1 .TH dgit 7 "" "Debian Project" "dgit"
3 dgit \- principles of operation
6 treats the Debian archive as a version control system, and
7 bidirectionally gateways between the archive and git. The git view of
8 the package can contain the usual upstream git history, and will be
9 augmented by commits representing uploads done by other developers not
10 using dgit. This git history is stored in a canonical location known
13 which lives on a dedicated git server.
15 git branches suitable for use with dgit
16 can be edited directly in git,
17 and used directly for building binary packages.
18 They can be shared using all conventional means for sharing git
20 It is not necessary to use dgit to work with dgitish git branches.
21 However, dgit is (usually) needed in order to convert to or from
22 Debian-format source packages.
26 Reference manual and documentation catalogue.
29 Tutorials and workflow guides. See dgit(1) for a list.
31 You may use any suitable git workflow with dgit, provided you
32 satisfy dgit's requirements:
34 dgit maintains a pseudo-remote called
36 with one branch per suite. This remote cannot be used with
41 repository for each package contains one ref per suite named
42 \fBrefs/dgit/\fR\fIsuite\fR. These should be pushed to only by
43 dgit. They are fast forwarding. Each push on this branch
44 corresponds to an upload (or attempted upload).
46 However, it is perfectly fine to have other branches in dgit-repos;
47 normally the dgit-repos repo for the package will be accessible via
48 the remote name `origin'.
50 dgit push will also make signed tags called
51 .BI archive/debian/ version
52 (with version encoded a la DEP-14)
53 and push them to dgit-repos. These are used at the
54 server to authenticate pushes.
56 Uploads made by dgit contain an additional field
58 in the source package .dsc. (This is added by dgit push.)
59 This specifies: a commit (an ancestor of the dgit/suite
60 branch) whose tree is identical to the unpacked source upload;
61 the distro to which the upload was made;
62 a tag name which can be used to fetch the git commits;
64 a url to use as a hint for the dgit git server for that distro.
66 Uploads not made by dgit are represented in git by commits which are
67 synthesised by dgit. The tree of each such commit corresponds to the
68 unpacked source; there is a
69 commit with the contents,
71 pseudo-merge from last known upload - that is, from the contents of
72 the dgit/suite branch.
73 Depending on the source package format,
74 the contents commit may have a more complex structure,
75 but ultimately it will be a convergence of stubby branches
76 from origin commits representing the components of the source package.
78 dgit expects trees that it works with to have a
80 (pseudo) remote. This refers to the dgit-created git view of
81 the corresponding archive.
83 The dgit archive tracking view is synthesised locally,
86 The tracking view is always a descendant of the
87 dgit-repos suite branch (if one exists),
88 but may be ahead of it if uploads have been done without dgit.
89 The archive tracking view is always fast forwarding within
92 dgit push can operate on any commit which is a descendant of
93 the suite tracking branch.
95 dgit does not make a systematic record of
96 its imports of orig tarball(s).
97 So it does not work by finding git tags or branches
98 referring to orig tarball(s).
100 orig tarballs are downloaded (by dgit clone) into the parent
101 directory, as with a traditional (non-gitish) dpkg-source workflow.
102 You need to retain these tarballs in the parent directory for dgit
104 (They are not needed for purely-git-based workflows.)
106 dgit repositories could be cloned with standard (git) methods.
108 the dgit repositories do not contain uploads not made with dgit.
110 for sourceful builds / uploads the orig
111 tarball(s) will need to be present in the parent directory.
113 To a user looking at the archive, changes pushed
117 changes made in an NMU: in a `3.0 (quilt)' package the delta from the
118 previous upload is recorded in new patch(es) constructed by dpkg-source.
120 dgit can synthesize a combined view of several underlying suites.
121 This is requested by specifying, for
123 a comma-separated list:
125 .IR mainsuite \fB,\fR subsuite ...
127 This facility is available with dgit clone, fetch and pull, only.
129 dgit will fetch the same package from each specified underlying suite,
130 separately (as if with dgit fetch).
131 dgit will then generate a pseudomerge commit
132 on the tracking branch
133 .BI remotes/dgit/dgit/ suite
134 which has the tip of each of the underlying suites
136 and which contains the same as the suite which
137 has the highest version of the package.
139 The package must exist in mainsuite,
140 but need not exist in the subsuites.
