1dgit-maint-merge(7)                  dgit                  dgit-maint-merge(7)
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NAME

6       dgit - tutorial for package maintainers, using a workflow centered
7       around git-merge(1)
8

INTRODUCTION

10       This document describes elements of a workflow for maintaining a non-
11       native Debian package using dgit.  The workflow makes the following
12       opinionated assumptions:
13
14       ·   Git histories should be the non-linear histories produced by
15           git-merge(1), preserving all information about divergent
16           development that was later brought together.
17
18       ·   Maintaining convenient and powerful git workflows takes priority
19           over the usefulness of the raw Debian source package.  The Debian
20           archive is thought of as an output format.
21
22           For example, we don't spend time curating a series of quilt
23           patches.  However, in straightforward cases, the information such a
24           series would contain is readily available from dgit-repos.
25
26       ·   It is more important to have the Debian package's git history be a
27           descendent of upstream's git history than to use exactly the
28           orig.tar that upstream makes available for download.
29
30       This workflow is less suitable for some packages.  When the Debian
31       delta contains multiple pieces which interact, or which you aren't
32       going to be able to upstream soon, it might be preferable to maintain
33       the delta as a rebasing patch series.  For such a workflow see for
34       example dgit-maint-debrebase(7) and dgit-maint-gbp(7).
35

INITIAL DEBIANISATION

37       This section explains how to start using this workflow with a new
38       package.  It should be skipped when converting an existing package to
39       this workflow.
40
41   When upstream tags releases in git
42       Suppose that the latest stable upstream release is 1.2.2, and this has
43       been tagged '1.2.2' by upstream.
44
45           % git clone -oupstream https://some.upstream/foo.git
46           % cd foo
47           % git verify-tag 1.2.2
48           % git reset --hard 1.2.2
49           % git branch --unset-upstream
50
51       The final command detaches your master branch from the upstream remote,
52       so that git doesn't try to push anything there, or merge unreleased
53       upstream commits.  If you want to maintain a copy of your packaging
54       branch on salsa.debian.org in addition to dgit-repos, you can do
55       something like this:
56
57           % git remote add -f origin salsa.debian.org:Debian/foo.git
58           % git push --follow-tags -u origin master
59
60       Now go ahead and Debianise your package.  Just make commits on the
61       master branch, adding things in the debian/ directory.  If you need to
62       patch the upstream source, just make commits that change files outside
63       of the debian/ directory.  It is best to separate commits that touch
64       debian/ from commits that touch upstream source, so that the latter can
65       be cherry-picked by upstream.
66
67       Note that there is no need to maintain a separate 'upstream' branch,
68       unless you also happen to be involved in upstream development.  We work
69       with upstream tags rather than any branches, except when forwarding
70       patches (see FORWARDING PATCHES UPSTREAM, below).
71
72       Finally, you need an orig tarball:
73
74           % git deborig
75
76       See git-deborig(1) if this fails.
77
78       This tarball is ephemeral and easily regenerated, so we don't commit it
79       anywhere (e.g. with tools like pristine-tar(1)).
80
81       Verifying upstream's tarball releases
82
83           It can be a good idea to compare upstream's released tarballs with
84           the release tags, at least for the first upload of the package.  If
85           they are different, you might need to add some additional steps to
86           your debian/rules, such as running autotools.
87
88           A convenient way to perform this check is to import the tarball as
89           described in the following section, using a different value for
90           'upstream-tag', and then use git-diff(1) to compare the imported
91           tarball to the release tag.  If they are the same, you can use
92           upstream's tarball instead of running git-deborig(1).
93
94   When upstream releases only tarballs
95       We need a virtual upstream branch with virtual release tags.
96       gbp-import-orig(1) can manage this for us.  To begin
97
98           % mkdir foo
99           % cd foo
100           % git init
101
102       Now create debian/gbp.conf:
103
104           [DEFAULT]
105           upstream-branch = upstream
106           debian-branch = master
107           upstream-tag = %(version)s
108
109           sign-tags = True
110           pristine-tar = False
111           pristine-tar-commit = False
112
113           [import-orig]
114           merge-mode = merge
115
116       gbp-import-orig(1) requires a pre-existing upstream branch:
117
118           % git add debian/gbp.conf && git commit -m "create gbp.conf"
119           % git checkout --orphan upstream
120           % git rm -rf .
121           % git commit --allow-empty -m "initial, empty branch for upstream source"
122           % git checkout -f master
123
124       Then we can import the upstream version:
125
126           % gbp import-orig --merge-mode=replace ../foo_1.2.2.orig.tar.xz
127
128       Our upstream branch cannot be pushed to dgit-repos, but since we will
129       need it whenever we import a new upstream version, we must push it
130       somewhere.  The usual choice is salsa.debian.org:
131
132           % git remote add -f origin salsa.debian.org:Debian/foo.git
133           % git push --follow-tags -u origin master upstream
134
135       You are now ready to proceed as above, making commits to both the
136       upstream source and the debian/ directory.
137

