Question

I’ve read the RebaseProject page and tried a non-trivial example
(not rebasing a complete branch). It’s similar to the case rebase D on
I of the scenario B.

Here’s the situation before the rebase:

default : 0 ----- 2
            \
feature :     1 ----- 3

Now I’d like to rebase 3 on 2, giving:

default : 0 ----- 2 ----- 3
            \
feature :     1

Unfortunately the exact commands aren’t given in the RebaseProject
page, but from my understanding of the usage synopsis it should be:

hg rebase --source 3 --dest 2

But somehow my understanding must be flawed, because I get a rebase combined with a merge:

default : 0 ----- 2 ----- 3
            \           /
feature :     1 -------

Why is that?

Commands to reproduce the scenario:

hg init
touch a
hg add a
hg commit -m "added a"
hg branch feature
touch b
hg add b
hg commit -m "added b on feature"
hg up -C default
touch c
hg add c
hg commit -m "added c on default"
hg up -C feature
echo "feature" >> a
hg commit -m "changed a on feature"
hg rebase --source 3 --dest 2

Answer 1

Your scenario looks very similar to part rebase G onto I of scenario B of the Rebase Project Scenarios:

Scenario B
…

…

rebase G onto I

In your scenario, D == 1, I == 2 and G == 3. After rebasing, 3 maintains its relationship to 1 just like G' maintained its relationship to D. This is because D is not an ancestor of I and:

Note: Rebase drops a parent relationship only if the parent is an ancestor of target.

You really want to remove that relationship, then, according to the docs, you need a development version to get the --detach option:

Using a development version is available the new –detach option that drops this relationship.