3 dgit - tutorial for package maintainers, using a workflow centered around git-debrebase(1)
7 This document describes elements of a workflow for maintaining a
8 non-native Debian package using B<dgit>. We maintain the Debian delta
9 as a series of git commits on our master branch. We use
10 git-debrebase(1) to shuffle our branch such that this series of git
11 commits appears at the end of the branch. All the public git history
12 is fast-forwarding, i.e., we do not rewrite and force-push.
14 Some advantages of this workflow:
20 Manipulate the delta queue using the full power of git-rebase(1),
21 instead of relying on quilt(1), and without having to switch back and
22 forth between patches-applied and patches-unapplied branches when
23 committing changes and trying to build, as with gbp-pq(1).
27 If you are using 3.0 (quilt), provide your delta queue as a properly
28 separated series of quilt patches in the source package that you
29 upload to the archive (unlike with dgit-maint-merge(7)).
33 Avoid the git tree being dirtied by the application or unapplication
34 of patches, as they are always applied.
38 Benefit from dgit's safety catches. In particular, ensure that your
39 upload always matches exactly your git HEAD.
43 Provide your full git history in a standard format on B<dgit-repos>,
44 where it can benefit downstream dgit users, such as people using dgit
45 to do an NMU (see dgit-nmu-simple(7) and dgit-user(7)).
49 Minimise the amount you need to know about 3.0 (quilt) in order to
50 maintain Debian source packages which use that format.
54 This workflow is appropriate for packages where the Debian delta
55 contains multiple pieces which interact, or which you don't expect to
56 be able to upstream soon. For packages with simple and/or short-lived
57 Debian deltas, use of git-debrebase(1) introduces unneeded complexity.
58 For such packages, consider the workflow described in
61 =head1 INITIAL DEBIANISATION
63 This section explains how to start using this workflow with a new
64 package. It should be skipped when converting an existing package to
67 =head2 When upstream tags releases in git
69 Suppose that the latest stable upstream release is 1.2.2, and this has
70 been tagged '1.2.2' by upstream.
74 % git clone -oupstream https://some.upstream/foo.git
76 % git verify-tag 1.2.2
77 % git reset --hard 1.2.2
78 % git branch --unset-upstream
82 The final command detaches your master branch from the upstream
83 remote, so that git doesn't try to push anything there, or merge
84 unreleased upstream commits. To maintain a copy of your packaging
85 branch on B<salsa.debian.org> in addition to B<dgit-repos>, you can do
90 % git remote add -f origin salsa.debian.org:Debian/foo.git
91 % git push --follow-tags -u origin master
95 Now go ahead and Debianise your package. Make commits on the master
96 branch, adding things in the I<debian/> directory, or patching the
97 upstream source. For technical reasons, B<it is essential that your
98 first commit introduces the debian/ directory containing at least one
99 file, and does nothing else.> In other words, make a commit
100 introducing I<debian/> before patching the upstream source.
102 Finally, you need an orig tarball:
110 See git-deborig(1) if this fails.
112 This tarball is ephemeral and easily regenerated, so we don't commit
113 it anywhere (e.g. with tools like pristine-tar(1)).
115 =head3 Comparing upstream's tarball releases
119 The above assumes that you know how to build the package from git and
120 that doing so is straightforward.
122 If, as a user of the upstream source, you usually build from upstream
123 tarball releases, rather than upstream git tags, you will sometimes
124 find that the git tree doesn't contain everything that is in the
127 Additional build steps may be needed. For example, you may need your
128 I<debian/rules> to run autotools.
130 You can compare the upstream tarball release, and upstream git tag,
131 within git, by importing the tarball into git as described in the
132 next section, using a different value for 'upstream-tag', and then
133 using git-diff(1) to compare the imported tarball to the release tag.
137 =head3 Using untagged upstream commits
141 Sometimes upstream does not tag their releases, or you want to package
142 an unreleased git snapshot. In such a case you can create your own
143 upstream release tag, of the form B<upstream/>I<ver>, where I<ver> is
144 the upstream version you plan to put in I<debian/changelog>. The
145 B<upstream/> prefix ensures that your tag will not clash with any tags
146 upstream later creates.