CONVERTING AN EXISTING PACKAGE

139       This section explains how to convert an existing Debian package to this
140       workflow.  It should be skipped when debianising a new package.
141
142   No existing git history
143           % dgit clone foo
144           % cd foo
145           % git remote add -f upstream https://some.upstream/foo.git
146
147   Existing git history using another workflow
148       First, if you don't already have the git history locally, clone it, and
149       obtain the corresponding orig.tar from the archive:
150
151           % git clone git.debian.org:collab-maint/foo
152           % cd foo
153           % origtargz
154
155       Now dump any existing patch queue:
156
157           % git rm -rf debian/patches
158           % git commit -m "drop existing quilt patch queue"
159
160       Then make new upstream tags available:
161
162           % git remote add -f upstream https://some.upstream/foo.git
163
164       Now you simply need to ensure that your git HEAD is dgit-compatible,
165       i.e., it is exactly what you would get if you ran dpkg-buildpackage
166       -i'(?:^|/)\.git(?:/|$)' -I.git -S and then unpacked the resultant
167       source package.
168
169       To achieve this, you might need to delete debian/source/local-options.
170       One way to have dgit check your progress is to run dgit build-source.
171
172       The first dgit push will require --overwrite.  If this is the first
173       ever dgit push of the package, consider passing
174       --deliberately-not-fast-forward instead of --overwrite.  This avoids
175       introducing a new origin commit into your git history.  (This origin
176       commit would represent the most recent non-dgit upload of the package,
177       but this should already be represented in your git history.)
178

SOURCE PACKAGE CONFIGURATION

180   debian/source/options
181       We set some source package options such that dgit can transparently
182       handle the "dropping" and "refreshing" of changes to the upstream
183       source:
184
185           single-debian-patch
186           auto-commit
187
188       You don't need to create this file if you are using the version 1.0
189       source package format.
190
191   Sample text for debian/source/patch-header
192       It is a good idea to explain how a user can obtain a breakdown of the
193       changes to the upstream source:
194
195           The Debian packaging of foo is maintained in git, using the merging
196           workflow described in dgit-maint-merge(7).  There isn't a patch
197           queue that can be represented as a quilt series.
198
199           A detailed breakdown of the changes is available from their
200           canonical representation - git commits in the packaging repository.
201           For example, to see the changes made by the Debian maintainer in
202           the first upload of upstream version 1.2.3, you could use:
203
204               % git clone https://git.dgit.debian.org/foo
205               % cd foo
206               % git log --oneline 1.2.3..debian/1.2.3-1 -- . ':!debian'
207
208           (If you have dgit, use `dgit clone foo`, rather than plain `git
209           clone`.)
210
211           A single combined diff, containing all the changes, follows.
212
213       If you are using the version 1.0 source package format, this text
214       should be added to README.source instead.  The version 1.0 source
215       package format ignores debian/source/patch-header.
216
217       If you're using the version 3.0 (quilt) source package format, you
218       could add this text to README.source instead of
219       debian/source/patch-header, but this might distract from more important
220       information present in README.source.
221

BUILDING AND UPLOADING

223       Use dgit build, dgit sbuild, dgit pbuilder, dgit cowbuilder, dgit push-
224       source, and dgit push as detailed in dgit(1).  If any command fails,
225       dgit will provide a carefully-worded error message explaining what you
226       should do.  If it's not clear, file a bug against dgit.  Remember to
227       pass --new for the first upload.
228
229       As an alternative to dgit build and friends, you can use a tool like
230       gitpkg(1).  This works because like dgit, gitpkg(1) enforces that HEAD
231       has exactly the contents of the source package.  gitpkg(1) is highly
232       configurable, and one dgit user reports using it to produce and test
233       multiple source packages, from different branches corresponding to each
234       of the current Debian suites.
235
236       If you want to skip dgit's checks while iterating on a problem with the
237       package build (for example, you don't want to commit your changes to
238       git), you can just run dpkg-buildpackage(1) or debuild(1) instead.
239

