=head1 NAME dgit - tutorial for package maintainers, using a workflow centered around git-merge(1) =head1 INTRODUCTION This document describes elements of a workflow for maintaining a non-native Debian package using B. The workflow makes the following opinionated assumptions: =over 4 =item Git histories should be the non-linear histories produced by git-merge(1), preserving all information about divergent development that was later brought together. =item Maintaining convenient and powerful git workflows takes priority over the usefulness of the raw Debian source package. The Debian archive is thought of as an output format. For example, we don't spend time curating a series of quilt patches. However, in straightforward cases, the information such a series would contain is readily available from B. =item It is more important to have the Debian package's git history be a descendent of upstream's git history than to use exactly the orig.tar that upstream makes available for download. =back This workflow is less suitable for some packages. When the Debian delta contains multiple pieces which interact, or which you aren't going to be able to upstream soon, it might be preferable to maintain the delta as a rebasing patch series. For such a workflow see for example dgit-maint-debrebase(7) and dgit-maint-gbp(7). =head1 INITIAL DEBIANISATION This section explains how to start using this workflow with a new package. It should be skipped when converting an existing package to this workflow. =head2 When upstream tags releases in git Suppose that the latest stable upstream release is 1.2.2, and this has been tagged '1.2.2' by upstream. =over 4 % git clone -oupstream https://some.upstream/foo.git % cd foo % git verify-tag 1.2.2 % git reset --hard 1.2.2 % git branch --unset-upstream =back The final command detaches your master branch from the upstream remote, so that git doesn't try to push anything there, or merge unreleased upstream commits. If you want to maintain a copy of your packaging branch on B in addition to B, you can do something like this: =over 4 % git remote add -f origin git.debian.org:/git/collab-maint/foo.git % git push --follow-tags -u origin master =back Now go ahead and Debianise your package. Just make commits on the master branch, adding things in the I directory. If you need to patch the upstream source, just make commits that change files outside of the I directory. It is best to separate commits that touch I from commits that touch upstream source, so that the latter can be cherry-picked by upstream. Note that there is no need to maintain a separate 'upstream' branch, unless you also happen to be involved in upstream development. We work with upstream tags rather than any branches, except when forwarding patches (see FORWARDING PATCHES UPSTREAM, below). Finally, you need an orig tarball: =over 4 % git deborig =back See git-deborig(1) if this fails. This tarball is ephemeral and easily regenerated, so we don't commit it anywhere (e.g. with tools like pristine-tar(1)). =head3 Verifying upstream's tarball releases =over 4 It can be a good idea to compare upstream's released tarballs with the release tags, at least for the first upload of the package. If they are different, you might need to add some additional steps to your I, such as running autotools. A convenient way to perform this check is to import the tarball as described in the following section, using a different value for 'upstream-tag', and then use git-diff(1) to compare the imported tarball to the release tag. If they are the same, you can use upstream's tarball instead of running git-deborig(1). =back =head2 When upstream releases only tarballs We need a virtual upstream branch with virtual release tags. gbp-import-orig(1) can manage this for us. To begin =over 4 % mkdir foo % cd foo % git init =back Now create I: =over 4 [DEFAULT] upstream-branch = upstream debian-branch = master upstream-tag = %(version)s sign-tags = True pristine-tar = False pristine-tar-commit = False [import-orig] merge-mode = merge =back gbp-import-orig(1) requires a pre-existing upstream branch: =over 4 % git add debian/gbp.conf && git commit -m "create gbp.conf" % git checkout --orphan upstream % git rm -rf . % git commit --allow-empty -m "initial, empty branch for upstream source" % git checkout -f master =back Then we can import the upstream version: =over 4 % gbp import-orig --merge-mode=replace ../foo_1.2.2.orig.tar.xz =back Our upstream branch cannot be pushed to B, but since we will need it whenever we import a new upstream version, we must push it somewhere. The usual choice is B: =over 4 % git remote add -f origin git.debian.org:/git/collab-maint/foo.git % git push --follow-tags -u origin master upstream =back You are now ready to proceed as above, making commits to both the upstream source and the I directory. =head1 CONVERTING AN EXISTING PACKAGE This section explains how to convert an existing Debian package to this workflow. It should be skipped when debianising a new package. =head2 No existing git history =over 4 % dgit clone foo % cd foo % git remote add -f upstream https://some.upstream/foo.git =back =head2 Existing git history using another workflow First, if you don't already have the git history locally, clone it, and obtain the corresponding orig.tar from the archive: =over 4 % git clone git.debian.org:collab-maint/foo % cd foo % origtargz =back Now dump any existing patch queue: =over 4 % git rm -rf debian/patches % git commit -m "drop existing quilt patch queue" =back Then make new upstream tags available: =over 4 % git remote add -f upstream https://some.upstream/foo.git =back =for dgit-test dpkg-source-ignores begin Now you simply need to ensure that your git HEAD is dgit-compatible, i.e., it is exactly what you would get if you ran B and then unpacked the resultant source package. =for dgit-test dpkg-source-ignores end To achieve this, you might need to delete I. One way to have dgit check your progress is to run B. The first dgit push will require I<--overwrite>. If this is the first ever dgit push of the package, consider passing I<--deliberately-not-fast-forward> instead