148 For example, suppose that the latest upstream release is 1.2.2 and you
149 want to package git commit ab34c21 which was made on 2013-12-11. A
150 common convention is to use the upstream version number
151 1.2.2+git20131211.ab34c21 and so you could use
155 % git tag -s upstream/1.2.2+git20131211.ab34c21 ab34c21
159 to obtain a release tag, and then proceed as above.
163 =head2 When upstream releases only tarballs
165 Because we want to work in git, we need a virtual upstream branch with
166 virtual release tags. gbp-import-orig(1) can manage this for us. To
174 % git checkout -b upstream
176 --upstream-branch=upstream --debian-branch=master \
177 --upstream-tag='upstream/%(version)s' \
178 --sign-tags --no-pristine-tar \
179 ../foo_1.2.2.orig.tar.xz
180 % git branch -f upstream
184 This should leave you on the master branch. Next, our upstream branch
185 cannot be pushed to B<dgit-repos>, but since we will need it whenever
186 we import a new upstream version, we must push it somewhere. The
187 usual choice is B<salsa.debian.org>:
191 % git remote add -f origin salsa.debian.org:Debian/foo.git
192 % git push --follow-tags -u origin master upstream
196 You are now ready to proceed as above, making commits to the
197 I<debian/> directory and to the upstream source. As above, for
198 technical reasons, B<it is essential that your first commit introduces
199 the debian/ directory containing at least one file, and does nothing
200 else.> In other words, make a commit introducing I<debian/> before
201 patching the upstream source.
203 A convenient way to ensure this requirement is satisfied is to start
204 by creating I<debian/gbp.conf>:
209 upstream-branch = upstream
210 debian-branch = master
211 upstream-tag = upstream/%(version)s
215 pristine-tar-commit = False
226 % git add debian/gbp.conf && git commit -m "create gbp.conf"
230 Note that we couldn't create I<debian/gbp.conf> before now for the
231 same technical reasons which require our first commit to introduce
232 I<debian/> without patching the upstream source. That's why we had to
233 pass a lot of options to our first call to gbp-import-orig(1).
235 =head1 CONVERTING AN EXISTING PACKAGE
237 This section explains how to convert an existing Debian package to
238 this workflow. It should be skipped when debianising a new package.
240 If you have an existing git history that you have pushed to an
241 ordinary git server like B<salsa.debian.org>, we start with that. If
242 you don't already have it locally, you'll need to clone it, and obtain
243 the corresponding orig.tar from the archive:
247 % git clone salsa.debian.org:Debian/foo
249 % dgit setup-new-tree
254 If you don't have any existing git history, or you have history only
255 on the special B<dgit-repos> server, we start with B<dgit clone>:
264 Then we make new upstream tags available:
268 % git remote add -f upstream https://some.upstream/foo.git
272 We now use a B<git debrebase convert-from-*> command to convert your
273 existing history to the git-debrebase(5) data model. Which command
274 you should use depends on some facts about your repository:
278 =item (A) There is no delta queue.
280 If there do not exist any Debian patches, use
284 % git debrebase convert-from-gbp
288 =item (B) There is a delta queue, and patches are unapplied.
290 This is the standard git-buildpackage(1) workflow: there are Debian
291 patches, but the upstream source is committed to git without those
296 % git debrebase convert-from-gbp
300 If you were not previously using dgit to upload your package (i.e. you
301 were not using the workflow described in dgit-maint-gbp(7)), and you
302 happen to have run B<dgit fetch sid> in this clone of the repository,
303 you will need to pass I<--fdiverged> to this command.
305 =item (C) There is a delta queue, and patches are applied.
311 % git debrebase convert-from-dgit-view
317 Finally, you need to ensure that your git HEAD is dgit-compatible,
318 i.e., it is exactly what you would get if you deleted .git, invoked
319 B<dpkg-buildpackage -S>, and then unpacked the resultant source
322 To achieve this, you might need to delete
323 I<debian/source/local-options>. One way to have dgit check your
324 progress is to run B<dgit build-source>.
