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 =head2 When upstream releases only tarballs
139 Because we want to work in git, we need a virtual upstream branch with
140 virtual release tags. gbp-import-orig(1) can manage this for us. To
151 Now create I<debian/gbp.conf>:
156 upstream-branch = upstream
157 debian-branch = master
158 upstream-tag = %(version)s
162 pristine-tar-commit = False
169 gbp-import-orig(1) requires a pre-existing upstream branch:
173 % git add debian/gbp.conf && git commit -m "create gbp.conf"
174 % git checkout --orphan upstream
176 % git commit --allow-empty -m "initial, empty branch for upstream source"
177 % git checkout -f master
181 Then we can import the upstream version:
185 % gbp import-orig --merge-mode=replace ../foo_1.2.2.orig.tar.xz
189 Our upstream branch cannot be pushed to B<dgit-repos>, but since we
190 will need it whenever we import a new upstream version, we must push
191 it somewhere. The usual choice is B<salsa.debian.org>:
195 % git remote add -f origin salsa.debian.org:Debian/foo.git
196 % git push --follow-tags -u origin master upstream
200 You are now ready to proceed as above, making commits to the
201 I<debian/> directory and to the upstream source. As above, for
202 technical reasons, B<it is essential that your first commit introduces
203 the debian/ directory containing at least one file, and does nothing
204 else.> In other words, make a commit introducing I<debian/> before
205 patching the upstream source.
207 =head1 CONVERTING AN EXISTING PACKAGE
209 This section explains how to convert an existing Debian package to
210 this workflow. It should be skipped when debianising a new package.
212 If you have an existing git history that you have pushed to an
213 ordinary git server like B<salsa.debian.org>, we start with that. If
214 you don't already have it locally, you'll need to clone it, and obtain
215 the corresponding orig.tar from the archive:
219 % git clone salsa.debian.org:Debian/foo
221 % dgit setup-new-tree
226 If you don't have any existing git history, or you have history only
227 on the special B<dgit-repos> server, we start with B<dgit clone>:
236 Then we make new upstream tags available:
240 % git remote add -f upstream https://some.upstream/foo.git
244 We now use a B<git debrebase convert-from-*> command to convert your
245 existing history to the git-debrebase(5) data model. Which command
246 you should use depends on some facts about your repository:
250 =item (A) There is no delta queue.
252 If there do not exist any Debian patches, use
256 % git debrebase convert-from-gbp
260 =item (B) There is a delta queue, and patches are unapplied.
262 This is the standard git-buildpackage(1) workflow: there are Debian
263 patches, but the upstream source is committed to git without those
268 % git debrebase convert-from-gbp
272 If you were not previously using dgit to upload your package (i.e. you
273 were not using the workflow described in dgit-maint-gbp(7)), and you
274 happen to have run B<dgit fetch sid> in this clone of the repository,
275 you will need to pass I<--fdiverged> to this command.
277 =item (C) There is a delta queue, and patches are applied.
283 % git debrebase convert-from-dgit-view
289 Finally, you need to ensure that your git HEAD is dgit-compatible,
290 i.e., it is exactly what you would get if you deleted .git, invoked
291 B<dpkg-buildpackage -S>, and then unpacked the resultant source
294 To achieve this, you might need to delete
295 I<debian/source/local-options>. One way to have dgit check your
296 progress is to run B<dgit build-source>.
298 =head1 GIT CONFIGURATION
300 git-debrebase(1) does not yet support using B<git merge> to merge
301 divergent branches of development (see "OTHER MERGES" in
302 git-debrebase(5)). You should configure git such that B<git pull>
303 does not try to merge:
307 % git config --local pull.rebase true
311 Now when you pull work from other Debian contributors, git will rebase
312 your work on top of theirs.