of I<--overwrite>. This avoids introducing a new origin commit into your git history. (This origin commit would represent the most recent non-dgit upload of the package, but this should already be represented in your git history.) =head1 SOURCE PACKAGE CONFIGURATION =head2 debian/source/options We set some source package options such that dgit can transparently handle the "dropping" and "refreshing" of changes to the upstream source: =over 4 single-debian-patch auto-commit =back You don't need to create this file if you are using the version 1.0 source package format. =head2 Sample text for debian/source/patch-header It is a good idea to explain how a user can obtain a breakdown of the changes to the upstream source: =over 4 The Debian packaging of foo is maintained in git, using the merging workflow described in dgit-maint-merge(7). There isn't a patch queue that can be represented as a quilt series. A detailed breakdown of the changes is available from their canonical representation - git commits in the packaging repository. For example, to see the changes made by the Debian maintainer in the first upload of upstream version 1.2.3, you could use: =over 4 % git clone https://git.dgit.debian.org/foo % cd foo % git log --oneline 1.2.3..debian/1.2.3-1 -- . ':!debian' =back (If you have dgit, use `dgit clone foo`, rather than plain `git clone`.) A single combined diff, containing all the changes, follows. =back If you are using the version 1.0 source package format, this text should be added to README.source instead. The version 1.0 source package format ignores debian/source/patch-header. If you're using the version 3.0 (quilt) source package format, you could add this text to README.source instead of debian/source/patch-header, but this might distract from more important information present in README.source. =head1 BUILDING AND UPLOADING Use B, B, B, and B as detailed in dgit(1). If any command fails, dgit will provide a carefully-worded error message explaining what you should do. If it's not clear, file a bug against dgit. Remember to pass I<--new> for the first upload. As an alternative to B and friends, you can use a tool like gitpkg(1). This works because like dgit, gitpkg(1) enforces that HEAD has exactly the contents of the source package. gitpkg(1) is highly configurable, and one dgit user reports using it to produce and test multiple source packages, from different branches corresponding to each of the current Debian suites. If you want to skip dgit's checks while iterating on a problem with the package build (for example, you don't want to commit your changes to git), you can just run dpkg-buildpackage(1) or debuild(1) instead. =head1 NEW UPSTREAM RELEASES =head2 Obtaining the release =head3 When upstream tags releases in git =over 4 % git remote update =back =head3 When upstream releases only tarballs You will need the I from "When upstream releases only tarballs", above. You will also need your upstream branch. Above, we pushed this to B. You will need to clone or fetch from there, instead of relying on B/B alone. Then, either =over 4 % gbp import-orig --no-merge ../foo_1.2.3.orig.tar.xz =back or if you have a working watch file =over 4 % gbp import-orig --no-merge --uscan =back =head2 Reviewing & merging the release It's a good idea to preview the merge of the new upstream release. First, just check for any new or deleted files that may need accounting for in your copyright file: =over 4 % git diff --stat master..1.2.3 -- . ':!debian' =back You can then review the full merge diff: =over 4 % git merge-tree `git merge-base master 1.2.3` master 1.2.3 | $PAGER =back Once you're satisfied with what will be merged, update your package: =over 4 % git merge 1.2.3 % dch -v1.2.3-1 New upstream release. % git add debian/changelog && git commit -m changelog =back If you obtained a tarball from upstream, you are ready to try a build. If you merged a git tag from upstream, you will first need to generate a tarball: =over 4 % git deborig =back =head1 HANDLING DFSG-NON-FREE MATERIAL =head2 When upstream tags releases in git We create a DFSG-clean tag to merge to master: =over 4 % git checkout -b pre-dfsg 1.2.3 % git rm evil.bin % git commit -m "upstream version 1.2.3 DFSG-cleaned" % git tag -s 1.2.3+dfsg % git checkout master % git branch -D pre-dfsg =back Before merging the new 1.2.3+dfsg tag to master, you should first determine whether it would be legally dangerous for the non-free material to be publicly accessible in the git history on B. If it would be dangerous, there is a big problem; in this case please consult your archive administrators (for Debian this is the dgit administrator dgit-owner@debian.org and the ftpmasters ftpmaster@ftp-master.debian.org). =head2 When upstream releases only tarballs The easiest way to handle this is to add a B field to I, and a B setting in I. See uscan(1). Alternatively, see the I<--filter> option detailed in gbp-import-orig(1). =head1 FORWARDING PATCHES UPSTREAM The basic steps are: =over 4 =item 1. Create a new branch based off upstream's master branch. =item 2. git-cherry-pick(1) commits from your master branch onto your new branch. =item 3. Push the branch somewhere and ask upstream to merge it, or use git-format-patch(1) or git-request-pull(1). =back For example (and it is only an example): =over 4 % # fork foo.git on GitHub % git remote add -f fork git@github.com:spwhitton/foo.git % git checkout -b fix-error upstream/master % git config branch.fix-error.pushRemote fork % git cherry-pick master^2 % git push % # submit pull request on GitHub =back Note that when you merge an upstream release containing your forwarded patches, git and dgit will transparently handle "dropping" the patches that have been forwarded, "retaining" the ones that haven't. =head1 INCORPORATING NMUS =over 4 % dgit pull =back Alternatively, you can apply the NMU diff to your repository. The next push will then require I<--overwrite>. =head1 SEE ALSO dgit(1), dgit(7) =head1 AUTHOR This tutorial was written and is maintained by Sean Whitton . It contains contributions from other dgit contributors too - see the dgit copyright file.