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
177 Now create I<debian/gbp.conf>:
182 upstream-branch = upstream
183 debian-branch = master
184 upstream-tag = %(version)s
188 pristine-tar-commit = False
195 gbp-import-orig(1) requires a pre-existing upstream branch:
199 % git add debian/gbp.conf && git commit -m "create gbp.conf"
200 % git checkout --orphan upstream
202 % git commit --allow-empty -m "initial, empty branch for upstream source"
203 % git checkout -f master
207 Then we can import the upstream version:
211 % gbp import-orig --merge-mode=replace ../foo_1.2.2.orig.tar.xz
215 Our upstream branch cannot be pushed to B<dgit-repos>, but since we
216 will need it whenever we import a new upstream version, we must push
217 it somewhere. The usual choice is B<salsa.debian.org>:
221 % git remote add -f origin salsa.debian.org:Debian/foo.git
222 % git push --follow-tags -u origin master upstream
226 You are now ready to proceed as above, making commits to the
227 I<debian/> directory and to the upstream source. As above, for
228 technical reasons, B<it is essential that your first commit introduces
229 the debian/ directory containing at least one file, and does nothing
230 else.> In other words, make a commit introducing I<debian/> before
231 patching the upstream source.
233 =head1 CONVERTING AN EXISTING PACKAGE
235 This section explains how to convert an existing Debian package to
236 this workflow. It should be skipped when debianising a new package.
238 If you have an existing git history that you have pushed to an
239 ordinary git server like B<salsa.debian.org>, we start with that. If
240 you don't already have it locally, you'll need to clone it, and obtain
241 the corresponding orig.tar from the archive:
245 % git clone salsa.debian.org:Debian/foo
247 % dgit setup-new-tree
252 If you don't have any existing git history, or you have history only
253 on the special B<dgit-repos> server, we start with B<dgit clone>:
262 Then we make new upstream tags available:
266 % git remote add -f upstream https://some.upstream/foo.git
270 We now use a B<git debrebase convert-from-*> command to convert your
271 existing history to the git-debrebase(5) data model. Which command
272 you should use depends on some facts about your repository:
276 =item (A) There is no delta queue.
278 If there do not exist any Debian patches, use
282 % git debrebase convert-from-gbp
286 =item (B) There is a delta queue, and patches are unapplied.
288 This is the standard git-buildpackage(1) workflow: there are Debian
289 patches, but the upstream source is committed to git without those
294 % git debrebase convert-from-gbp
298 If you were not previously using dgit to upload your package (i.e. you
299 were not using the workflow described in dgit-maint-gbp(7)), and you
300 happen to have run B<dgit fetch sid> in this clone of the repository,
301 you will need to pass I<--fdiverged> to this command.
303 =item (C) There is a delta queue, and patches are applied.
309 % git debrebase convert-from-dgit-view
315 Finally, you need to ensure that your git HEAD is dgit-compatible,
316 i.e., it is exactly what you would get if you deleted .git, invoked
317 B<dpkg-buildpackage -S>, and then unpacked the resultant source
320 To achieve this, you might need to delete
321 I<debian/source/local-options>. One way to have dgit check your
322 progress is to run B<dgit build-source>.
324 =head1 GIT CONFIGURATION
326 git-debrebase(1) does not yet support using B<git merge> to merge
327 divergent branches of development (see "OTHER MERGES" in
328 git-debrebase(5)). You should configure git such that B<git pull>
329 does not try to merge:
333 % git config --local pull.rebase true
337 Now when you pull work from other Debian contributors, git will rebase
338 your work on top of theirs.
340 If you use this clone for upstream development in addition to
341 Debian packaging work, you may not want to set this global setting.
342 Instead, see the B<branch.autoSetupRebase> and
343 B<branch.E<lt>nameE<gt>.rebase> settings in git-config(5).
345 =head1 IMPORTING NEW UPSTREAM RELEASES
347 There are two steps: obtaining git refs that correspond to the new
348 release, and importing that release using git-debrebase(1).
