Merging is the process of taking all Ubuntu changes made on top of one Debian version of a package, and re-doing them on top of a new Debian version of the package.
There is a more detailed workflow here. This guide is intended to cover the majority of use cases.
You can get a list of packages that have been changed in Debian, but not merged into Ubuntu, here: http://reqorts.qa.ubuntu.com/reports/ubuntu-server/merges.html
We do merges using git ubuntu. As such, the process follows in many ways that of a git rebase, where commits from one point are replayed on top of another point:
--- something 1.2 ----------------------------- something 1.3
\ \
-- Ubuntu changes a, b, c -- 1.2ubuntu1 -- Ubuntu changes a, b, c -- 1.3ubuntu1
At a more detailed level, there are other subtasks to be done, such as:
- Splitting out large "omnibus" style commits into smaller logical units, one commit per logical unit.
- Harmonizing
debian/changelogcommits into two commits: a changelog merge and a reconstruction.
With this process, we keep the Ubuntu version of a package cleanly applied to the end of the latest Debian version, and make it easy to drop changes as they become redundant.
- Preliminary Steps
- The Merge Process
- Upload a PPA
- Test the New Build
- Submit Merge Proposal
- Follow Migration
First, you'll need to check that a newer version is even available from Debian. For this, we can use the rmadison tool:
rmadison [package]
rmadison -u debian [package]
Example:
$ rmadison at
at | 3.1.13-1ubuntu1 | precise | source, amd64, armel, armhf, i386, powerpc
at | 3.1.14-1ubuntu1 | trusty | source, amd64, arm64, armhf, i386, powerpc, ppc64el
at | 3.1.18-2ubuntu1 | xenial | source, amd64, arm64, armhf, i386, powerpc, ppc64el, s390x
at | 3.1.20-3.1ubuntu2 | bionic | source, amd64, arm64, armhf, i386, ppc64el, s390x
at | 3.1.20-3.1ubuntu2 | cosmic | source, amd64, arm64, armhf, i386, ppc64el, s390x
at | 3.1.20-3.1ubuntu2 | disco | source, amd64, arm64, armhf, i386, ppc64el, s390x
$ rmadison -u debian at
at | 3.1.13-2+deb7u1 | oldoldstable | source, amd64, armel, armhf, i386, ia64, kfreebsd-amd64, kfreebsd-i386, mips, mipsel, powerpc, s390, s390x, sparc
at | 3.1.16-1 | oldstable | source, amd64, arm64, armel, armhf, i386, mips, mipsel, powerpc, ppc64el, s390x
at | 3.1.16-1 | oldstable-kfreebsd | source, kfreebsd-amd64, kfreebsd-i386
at | 3.1.20-3 | stable | source, amd64, arm64, armel, armhf, i386, mips, mips64el, mipsel, ppc64el, s390x
at | 3.1.23-1 | testing | source, amd64, arm64, armel, armhf, i386, mips, mips64el, mipsel, ppc64el, s390x
at | 3.1.23-1 | unstable | source, amd64, arm64, armel, armhf, hurd-i386, i386, kfreebsd-amd64, kfreebsd-i386, mips, mips64el, mipsel, ppc64el, s390x
at | 3.1.23-1 | unstable-debug | source
You'll be merging from debian unstable, which in this example is 3.1.23-1.
Check for any low hanging fruit in the debian or ubuntu bug list that can be wrapped into this merge.
https://bugs.launchpad.net/ubuntu/+source/[package]
https://tracker.debian.org/pkg/[package]
If there are bugs you'd like to fix, make a new SRU style commit at the end of the merge process and put them together in the same merge proposal.
Search for an existing merge request bug entry in launchpad, and if you don't find one, go to the package's launchpad page (https://bugs.launchpad.net/ubuntu/+source/some-package) and create a new bug report, requesting a merge.
Example:
URL: https://bugs.launchpad.net/ubuntu/+source/at/+filebug
Summary: "Please merge 3.1.23-1 into disco"
Description: "tracking bug"
result: https://bugs.launchpad.net/ubuntu/+source/at/+bug/1802914
Save the bug report number, because you'll be using it throughout the merge process.
git ubuntu clone <package> [<package>-gu]
Example:
$ git ubuntu clone at at-gu
It's a good idea to append some git ubuntu specific label (like -gu) to distinguish it from clones of Debian or upstream git repositories (which tend to want to clone as the same name).