NEW UPSTREAM RELEASES

241   Obtaining the release
242       When upstream tags releases in git
243
244           % git remote update
245
246       When upstream releases only tarballs
247
248       You will need the debian/gbp.conf from "When upstream releases only
249       tarballs", above.  You will also need your upstream branch.  Above, we
250       pushed this to salsa.debian.org.  You will need to clone or fetch from
251       there, instead of relying on dgit clone/dgit fetch alone.
252
253       Then, either
254
255           % gbp import-orig --no-merge ../foo_1.2.3.orig.tar.xz
256
257       or if you have a working watch file
258
259           % gbp import-orig --no-merge --uscan
260
261   Reviewing & merging the release
262       It's a good idea to preview the merge of the new upstream release.
263       First, just check for any new or deleted files that may need accounting
264       for in your copyright file:
265
266           % git diff --stat master..1.2.3 -- . ':!debian'
267
268       You can then review the full merge diff:
269
270           % git merge-tree `git merge-base master 1.2.3` master 1.2.3 | $PAGER
271
272       Once you're satisfied with what will be merged, update your package:
273
274           % git merge 1.2.3
275           % dch -v1.2.3-1 New upstream release.
276           % git add debian/changelog && git commit -m changelog
277
278       If you obtained a tarball from upstream, you are ready to try a build.
279       If you merged a git tag from upstream, you will first need to generate
280       a tarball:
281
282           % git deborig
283

HANDLING DFSG-NON-FREE MATERIAL

285   When upstream tags releases in git
286       We create a DFSG-clean tag to merge to master:
287
288           % git checkout -b pre-dfsg 1.2.3
289           % git rm evil.bin
290           % git commit -m "upstream version 1.2.3 DFSG-cleaned"
291           % git tag -s 1.2.3+dfsg
292           % git checkout master
293           % git branch -D pre-dfsg
294
295       Before merging the new 1.2.3+dfsg tag to master, you should first
296       determine whether it would be legally dangerous for the non-free
297       material to be publicly accessible in the git history on dgit-repos.
298
299       If it would be dangerous, there is a big problem; in this case please
300       consult your archive administrators (for Debian this is the dgit
301       administrator dgit-owner@debian.org and the ftpmasters
302       ftpmaster@ftp-master.debian.org).
303
304   When upstream releases only tarballs
305       The easiest way to handle this is to add a Files-Excluded field to
306       debian/copyright, and a uversionmangle setting in debian/watch.  See
307       uscan(1).  Alternatively, see the --filter option detailed in
308       gbp-import-orig(1).
309

FORWARDING PATCHES UPSTREAM

311       The basic steps are:
312
313       1.  Create a new branch based off upstream's master branch.
314
315       2.  git-cherry-pick(1) commits from your master branch onto your new
316           branch.
317
318       3.  Push the branch somewhere and ask upstream to merge it, or use
319           git-format-patch(1) or git-request-pull(1).
320
321       For example (and it is only an example):
322
323           % # fork foo.git on GitHub
324           % git remote add -f fork git@github.com:spwhitton/foo.git
325           % git checkout -b fix-error upstream/master
326           % git config branch.fix-error.pushRemote fork
327           % git cherry-pick master^2
328           % git push
329           % # submit pull request on GitHub
330
331       Note that when you merge an upstream release containing your forwarded
332       patches, git and dgit will transparently handle "dropping" the patches
333       that have been forwarded, "retaining" the ones that haven't.
334

INCORPORATING NMUS

336           % dgit pull
337
338       Alternatively, you can apply the NMU diff to your repository.  The next
339       push will then require --overwrite.
340

SEE ALSO

342       dgit(1), dgit(7)
343

AUTHOR

345       This tutorial was written and is maintained by Sean Whitton
346       <spwhitton@spwhitton.name>.  It contains contributions from other dgit
347       contributors too - see the dgit copyright file.
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