
Go figure!