From within the git source tree:
git ubuntu merge start ubuntu/devel --bug [bug number]
For example:
$ git ubuntu merge start ubuntu/devel --bug 1802914
This will generate the following tags for you:
| Tag | Source |
|---|---|
| old/ubuntu | ubuntu/devel |
| old/debian | last import tag prior to old/ubuntu without ubuntu suffix in version |
| new/debian | debian/sid |
The tags themselves will be name-spaced to the current bug in the format lp12345678. Thus, for example, your tags may look like:
lp1802914/old/ubuntulp1802914/old/debianlp1802914/new/debian
If git ubuntu merge start fails, do it manually
Use the merge tracking bug and the ubuntu version it's going into (for example disco).
$ git checkout -b merge-lp1802914-disco
If there's no merge bug than the Debian package version you're merging onto can be used (for example merge-3.1.23-1-disco)
In this phase, you split out old-style commits that lumped multiple changes together.
$ git log --oneline
2af0cb7 (HEAD -> merge-3.1.20-6-disco, tag: lp1802914/reconstruct/3.1.20-3.1ubuntu2, tag: lp1802914/split/3.1.20-3.1ubuntu2) import patches-unapplied version 3.1.20-3.1ubuntu2 to ubuntu/disco-proposed
2a71755 (tag: pkg/import/3.1.20-5) Import patches-unapplied version 3.1.20-5 to debian/sid
9c3cf29 (tag: pkg/import/3.1.20-3.1) Import patches-unapplied version 3.1.20-3.1 to debian/sid
...
Get all commit hashes since old/debian, and:
git show [hash] | diffstat
Example:
$ git show 2af0cb7 | diffstat
changelog | 6 ++++++
control | 4 ++--
2 files changed, 8 insertions(+), 2 deletions(-)
Here's another typical example, for the nspr package:
$ git show d7ebe661 | diffstat
changelog | 501 ++++++++++++++++++++++++++++
control | 3
patches/fix_test_errcodes_for_runpath.patch | 11
patches/series | 1
rules | 5
5 files changed, 520 insertions(+), 1 deletion(-)
Any time you see changelog and any other file(s) changing in a single commit, it's guaranteed that you'll need to split it; changelog should only ever change in it own commit. You should still look over commits to make sure, but this is a dead giveaway.
Another giveaway would be a commit named Import patches-unapplied version 1.2.3ubuntu4 to ubuntu/cosmic-proposed, where it's applying from an ubuntu source rather than a debian one (in this case ubuntu4).
If there are no commits to split, simply add the split tag and move on.
The next step is to separate the changes into logical units. For the at package, this is trivial: just put the changelog change in one commit, and the control change in the other.
The second example, for nspr, is more instructive. Here we have 5 files changed, that need split out:
- All changelog changes go to one commit called
changelog. - Update maintainer (in debian/control) goes to one commit called
update maintainers. - All other logically separable commits go into individual commits.
Look in debian/changelog:
nspr (2:4.18-1ubuntu1) bionic; urgency=medium
* Resynchronize with Debian, remaining changes
- rules: Enable Thumb2 build on armel, armhf.
- d/p/fix_test_errcodes_for_runpath.patch: Fix testcases to handle
zesty linker default changing to --enable-new-dtags for -rpath.
There are two logical changes, which we'll need to separate. Look at the changes in individual files to see which file changes should be logically grouped together.
Example:
$ git show d7ebe661 -- debian/rules
In this case, we have the following file changes to separate into logical units:
| File(s) | Logical Unit |
|---|---|
debian/rules |
Enable Thumb2 build on armel, armhf. |
debian/patches/* |
Fix testcases to handle zesty linker default changing to --enable-new-dtags for -rpath. |
debian/control |
Change maintainer |
debian/changelog |
Changelog |
Start a rebase at old/debian, and then reset to HEAD^ to bring back the changes as uncommitted changes.
- Start a rebase:
git rebase -i lp1803562/old/debian - Change the commit(s) you're going to split from
picktoedit. - git reset to get your changes back:
git reset HEAD^
Next, add the commits:
Logical Unit:
$ git add debian/patches/*
$ git commit
Commit Message:
* d/p/fix_test_errcodes_for_runpath.patch: Fix testcases to handle
zesty linker default changing to --enable-new-dtags for -rpath.
Logical Unit:
$ git add debian/rules
$ git commit
Commit Message:
* d/rules: Enable Thumb2 build on armel, armhf.