314 If you use this clone for upstream development in addition to
315 Debian packaging work, you may not want to set this global setting.
316 Instead, see the B<branch.autoSetupRebase> and
317 B<branch.E<lt>nameE<gt>.rebase> settings in git-config(5).
319 =head1 IMPORTING NEW UPSTREAM RELEASES
321 There are two steps: obtaining git refs that correspond to the new
322 release, and importing that release using git-debrebase(1).
324 =head2 Obtaining the release
326 =head3 When upstream tags releases in git
334 =head3 When upstream releases only tarballs
336 You will need the I<debian/gbp.conf> from "When upstream releases only
337 tarballs", above. You will also need your upstream branch. Above, we
338 pushed this to B<salsa.debian.org>. You will need to clone or fetch
339 from there, instead of relying on B<dgit clone>/B<dgit fetch> alone.
345 % gbp import-orig --no-merge ../foo_1.2.3.orig.tar.xz
349 or if you have a working watch file
353 % gbp import-orig --no-merge --uscan
357 =head2 Importing the release
361 % git debrebase new-upstream 1.2.3
365 This invocation of git-debrebase(1) involves a git rebase. You may
366 need to resolve conflicts if the Debian delta queue does not apply
367 cleanly to the new upstream source.
369 If all went well, you can now review the merge of the new upstream
374 git diff debian/1.2.2-1..HEAD -- . ':!debian'
378 Pass I<--stat> just to see the list of changed files, which is useful
379 to determine whether there are any new or deleted files to may need
380 accounting for in your copyright file.
382 If you obtained a tarball from upstream, you are ready to try a build.
383 If you merged a git tag from upstream, you will first need to generate
392 =head1 EDITING THE DEBIAN PACKAGING
394 Just make commits on master that change the contents of I<debian/>.
396 =head1 EDITING THE DELTA QUEUE
398 =head2 Adding new patches
400 Adding new patches is straightforward: just make commits touching only
401 files outside of the I<debian/> directory. You can also use tools
402 like git-revert(1), git-am(1) and git-cherry-pick(1).
404 =head2 Editing patches: starting a debrebase
406 git-debrebase(1) is a wrapper around git-rebase(1) which allows us to
407 edit, re-order and delete patches. Run
415 to start an interactive rebase. You can edit, re-order and delete
416 commits just as you would during B<git rebase -i>.
418 =head2 Editing patches: finishing a debrebase
420 After completing the git rebase, your branch will not be a
421 fast-forward of the git HEAD you had before the rebase. This means
422 that we cannot push the branch anywhere. If you are ready to upload,
423 B<dgit push> or B<dgit push-source> will take care of fixing this up
426 If you are not yet ready to upload, and want to push your branch to a
427 git remote such as B<salsa.debian.org>,
431 % git debrebase conclude
435 Note that each time you conclude a debrebase you introduce a
436 pseudomerge into your git history, which may make it harder to read.
437 Try to do all of the editing of the delta queue that you think will be
438 needed for this editing session in a single debrebase, so that there
439 is a single debrebase stitch.
441 =head1 BUILDING AND UPLOADING
443 You can use dpkg-buildpackage(1) for test builds. When you are ready
444 to build for an upload, use B<dgit sbuild>, B<dgit pbuilder> or B<dgit
447 Upload with B<dgit push> or B<dgit push-source>. Remember to pass
448 I<--new> if the package is new in the target suite.
450 In some cases where you used B<git debrebase convert-from-gbp> since
451 the last upload, it is not possible for dgit to make your history
452 fast-forwarding from the history on B<dgit-repos>. In such cases you
453 will have to pass I<--overwrite> to dgit. git-debrebase will normally
454 tell you if this is will be needed.
456 Right before uploading, if you did not just already do so, you might
457 want to have git-debrebase(1) shuffle your branch such that the Debian
458 delta queue appears right at the tip of the branch you will push:
467 Note that this will introduce a new pseudomerge.
469 After dgit pushing, be sure to git push to B<salsa.debian.org>, if
472 =head1 HANDLING DFSG-NON-FREE MATERIAL
474 =head2 Illegal material
476 Here we explain how to handle material that is merely DFSG-non-free.
477 Material which is legally dangerous (for example, files which are
478 actually illegal) cannot be handled this way.