326 =head1 GIT CONFIGURATION
328 git-debrebase(1) does not yet support using B<git merge> to merge
329 divergent branches of development (see "OTHER MERGES" in
330 git-debrebase(5)). You should configure git such that B<git pull>
331 does not try to merge:
335 % git config --local pull.rebase true
339 Now when you pull work from other Debian contributors, git will rebase
340 your work on top of theirs.
342 If you use this clone for upstream development in addition to
343 Debian packaging work, you may not want to set this global setting.
344 Instead, see the B<branch.autoSetupRebase> and
345 B<branch.E<lt>nameE<gt>.rebase> settings in git-config(5).
347 =head1 IMPORTING NEW UPSTREAM RELEASES
349 There are two steps: obtaining git refs that correspond to the new
350 release, and importing that release using git-debrebase(1).
352 =head2 Obtaining the release
354 =head3 When upstream tags releases in git
358 % git fetch --tags upstream
362 If you want to package an untagged upstream commit (because upstream
363 does not tag releases or because you want to package an upstream
364 development snapshot), see "Using untagged upstream commits" above.
366 =head3 When upstream releases only tarballs
368 You will need the I<debian/gbp.conf> from "When upstream releases only
369 tarballs", above. You will also need your upstream branch. Above, we
370 pushed this to B<salsa.debian.org>. You will need to clone or fetch
371 from there, instead of relying on B<dgit clone>/B<dgit fetch> alone.
377 % gbp import-orig ../foo_1.2.3.orig.tar.xz
381 or if you have a working watch file
385 % gbp import-orig --uscan
389 =head2 Importing the release
393 % git debrebase new-upstream 1.2.3
397 This invocation of git-debrebase(1) involves a git rebase. You may
398 need to resolve conflicts if the Debian delta queue does not apply
399 cleanly to the new upstream source.
401 If all went well, you can now review the merge of the new upstream
406 git diff debian/1.2.2-1..HEAD -- . ':!debian'
410 Also, diff with I<--name-status> and I<--diff-filter=ADR> to see
411 just the list of added or removed files, which is useful to determine
412 whether there are any new or deleted files that may need accounting
413 for in your copyright file.
415 If you obtained a tarball from upstream, you are ready to try a build.
416 If you merged a git tag from upstream, you will first need to generate
425 =head1 EDITING THE DEBIAN PACKAGING
427 Just make commits on master that change the contents of I<debian/>.
429 =head1 EDITING THE DELTA QUEUE
431 =head2 Adding new patches
433 Adding new patches is straightforward: just make commits touching only
434 files outside of the I<debian/> directory. You can also use tools
435 like git-revert(1), git-am(1) and git-cherry-pick(1).
437 =head2 Editing patches: starting a debrebase
439 git-debrebase(1) is a wrapper around git-rebase(1) which allows us to
440 edit, re-order and delete patches. Run
448 to start an interactive rebase. You can edit, re-order and delete
449 commits just as you would during B<git rebase -i>.
451 =head2 Editing patches: finishing a debrebase
453 After completing the git rebase, your branch will not be a
454 fast-forward of the git HEAD you had before the rebase. This means
455 that we cannot push the branch anywhere. If you are ready to upload,
456 B<dgit push> or B<dgit push-source> will take care of fixing this up
459 If you are not yet ready to upload, and want to push your branch to a
460 git remote such as B<salsa.debian.org>,
464 % git debrebase conclude
468 Note that each time you conclude a debrebase you introduce a
469 pseudomerge into your git history, which may make it harder to read.
470 Try to do all of the editing of the delta queue that you think will be
471 needed for this editing session in a single debrebase, so that there
472 is a single debrebase stitch.
474 =head1 BUILDING AND UPLOADING
476 You can use dpkg-buildpackage(1) for test builds. When you are ready
477 to build for an upload, use B<dgit sbuild>, B<dgit pbuilder> or B<dgit
480 Upload with B<dgit push> or B<dgit push-source>. Remember to pass
481 I<--new> if the package is new in the target suite.
483 In some cases where you used B<git debrebase convert-from-gbp> since
484 the last upload, it is not possible for dgit to make your history
485 fast-forwarding from the history on B<dgit-repos>. In such cases you
486 will have to pass I<--overwrite> to dgit. git-debrebase will normally
487 tell you if this will be needed.