Maintainers:
$ git commit -m "update maintainers" debian/control
Changelog:
$ git commit -m changelog debian/changelog
Finally, complete the rebase:
$ git rebase --continue
Note: Do this even if there were no commits to split.
$ git ubuntu tag --split --bug 1803562
In this phase, we make a clean, "logical" view of the history. This history is cleaned up (but has the same delta), and only contains the actual changes that affect the package's behavior.
Start a rebase from old/debian:
$ git rebase -i lp1803562/old/debian
Now we do some cleaning:
- Delete imports, etc
- Delete changelog, maintainer
- Possibly rearrange commits if it makes logical sense
You should also squash these kinds of commits together:
- Changes and reversions of those changes, since they resolve to a no-op.
- Multiple changes to the same patch file, since they should be a logical unit.
To squash a commit, move its line underneath the one you want it to become part of, and then change it from pick to fixup.
At the end of the squash and clean phase, the only delta you should see from the split tag is:
$ git diff lp1803562/split/2%4.18-1ubuntu1 |diffstat
changelog | 762 --------------------------------------------------------------
control | 3
2 files changed, 1 insertion(+), 764 deletions(-)
Only changelog and control were changed, which is what we want.
$ git ubuntu tag --logical --bug 1803562
This may fail with an error like: ERROR:HEAD is not a defined object in this git repository., in which case do it manually
$ git rebase -i --onto lp1803562/new/debian lp1803562/old/debian
If a conflict occurs, you must resolve it. We do so by modifying the conflicting commit during the rebase.
An example, merging logwatch 7.5.0-1:
$ git rebase -i --onto lp1810928/new/debian lp1810928/old/debian
...
CONFLICT (content): Merge conflict in debian/control
error: could not apply c0efd06... - Drop libsys-cpu-perl and libsys-meminfo-perl from Recommends to
...
Take a look at the conflict in debian/control:
<<<<<<< HEAD
Recommends: libdate-manip-perl, libsys-cpu-perl, libsys-meminfo-perl
=======
Recommends: libdate-manip-perl
Suggests: fortune-mod, libsys-cpu-perl, libsys-meminfo-perl
>>>>>>> c0efd06... - Drop libsys-cpu-perl and libsys-meminfo-perl from Recommends to
Upstream removed fortune-mod, and deleted the entire line since it was no longer needed. Resolve it to:
Recommends: libdate-manip-perl
Suggests: libsys-cpu-perl, libsys-meminfo-perl
Continue with the rebase:
$ git add debian/control
$ git rebase --continue
If a commit becomes empty, it's because the change has already been applied upstream:
The previous cherry-pick is now empty, possibly due to conflict resolution.
In such a case, the commit can be dropped.
$ git rebase --abort
$ git rebase -i lp1803296/old/debian
Keep a copy of the unneeded commit's commit message, then delete it in the rebase.
$ quilt push -a --fuzz=0
Quilt can fail at this point if the file being patched has changed significantly upstream. The most common reason is that the issue the patch addresses has since been fixed upstream.
For example:
$ quilt push -a --fuzz=0
...
Applying patch ssh-ignore-disconnected.patch
patching file scripts/services/sshd
Hunk #1 FAILED at 297.
1 out of 1 hunk FAILED -- rejects in file scripts/services/sshd
Patch ssh-ignore-disconnected.patch does not apply (enforce with -f)
If this patch fails because the changes in ssh-ignore-disconnected.patch are already applied upstream, you must remove this patch.
$ git log --oneline
1aed93f (HEAD -> ubuntu/devel) * d/p/ssh-ignore-disconnected.patch: [sshd] ignore disconnected from user USER (LP: 1644057)
7d9d752 - Drop libsys-cpu-perl and libsys-meminfo-perl from Recommends to Suggests as they are in universe.
Removing 1aed93f will remove the patch.
- Save the commit message from
1aed93ffor later including in theDropped Changessection of the new changelog entry. git rebase -i 7d9d752and delete commit1aed93f.
$ quilt pop -a
$ git ubuntu merge finish ubuntu/devel --bug 1803296
- If this fails, do it manually
Git ubuntu attempts to put together a changelog entry, but it will likely have problems. Fix it up to make sure it follows the standards. See Committing your Changes for information about what it should look like.