480 If you encounter possibly-legally-dangerous material in the upstream
481 source code you should seek advice. It is often best not to make a
482 fuss on a public mailing list (at least, not at first). Instead,
483 email your archive administrators. For Debian that is
484 To: dgit-owner@debian.org, ftpmaster@ftp-master.debian.org
486 =head2 DFSG-non-free: When upstream tags releases in git
488 Our approach is to maintain a DFSG-clean upstream branch, and create
489 tags on this branch for each release that we want to import. We then
490 import those tags per "Importing the release", above. In the case of
491 a new package, we base our initial Debianisation on our first
494 For the first upstream release that requires DFSG filtering:
498 % git checkout -b upstream-dfsg 1.2.3
500 % git commit -m "upstream version 1.2.3 DFSG-cleaned"
501 % git tag -s 1.2.3+dfsg
502 % git checkout master
506 Now either proceed with "Importing the release" on the 1.2.3+dfsg tag,
507 or in the case of a new package,
511 % git branch --unset-upstream
512 % git reset --hard 1.2.3+dfsg
516 and proceed with "INITIAL DEBIANISATION".
518 For subsequent releases (whether or not they require additional
523 % git checkout upstream-dfsg
525 % git rm further-evil.bin # if needed
526 % git commit -m "upstream version 1.2.4 DFSG-cleaned" # if needed
527 % git tag -s 1.2.4+dfsg
528 % git checkout master
529 % # proceed with "Importing the release" on 1.2.4+dfsg tag
533 Our upstream-dfsg branch cannot be pushed to B<dgit-repos>, but since
534 we will need it whenever we import a new upstream version, we must
535 push it somewhere. Assuming that you have already set up an origin
536 remote per the above,
540 % git push --follow-tags -u origin master upstream-dfsg
544 =head2 DFSG-non-free: When upstream releases only tarballs
546 The easiest way to handle this is to add a B<Files-Excluded> field to
547 I<debian/copyright>, and a B<uversionmangle> setting in
548 I<debian/watch>. See uscan(1). Alternatively, see the I<--filter>
549 option detailed in gbp-import-orig(1).
551 =head1 INCORPORATING NMUS
553 In the simplest case,
558 % git merge --ff-only dgit/dgit/sid
562 If that fails, because your branch and the NMUers work represent
563 divergent branches of development, you have a number of options. Here
564 we describe the two simplest.
566 Note that you should not try to resolve the divergent branches by
567 editing files in I<debian/patches>. Changes there would either cause
568 trouble, or be overwritten by git-debrebase(1).
570 =head2 Rebasing your work onto the NMU
574 % git rebase dgit/dgit/sid
578 If the NMUer added new commits modifying the upstream source, you will
579 probably want to debrebase before your next upload to tidy those up.
581 For example, the NMUer might have used git-revert(1) to unapply one of
582 your patches. A debrebase can be used to strip both the patch and the
583 reversion from the delta queue.
585 =head2 Manually applying the debdiff
587 If you cannot rebase because you have already pushed to
588 B<salsa.debian.org>, say, you can manually apply the NMU debdiff,
589 commit and debrebase. The next B<dgit push> will require
592 =head1 HINTS AND TIPS
594 =head2 Minimising pseudomerges
596 Above we noted that each time you conclude a debrebase, you introduce
597 a pseudomerge into your git history, which may make it harder to read.
599 A simple convention you can use to minimise the number of pseudomerges
600 is to B<git debrebase conclude> only right before you upload or push
601 to B<salsa.debian.org>.
603 It is possible, though much less convenient, to reduce the number of
604 pseudomerges yet further. We debrebase only (i) when importing a new
605 release, and (ii) right before uploading. Instead of editing the
606 existing delta queue, you append fixup commits (and reversions of
607 commits) that alter the upstream source to the required state. You
608 can push and pull to and from B<salsa.debian.org> during this. Just
609 before uploading, you debrebase, once, to tidy everything up.
