[How to undo multiple changesets on main branch after mistakes?]

Sure!

At first I searched for "Plastic SCM delete changeset" and similar things like "undo changeset" and quickly found this page: http://blog.plasticscm.com/2014/07/how-to-undo-merge.html

There I learned about the subtractive merge feature, but it did not mention that I could apply it to a changeset interval on the blog.

So, I continued the search for "Plastic SCM subtractive merge" and found this page via google: https://www.plasticscm.com/documentation/advanced-version-control-guide#subtractive-merge

I read over the entire page and then re-read the section "Subtractive Merge" a few times. It explained nicely how to remove a single changeset, however I did not initially understand that I could apply this to an interval. Now, that I know about the feature it also seems obvious, because the previous section is "Interval Merge". However, as a beginner, the term "interval merge" did not sound like something I would need and I failed to make the connection that the interval can probably be used for most other operations. Maybe it could be made more clear with a small cross reference such as "to apply subtractive merge to a range of changesets see the section about interval merge" or something like that.

I did not find any other pages about these features.

[How to undo multiple changesets on main branch after mistakes?]

After digging around on the forum for a bit, I found the following thread which seems to contain my answer: 

 

There, manu explains how to use "Subtractive merge from this changeset interval", which does what I need. I read about subtractive merge on the blog and on one of the documentation pages, but there the interval option was not mentioned, so I didn't know about it.

After testing it on a dummy repository, I used it on our real repo and it worked great!

PS: Maybe I'm failing at googling and reading the docs, but I still can't find the official documentation where it says that subtractive merge works on an interval, maybe that's something to add.

[How to undo multiple changesets on main branch after mistakes?]

Shortly before our last milestone delivery, we basically screwed up our project and committed it multiple times to the main branch. Normally, we would have used a task-branch and then would have simply abandoned it, but in this case, due to last-minute stress, our developers thought they could all fix it on main, so we ended up with this:

Everything marked in red should be discarded (the entire changesets only contain follow-up on an earlier mistake). Due to panic-mode, we branched-off the earlier changeset where everything was still working and continued with a few working changes on the Milestone 02 branch. This milestone branch I would like to merge to main but without the changesets marked in red. I would also like to include the changeset on main right after the split into the other branch.

What is the cleanest way of fixing this? I know about subtractive merge for a single changeset, but wouldn't I have to do it 6 times to remove all the red changesets here?