If you dropped any changes (due to upstream fixes), you must note them in the changelog entry:
* Dropped Changes:
- Foo: change to bar
[Fixed in 1.2.3-4]
$ git commit debian/changelog -m changelog
Now you must rebase and squash the changelog changes into the "reconstruct-changelog" commit. Do a rebase with the new/debian tag:
$ git rebase -i lp1810928/new/debian
Change the order from:
pick e431327 merge-changelogs
pick cf3b93a reconstruct-changelog
pick 21cea1a update-maintainer
pick 08c2f4d changelog
to:
pick e431327 merge-changelogs
pick cf3b93a reconstruct-changelog
f 08c2f4d changelog
pick 21cea1a update-maintainer
Notice above that you must also change the changelog rebase command to fixup (or f).
Ubuntu doesn't know about the new tarball yet, so we must create it.
$ git ubuntu export-orig
- If this fails, do it manually
$ dpkg-buildpackage -S -nc -d -sa -v3.1.20-3.1ubuntu2
The switches are:
- -S = build source only
- -nc = no clean
- -d = ?
- -sa = include orig tarball (required on a merge)
- -vXYZ = include changelog since XYZ
Changes should be from the last ubuntu version
$ lintian --pedantic --display-info --verbose --info --profile ubuntu ../at_3.1.23-1ubuntu1.dsc
Now that the package is tested and builds successfully, it's time to push it to your launchpad repository.
The easiest way is to run it like this:
git push your-lp-username
You'll get an error message and a suggestion for how to set upstream. For example:
$ git push kstenerud
fatal: The current branch merge-lp1802914-disco has no upstream branch.
To push the current branch and set the remote as upstream, use
git push --set-upstream kstenerud merge-lp1802914-disco
Run the suggested command to push to your repository.
$ git push kstenerud $(git tag |grep 1802914 | xargs)
To ssh://git.launchpad.net/~kstenerud/ubuntu/+source/at
* [new tag] lp1802914/split/3.1.20-3.1ubuntu2 -> lp1802914/split/3.1.20-3.1ubuntu2
* [new tag] lp1802914/logical/3.1.20-3.1ubuntu2 -> lp1802914/logical/3.1.20-3.1ubuntu2
* [new tag] lp1802914/new/debian -> lp1802914/new/debian
* [new tag] lp1802914/old/debian -> lp1802914/old/debian
* [new tag] lp1802914/old/ubuntu -> lp1802914/old/ubuntu
* [new tag] lp1802914/reconstruct/3.1.20-3.1ubuntu2 -> lp1802914/reconstruct/3.1.20-3.1ubuntu2
You'll need to have a PPA for reviewers to test.
https://launchpad.net/~kstenerud/+activate-ppa
Give it a name that identifies the ubuntu version, package name, and bug number, such as at-merge-lp1802914
IMPORTANT: Be sure to enable all architectures to check that it builds (click on Change details in the top right corner of the newly created PPA page).
$ dput ppa:kstenerud/at-merge-lp1802914 ../at_3.1.23-1ubuntu1_source.changes
Check the PPA page to see when packages are finished building: https://launchpad.net/~kstenerud/+archive/ubuntu/at-merge-lp1802914
Also, look at the package contents to make sure they have actually been published: https://launchpad.net/~kstenerud/+archive/ubuntu/at-merge-lp1802914/+packages
Test the following:
1. Package Tests
2. Upgrading from the previous version
3. Installing the latest where nothing was installed before
4. Other smoke tests
Example:
Note: Disco is not yet available at the time of writing, so we use cosmic.
$ lxc launch ubuntu-daily:cosmic tester && lxc exec tester bash
$ apt update && apt dist-upgrade -y && apt install -y at
The test:
echo "echo xyz >test.txt" |at now + 1 minute && sleep 1m && cat test.txt && rm test.txt
Upgrade:
$ add-apt-repository -y ppa:kstenerud/at-merge-lp1802914
Note: Disco is not yet available at the time of writing, so we must modify the source list entry:
$ vi /etc/apt/sources.list.d/kstenerud-ubuntu-at-merge-lp1802914-cosmic.list
* change cosmic to disco
$ apt update && apt dist-upgrade -y
Test the upgraded version:
$ echo "echo abc >test.txt" | at now + 1 minute && sleep 1m && cat test.txt && rm test.txt
$ lxc launch ubuntu-daily:cosmic tester && lxc exec tester bash
$ add-apt-repository -y ppa:kstenerud/at-merge-lp1802914
$ apt update && apt dist-upgrade -y && apt install at
$ echo "echo abc >test.txt" | at now + 1 minute && sleep 1m && cat test.txt && rm test.txt
- Try running various basic commands.