611 =head2 The debian/patches directory
613 In this workflow, I<debian/patches> is purely an output of
614 git-debrebase(1). You should not make changes there. They will
615 either cause trouble, or be ignored and overwritten by
618 I<debian/patches> will often be out-of-date because git-debrebase(1)
619 will only regenerate it when it needs to. So you should not rely on
620 the information in that directory. When preparing patches to forward
621 upstream, you should use git-format-patch(1) on git commits, rather
622 than sending files from I<debian/patches>.
624 =head2 Upstream branches
626 In this workflow, we specify upstream tags rather than any branches.
628 Except when (i) upstream releases only tarballs, (ii) we require DFSG
629 filtering, or (iii) you also happen to be involved in upstream
630 development, we do not maintain any local branch corresponding to
631 upstream, except temporary branches used to prepare patches for
632 forwarding, and the like.
634 The idea here is that from Debian's point of view, upstream releases
635 are immutable points in history. We want to make sure that we are
636 basing our Debian package on a properly identified upstream version,
637 rather than some arbitrary commit on some branch. Tags are more
640 Upstream's branches remain available as the git remote tracking
641 branches for your upstream remote, e.g. I<remotes/upstream/master>.
643 =head2 The first ever dgit push
645 If this is the first ever dgit push of the package, consider passing
646 I<--deliberately-not-fast-forward> instead of I<--overwrite>. This
647 avoids introducing a new origin commit into your git history. (This
648 origin commit would represent the most recent non-dgit upload of the
649 package, but this should already be represented in your git history.)
651 =head2 Inspecting the history
653 The git history made by git-debrebase can seem complicated.
654 Here are some suggestions for helpful invocations of gitk and git.
655 They can be adapted for other tools like tig(1), git-log(1), magit, etc.
657 History of package in Debian, disregarding history from upstream:
661 % gitk --first-parent
663 In a laundered branch, the delta queue is at the top.
667 History of the packaging, excluding the delta queue:
669 % gitk :/debian :!/debian/patches
671 Just the delta queue (i.e. Debian's changes to upstream):
673 % gitk --first-parent -- :/ :!/debian
675 Full history including old versions of the delta queue:
681 The "Declare fast forward" commits you see have an older history
682 (usually, an older delta queue) as one parent,
683 and a newer history as the other.
684 --date-order makes gitk show the delta queues in the right order.
688 Complete diff since the last upload:
692 % git diff dgit/dgit/sid..HEAD -- :/ :!/debian/patches
694 This includes changes to upstream files.
698 Interdiff of delta queue since last upload, if you really want it:
700 % git debrebase make-patches
701 % git diff dgit/dgit/sid..HEAD -- debian/patches
703 And of course there is:
705 % git debrebase status
707 =head2 Alternative ways to start a debrebase
709 Above we started an interactive debrebase by invoking git-debrebase(1)
718 It is also possible to perform a non-interactive rebase, like this:
722 % git debrebase -- [git-rebase options...]
727 A third alternative is to have git-debrebase(1) shuffle all the Debian
728 changes to the end of your branch, and then manipulate them yourself
729 using git-rebase(1) directly. For example,
734 % git rebase -i HEAD~5 # there are 4 Debian patches
738 If you take this approach, you should be very careful not to start the
740 including before the most recent pseudomerge.
741 git-rebase without a base argument will often
742 start the rebase too early,
743 and should be avoided.
744 Run git-debrebase instead.
745 See also "ILLEGAL OPERATIONS" in git-debrebase(5).
749 dgit(1), dgit(7), git-debrebase(1), git-debrebase(5)
753 This tutorial was written and is maintained by Sean Whitton
754 <spwhitton@spwhitton.name>. It contains contributions from other dgit
755 contributors too - see the dgit copyright file.