350 =head2 Obtaining the release
352 =head3 When upstream tags releases in git
360 If you want to package an untagged upstream commit (because upstream
361 does not tag releases or because you want to package an upstream
362 development snapshot), see "Using untagged upstream commits" above.
364 =head3 When upstream releases only tarballs
366 You will need the I<debian/gbp.conf> from "When upstream releases only
367 tarballs", above. You will also need your upstream branch. Above, we
368 pushed this to B<salsa.debian.org>. You will need to clone or fetch
369 from there, instead of relying on B<dgit clone>/B<dgit fetch> alone.
375 % gbp import-orig --no-merge ../foo_1.2.3.orig.tar.xz
379 or if you have a working watch file
383 % gbp import-orig --no-merge --uscan
387 =head2 Importing the release
391 % git debrebase new-upstream 1.2.3
395 This invocation of git-debrebase(1) involves a git rebase. You may
396 need to resolve conflicts if the Debian delta queue does not apply
397 cleanly to the new upstream source.
399 If all went well, you can now review the merge of the new upstream
404 git diff debian/1.2.2-1..HEAD -- . ':!debian'
408 Also, diff with I<--name-status> and I<--diff-filter=ADR> to see
409 just the list of added or removed files, which is useful to determine
410 whether there are any new or deleted files that may need accounting
411 for in your copyright file.
413 If you obtained a tarball from upstream, you are ready to try a build.
414 If you merged a git tag from upstream, you will first need to generate
423 =head1 EDITING THE DEBIAN PACKAGING
425 Just make commits on master that change the contents of I<debian/>.
427 =head1 EDITING THE DELTA QUEUE
429 =head2 Adding new patches
431 Adding new patches is straightforward: just make commits touching only
432 files outside of the I<debian/> directory. You can also use tools
433 like git-revert(1), git-am(1) and git-cherry-pick(1).
435 =head2 Editing patches: starting a debrebase
437 git-debrebase(1) is a wrapper around git-rebase(1) which allows us to
438 edit, re-order and delete patches. Run
446 to start an interactive rebase. You can edit, re-order and delete
447 commits just as you would during B<git rebase -i>.
449 =head2 Editing patches: finishing a debrebase
451 After completing the git rebase, your branch will not be a
452 fast-forward of the git HEAD you had before the rebase. This means
453 that we cannot push the branch anywhere. If you are ready to upload,
454 B<dgit push> or B<dgit push-source> will take care of fixing this up
457 If you are not yet ready to upload, and want to push your branch to a
458 git remote such as B<salsa.debian.org>,
462 % git debrebase conclude
466 Note that each time you conclude a debrebase you introduce a
467 pseudomerge into your git history, which may make it harder to read.
468 Try to do all of the editing of the delta queue that you think will be
469 needed for this editing session in a single debrebase, so that there
470 is a single debrebase stitch.
472 =head1 BUILDING AND UPLOADING
474 You can use dpkg-buildpackage(1) for test builds. When you are ready
475 to build for an upload, use B<dgit sbuild>, B<dgit pbuilder> or B<dgit
478 Upload with B<dgit push> or B<dgit push-source>. Remember to pass
479 I<--new> if the package is new in the target suite.
481 In some cases where you used B<git debrebase convert-from-gbp> since
482 the last upload, it is not possible for dgit to make your history
483 fast-forwarding from the history on B<dgit-repos>. In such cases you
484 will have to pass I<--overwrite> to dgit. git-debrebase will normally
485 tell you if this will be needed.
487 Right before uploading, if you did not just already do so, you might
488 want to have git-debrebase(1) shuffle your branch such that the Debian
489 delta queue appears right at the tip of the branch you will push:
498 Note that this will introduce a new pseudomerge.
500 After dgit pushing, be sure to git push to B<salsa.debian.org>, if
503 =head1 HANDLING DFSG-NON-FREE MATERIAL
505 =head2 Illegal material
507 Here we explain how to handle material that is merely DFSG-non-free.
508 Material which is legally dangerous (for example, files which are
509 actually illegal) cannot be handled this way.