- Try running regression tests: https://git.launchpad.net/qa-regression-testing
NOTE: Git branch with % in name doesn't work. Use something like _
$ git ubuntu submit --reviewer canonical-server-packageset-reviewers --target-branch debian/sid
Your merge proposal is now available at: https://code.launchpad.net/~kstenerud/ubuntu/+source/at/+git/at/+merge/358655
If it looks OK, please move it to the 'Needs Review' state.
- If this fails, do it manually
- Link the PPA
- add any other info that will help reviewer to mp as a comment.
Example:
PPA: https://launchpad.net/~kstenerud/+archive/ubuntu/at-merge-lp1802914
Basic test:
$ echo "echo abc >test.txt" | at now + 1 minute && sleep 1m && cat test.txt && rm test.txt
Package tests:
This package contains no tests.
Change the MP status from "work in progress" to "needs review"
Once the merge proposal goes through, you must follow the package to make sure it gets to its destination.
The results from the latest package tests will be published for each ubuntu release.
For example: http://autopkgtest.ubuntu.com/packages/o/openssh/cosmic/amd64
The status of all packages will be available from http://people.canonical.com/~ubuntu-archive/proposed-migration or one of its subdirectories. The top level directory is for the current dev release. Previous releases are in subdirectories.
Create a branch to do the merge work in:
$ git checkout -b merge-lp1802914-disco
| Tag | Source |
|---|---|
| old/ubuntu | ubuntu/disco-devel |
| old/debian | last import tag prior to old/ubuntu without ubuntu suffix in version |
| new/debian | debian/sid |
per: https://www.debian.org/releases/ "debian/sid" always matches to debian unstable.
You can find the last import tag using git log | grep "tag: pkg/import" | grep -v ubuntu | head -1:
...
commit 9c3cf29c05c3fddd7359e71c978ff9a9a76e4404 (tag: pkg/import/3.1.20-3.1)
So, we create the following tags:
$ git tag lp1802914/old/ubuntu pkg/ubuntu/disco-devel
$ git tag lp1802914/old/debian 9c3cf29c05c3fddd7359e71c978ff9a9a76e4404
$ git tag lp1802914/new/debian pkg/debian/sid
$ git rebase -i lp1802914/old/debian
If the package hasn't been updated since the git repository structure has changed, it will grab all changes throughout time rather than since the last debian version. Simply delete the older lines from the interactive rebase
In this case, up to, and including import of 3.1.20-3.1
$ git ubuntu tag --reconstruct --bug 1802914
Next step: Split Commits
Use the version number of the last ubuntu change. So if there are 3.1.20-3.1ubuntu1 and 3.1.20-3.1ubuntu2, use 3.1.20-3.1ubuntu2.
$ git tag -a -m "Logical delta of 3.1.20-3.1ubuntu2" lp1802914/logical/3.1.20-3.1ubuntu2
Note: Certain characters aren't allowed in git. For example, : should be replaced with %.
Next step: Rebase onto new debian
Merge changelogs of old ubuntu and new debian:
$ git show lp1802914/new/debian:debian/changelog >/tmp/debnew.txt
$ git show lp1802914/old/ubuntu:debian/changelog >/tmp/ubuntuold.txt
$ merge-changelog /tmp/debnew.txt /tmp/ubuntuold.txt >debian/changelog
$ git commit -m "Merge changelogs" debian/changelog
Create new changelog entry for the merge:
$ dch -i
Which creates for example:
at (3.1.23-1ubuntu1) disco; urgency=medium
* Merge with Debian unstable (LP: #1802914). Remaining changes:
- Suggest an MTA rather than Recommending one.
-- Karl Stenerud <[email protected]> Mon, 12 Nov 2018 18:11:53 +0100
Commit the changelog:
$ git commit -m "changelog: Merge of 3.1.23-1" debian/changelog
Update maintainer:
$ update-maintainer
$ git commit -m "Update maintainer" debian/control
Next step: Fix the Changelog
$ git checkout -b pkg/importer/debian/pristine-tar
$ pristine-tar checkout at_3.1.23.orig.tar.gz
$ git checkout merge-3.1.23-1-disco
$ git checkout merge-lp1802914-disco
$ cd /tmp
$ pull-debian-source at
$ mv at_3.1.23.orig.tar.gz ~/work/packages/ubuntu/
$ cd -
Next step: Check the source for errors
$ git push kstenerud merge-lp1802914-disco
Then, create a MP manually in launchpad, and save the URL.
Next step: Update the merge proposal