489 Right before uploading, if you did not just already do so, you might
490 want to have git-debrebase(1) shuffle your branch such that the Debian
491 delta queue appears right at the tip of the branch you will push:
500 Note that this will introduce a new pseudomerge.
502 After dgit pushing, be sure to git push to B<salsa.debian.org>, if
505 =head1 HANDLING DFSG-NON-FREE MATERIAL
507 =head2 Illegal material
509 Here we explain how to handle material that is merely DFSG-non-free.
510 Material which is legally dangerous (for example, files which are
511 actually illegal) cannot be handled this way.
513 If you encounter possibly-legally-dangerous material in the upstream
514 source code you should seek advice. It is often best not to make a
515 fuss on a public mailing list (at least, not at first). Instead,
516 email your archive administrators. For Debian that is
517 To: dgit-owner@debian.org, ftpmaster@ftp-master.debian.org
519 =head2 DFSG-non-free: When upstream tags releases in git
521 Our approach is to maintain a DFSG-clean upstream branch, and create
522 tags on this branch for each release that we want to import. We then
523 import those tags per "Importing the release", above. In the case of
524 a new package, we base our initial Debianisation on our first
527 For the first upstream release that requires DFSG filtering:
531 % git checkout -b upstream-dfsg 1.2.3
533 % git commit -m "upstream version 1.2.3 DFSG-cleaned"
534 % git tag -s 1.2.3+dfsg
535 % git checkout master
539 Now either proceed with "Importing the release" on the 1.2.3+dfsg tag,
540 or in the case of a new package,
544 % git branch --unset-upstream
545 % git reset --hard 1.2.3+dfsg
549 and proceed with "INITIAL DEBIANISATION".
551 For subsequent releases (whether or not they require additional
556 % git checkout upstream-dfsg
558 % git rm further-evil.bin # if needed
559 % git commit -m "upstream version 1.2.4 DFSG-cleaned" # if needed
560 % git tag -s 1.2.4+dfsg
561 % git checkout master
562 % # proceed with "Importing the release" on 1.2.4+dfsg tag
566 Our upstream-dfsg branch cannot be pushed to B<dgit-repos>, but since
567 we will need it whenever we import a new upstream version, we must
568 push it somewhere. Assuming that you have already set up an origin
569 remote per the above,
573 % git push --follow-tags -u origin master upstream-dfsg
577 =head2 DFSG-non-free: When upstream releases only tarballs
579 The easiest way to handle this is to add a B<Files-Excluded> field to
580 I<debian/copyright>, and a B<uversionmangle> setting in
581 I<debian/watch>. See uscan(1). Alternatively, see the I<--filter>
582 option detailed in gbp-import-orig(1).
584 =head1 INCORPORATING NMUS
586 In the simplest case,
591 % git merge --ff-only dgit/dgit/sid
595 If that fails, because your branch and the NMUers' work represent
596 divergent branches of development, you have a number of options. Here
597 we describe the two simplest.
599 Note that you should not try to resolve the divergent branches by
600 editing files in I<debian/patches>. Changes there would either cause
601 trouble, or be overwritten by git-debrebase(1).
603 =head2 Rebasing your work onto the NMU
607 % git rebase dgit/dgit/sid
611 If the NMUer added new commits modifying the upstream source, you will
612 probably want to debrebase before your next upload to tidy those up.
614 For example, the NMUer might have used git-revert(1) to unapply one of
615 your patches. A debrebase can be used to strip both the patch and the
616 reversion from the delta queue.
618 =head2 Manually applying the debdiff
620 If you cannot rebase because you have already pushed to
621 B<salsa.debian.org>, say, you can manually apply the NMU debdiff,
622 commit and debrebase. The next B<dgit push> will require
625 =head1 HINTS AND TIPS
627 =head2 Minimising pseudomerges
629 Above we noted that each time you conclude a debrebase, you introduce
630 a pseudomerge into your git history, which may make it harder to read.
632 A simple convention you can use to minimise the number of pseudomerges
633 is to B<git debrebase conclude> only right before you upload or push
634 to B<salsa.debian.org>.