511 If you encounter possibly-legally-dangerous material in the upstream
512 source code you should seek advice. It is often best not to make a
513 fuss on a public mailing list (at least, not at first). Instead,
514 email your archive administrators. For Debian that is
515 To: dgit-owner@debian.org, ftpmaster@ftp-master.debian.org
517 =head2 DFSG-non-free: When upstream tags releases in git
519 Our approach is to maintain a DFSG-clean upstream branch, and create
520 tags on this branch for each release that we want to import. We then
521 import those tags per "Importing the release", above. In the case of
522 a new package, we base our initial Debianisation on our first
525 For the first upstream release that requires DFSG filtering:
529 % git checkout -b upstream-dfsg 1.2.3
531 % git commit -m "upstream version 1.2.3 DFSG-cleaned"
532 % git tag -s 1.2.3+dfsg
533 % git checkout master
537 Now either proceed with "Importing the release" on the 1.2.3+dfsg tag,
538 or in the case of a new package,
542 % git branch --unset-upstream
543 % git reset --hard 1.2.3+dfsg
547 and proceed with "INITIAL DEBIANISATION".
549 For subsequent releases (whether or not they require additional
554 % git checkout upstream-dfsg
556 % git rm further-evil.bin # if needed
557 % git commit -m "upstream version 1.2.4 DFSG-cleaned" # if needed
558 % git tag -s 1.2.4+dfsg
559 % git checkout master
560 % # proceed with "Importing the release" on 1.2.4+dfsg tag
564 Our upstream-dfsg branch cannot be pushed to B<dgit-repos>, but since
565 we will need it whenever we import a new upstream version, we must
566 push it somewhere. Assuming that you have already set up an origin
567 remote per the above,
571 % git push --follow-tags -u origin master upstream-dfsg
575 =head2 DFSG-non-free: When upstream releases only tarballs
577 The easiest way to handle this is to add a B<Files-Excluded> field to
578 I<debian/copyright>, and a B<uversionmangle> setting in
579 I<debian/watch>. See uscan(1). Alternatively, see the I<--filter>
580 option detailed in gbp-import-orig(1).
582 =head1 INCORPORATING NMUS
584 In the simplest case,
589 % git merge --ff-only dgit/dgit/sid
593 If that fails, because your branch and the NMUers' work represent
594 divergent branches of development, you have a number of options. Here
595 we describe the two simplest.
597 Note that you should not try to resolve the divergent branches by
598 editing files in I<debian/patches>. Changes there would either cause
599 trouble, or be overwritten by git-debrebase(1).
601 =head2 Rebasing your work onto the NMU
605 % git rebase dgit/dgit/sid
609 If the NMUer added new commits modifying the upstream source, you will
610 probably want to debrebase before your next upload to tidy those up.
612 For example, the NMUer might have used git-revert(1) to unapply one of
613 your patches. A debrebase can be used to strip both the patch and the
614 reversion from the delta queue.
616 =head2 Manually applying the debdiff
618 If you cannot rebase because you have already pushed to
619 B<salsa.debian.org>, say, you can manually apply the NMU debdiff,
620 commit and debrebase. The next B<dgit push> will require
623 =head1 HINTS AND TIPS
625 =head2 Minimising pseudomerges
627 Above we noted that each time you conclude a debrebase, you introduce
628 a pseudomerge into your git history, which may make it harder to read.
630 A simple convention you can use to minimise the number of pseudomerges
631 is to B<git debrebase conclude> only right before you upload or push
632 to B<salsa.debian.org>.
634 It is possible, though much less convenient, to reduce the number of
635 pseudomerges yet further. We debrebase only (i) when importing a new
636 release, and (ii) right before uploading. Instead of editing the
637 existing delta queue, you append fixup commits (and reversions of
638 commits) that alter the upstream source to the required state. You
639 can push and pull to and from B<salsa.debian.org> during this. Just
640 before uploading, you debrebase, once, to tidy everything up.
