Git rebase changes from parent branch not coming

Question

I have 2 branches X and Y. X is parent of Y.

X have some feature-branches rebased into it for e.g X-F1, X-F2..

Y also have some feature-branches rebased into it.for e.g Y-F1, Y-F2..

All the feature-branches commits have been squashed on both X and Y branches

Now I want to rebase X onto Y

so i write command git rebase X while I am on branch Y

The issue is some changes from branch X are not coming after rebasing

I can see all the changes when I am on branch X but as you know after rebasing they are missing.

Answer 1

Now I want to rebase X onto Y

so i write command git rebase X while I am on branch Y

That will rebase Y onto X.

---

Let's investigate:

I have 2 branches X and Y. X is parent of Y.

Branches do not have parents, commits do. I assuming you meant "branch Y was branched off branch X at some point"

X have some feature-branches rebased into it for e.g X-F1, X-F2..

Y also have some feature-branches rebased into it.for e.g Y-F1, Y-F2..

All the feature-branches commits have been squashed on both X and Y branches

According to your description, your history graph could look something like this:

x1-x2-xf1-x3-xf2-x4-x5        < X
           \
            y1-y2-yf1-y3-yf2  < Y

Now, running git checkout Y && git rebase X (which can be done with a single command: git rebase X Y), will produce the following history:

x1-x2-xf1-x3-xf2-x4-x5                       < X
                     \
                      y1'-y2'-yf1'-y3'-yf2'  < Y

But you claimed

Now I want to rebase X onto Y

Which should be git rebase Y X (or the longer git checkout X && git rebase Y), resulting in the history:

x1-x2-xf1-x3                               < X
           \
            y1-y2-yf1-y3-yf2-xf2'-x4'-x5'  < Y

Rebase will automatically drop commits which it detects as being already applied or which would result in an empty change set.