636 It is possible, though much less convenient, to reduce the number of
637 pseudomerges yet further. We debrebase only (i) when importing a new
638 release, and (ii) right before uploading. Instead of editing the
639 existing delta queue, you append fixup commits (and reversions of
640 commits) that alter the upstream source to the required state. You
641 can push and pull to and from B<salsa.debian.org> during this. Just
642 before uploading, you debrebase, once, to tidy everything up.
644 =head2 The debian/patches directory
646 In this workflow, I<debian/patches> is purely an output of
647 git-debrebase(1). You should not make changes there. They will
648 either cause trouble, or be ignored and overwritten by
651 I<debian/patches> will often be out-of-date because git-debrebase(1)
652 will only regenerate it when it needs to. So you should not rely on
653 the information in that directory. When preparing patches to forward
654 upstream, you should use git-format-patch(1) on git commits, rather
655 than sending files from I<debian/patches>.
657 =head2 Upstream branches
659 In this workflow, we specify upstream tags rather than any branches.
661 Except when (i) upstream releases only tarballs, (ii) we require DFSG
662 filtering, or (iii) you also happen to be involved in upstream
663 development, we do not maintain any local branch corresponding to
664 upstream, except temporary branches used to prepare patches for
665 forwarding, and the like.
667 The idea here is that from Debian's point of view, upstream releases
668 are immutable points in history. We want to make sure that we are
669 basing our Debian package on a properly identified upstream version,
670 rather than some arbitrary commit on some branch. Tags are more
673 Upstream's branches remain available as the git remote tracking
674 branches for your upstream remote, e.g. I<remotes/upstream/master>.
676 =head2 The first ever dgit push
678 If this is the first ever dgit push of the package, consider passing
679 I<--deliberately-not-fast-forward> instead of I<--overwrite>. This
680 avoids introducing a new origin commit into your git history. (This
681 origin commit would represent the most recent non-dgit upload of the
682 package, but this should already be represented in your git history.)
684 =head2 Inspecting the history
686 The git history made by git-debrebase can seem complicated.
687 Here are some suggestions for helpful invocations of gitk and git.
688 They can be adapted for other tools like tig(1), git-log(1), magit, etc.
690 History of package in Debian, disregarding history from upstream:
694 % gitk --first-parent
696 In a laundered branch, the delta queue is at the top.
700 History of the packaging, excluding the delta queue:
702 % gitk :/debian :!/debian/patches
704 Just the delta queue (i.e. Debian's changes to upstream):
706 % gitk --first-parent -- :/ :!/debian
708 Full history including old versions of the delta queue:
714 The "Declare fast forward" commits you see have an older history
715 (usually, an older delta queue) as one parent,
716 and a newer history as the other.
717 --date-order makes gitk show the delta queues in the right order.
721 Complete diff since the last upload:
725 % git diff dgit/dgit/sid..HEAD -- :/ :!/debian/patches
727 This includes changes to upstream files.
731 Interdiff of delta queue since last upload, if you really want it:
733 % git debrebase make-patches
734 % git diff dgit/dgit/sid..HEAD -- debian/patches
736 And of course there is:
738 % git debrebase status
740 =head2 Alternative ways to start a debrebase
742 Above we started an interactive debrebase by invoking git-debrebase(1)
751 It is also possible to perform a non-interactive rebase, like this:
755 % git debrebase -- [git-rebase options...]
760 A third alternative is to have git-debrebase(1) shuffle all the Debian
761 changes to the end of your branch, and then manipulate them yourself
762 using git-rebase(1) directly. For example,
767 % git rebase -i HEAD~5 # there are 4 Debian patches
771 If you take this approach, you should be very careful not to start the
773 including before the most recent pseudomerge.
774 git-rebase without a base argument will often
775 start the rebase too early,
776 and should be avoided.
777 Run git-debrebase instead.
778 See also "ILLEGAL OPERATIONS" in git-debrebase(5).
782 dgit(1), dgit(7), git-debrebase(1), git-debrebase(5)
786 This tutorial was written and is maintained by Sean Whitton
787 <spwhitton@spwhitton.name>. It contains contributions from other dgit
788 contributors too - see the dgit copyright file.