642 =head2 The debian/patches directory
644 In this workflow, I<debian/patches> is purely an output of
645 git-debrebase(1). You should not make changes there. They will
646 either cause trouble, or be ignored and overwritten by
649 I<debian/patches> will often be out-of-date because git-debrebase(1)
650 will only regenerate it when it needs to. So you should not rely on
651 the information in that directory. When preparing patches to forward
652 upstream, you should use git-format-patch(1) on git commits, rather
653 than sending files from I<debian/patches>.
655 =head2 Upstream branches
657 In this workflow, we specify upstream tags rather than any branches.
659 Except when (i) upstream releases only tarballs, (ii) we require DFSG
660 filtering, or (iii) you also happen to be involved in upstream
661 development, we do not maintain any local branch corresponding to
662 upstream, except temporary branches used to prepare patches for
663 forwarding, and the like.
665 The idea here is that from Debian's point of view, upstream releases
666 are immutable points in history. We want to make sure that we are
667 basing our Debian package on a properly identified upstream version,
668 rather than some arbitrary commit on some branch. Tags are more
671 Upstream's branches remain available as the git remote tracking
672 branches for your upstream remote, e.g. I<remotes/upstream/master>.
674 =head2 The first ever dgit push
676 If this is the first ever dgit push of the package, consider passing
677 I<--deliberately-not-fast-forward> instead of I<--overwrite>. This
678 avoids introducing a new origin commit into your git history. (This
679 origin commit would represent the most recent non-dgit upload of the
680 package, but this should already be represented in your git history.)
682 =head2 Inspecting the history
684 The git history made by git-debrebase can seem complicated.
685 Here are some suggestions for helpful invocations of gitk and git.
686 They can be adapted for other tools like tig(1), git-log(1), magit, etc.
688 History of package in Debian, disregarding history from upstream:
692 % gitk --first-parent
694 In a laundered branch, the delta queue is at the top.
698 History of the packaging, excluding the delta queue:
700 % gitk :/debian :!/debian/patches
702 Just the delta queue (i.e. Debian's changes to upstream):
704 % gitk --first-parent -- :/ :!/debian
706 Full history including old versions of the delta queue:
712 The "Declare fast forward" commits you see have an older history
713 (usually, an older delta queue) as one parent,
714 and a newer history as the other.
715 --date-order makes gitk show the delta queues in the right order.
719 Complete diff since the last upload:
723 % git diff dgit/dgit/sid..HEAD -- :/ :!/debian/patches
725 This includes changes to upstream files.
729 Interdiff of delta queue since last upload, if you really want it:
731 % git debrebase make-patches
732 % git diff dgit/dgit/sid..HEAD -- debian/patches
734 And of course there is:
736 % git debrebase status
738 =head2 Alternative ways to start a debrebase
740 Above we started an interactive debrebase by invoking git-debrebase(1)
749 It is also possible to perform a non-interactive rebase, like this:
753 % git debrebase -- [git-rebase options...]
758 A third alternative is to have git-debrebase(1) shuffle all the Debian
759 changes to the end of your branch, and then manipulate them yourself
760 using git-rebase(1) directly. For example,
765 % git rebase -i HEAD~5 # there are 4 Debian patches
769 If you take this approach, you should be very careful not to start the
771 including before the most recent pseudomerge.
772 git-rebase without a base argument will often
773 start the rebase too early,
774 and should be avoided.
775 Run git-debrebase instead.
776 See also "ILLEGAL OPERATIONS" in git-debrebase(5).
780 dgit(1), dgit(7), git-debrebase(1), git-debrebase(5)
784 This tutorial was written and is maintained by Sean Whitton
785 <spwhitton@spwhitton.name>. It contains contributions from other dgit
786 contributors too - see the dgit copyright file.