142 If a specified subsuite starts with
144 then mainsuite is prepended.
148 means to look for the package in stable, and stable-security,
149 taking whichever is newer.
150 If stable is currently jessie,
151 dgit clone would leave you on the branch
152 .BR dgit/jessie,-security .
154 Combined suites are not supported by the dgit build operations.
155 This is because those options are intended for building for
156 uploading source packages,
157 and look in the changelog to find the relevant suite.
158 It does not make sense to name a dgit-synthesised combined suite
160 or to try to upload to it.
162 When using this facility, it is important to always specify the
163 same suites in the same order:
164 dgit will not be make a coherent fast-forwarding history
167 The history generated by this feature is not normally suitable
168 for merging back into upstreams,
169 as it necessarily contains unattractive pseudomerges.
171 Because the synthesis
172 of the suite tracking branches
173 is done locally based only on the current archive state,
174 it will not necessarily see every upload
176 Also, different versions of dgit
177 (or the software it calls)
178 might import the same .dscs differently
179 (although we try to minimise this).
180 As a consequence, the dgit tracking views of the same
181 suite, made by different instances of dgit, may vary.
182 They will have the same contents, but may have different history.
184 There is no uniform linkage between the tracking branches for
186 The Debian infrastructure
187 does not do any automatic import of uploads made without dgit.
188 It would be possible for a distro's infrastructure to do this;
190 different dgit client instances
191 would see exactly the same history.
193 There has been no bulk import of historical uploads into
194 Debian's dgit infrastructure.
195 To do this it would be necessary to decide whether to
196 import existing vcs history
197 (which might not be faithful to dgit's invariants)
198 or previous non-Dgit uploads
199 (which would not provide a very rich history).
201 git represents only file executability.
202 git does not represent empty directories,
203 or any leaf objects other than plain files and symlinks.
204 The behaviour of Debian source package formats
205 on objects with unusual permissions is complicated.
206 Some pathological Debian source packages will no longer build
207 if empty directories are pruned
208 (or if other things not reproduced by git are changed).
209 Such sources cannot be worked with properly in git,
210 and therefore not with dgit either.
211 .SH READ-ONLY DISTROS
212 Distros which do not maintain a set of dgit history git repositories
213 can still be used in a read-only mode with dgit. Currently Ubuntu
214 is configured this way.
216 git has features which can automatically transform files
217 as they are being copied between the working tree
219 The attributes can be specified in the source tree itself,
222 See \fBgitattributes\fP(5).
224 These transformations are context-sensitive
225 and not, in general, reversible,
226 so dgit operates on the principle that
227 the dgit git history contains the actual contents of the package.
228 (When dgit is manipulating a .dsc,
229 it does so in a private area,
230 where the transforming gitattributes are defused,
233 If transforming gitattributes are used,
234 they can cause trouble,
235 because the working tree files can differ from
236 the git revision history
237 (and therefore from the source packages).
238 dgit warns if it finds a .gitattributes file
239 (in a package being fetched or imported),
240 unless the transforming gitattributes have been defused.
243 and dgit setup-new-tree
244 disable transforming gitattributes
246 by creating a suitable .git/info/attributes.
248 .B dgit setup-new-tree
250 .B dgit setup-gitattributes
252 .SH PACKAGE SOURCE FORMATS
253 If you are not the maintainer, you do not need to worry about the
254 source format of the package. You can just make changes as you like
255 in git. If the package is a `3.0 (quilt)' package, the patch stack
256 will usually not be represented in the git history.
257 .SH FILE EXECUTABILITY
258 Debian source package formats
259 do not always faithfully reproduce
260 changes to executability.
261 But dgit insists that the result of dgit clone is identical
262 (as far as git can represent - see Limitations, above)
263 to the result of dpkg-source -x.
265 So files that are executable in your git tree
266 must be executable in the result of dpkg-source -x
268 If a package has such troublesome files,
269 they have to be non-executable in dgit-compatible git branches.
270 .SH FORMAT 3.0 (QUILT)
271 For a format `3.0 (quilt)' source package, dgit may have to make a
272 commit on your current branch to contain metadata used by quilt and
275 This is because `3.0 (quilt)' source format represents the patch stack
276 as files in debian/patches/ actually inside the source tree. This
277 means that, taking the whole tree (as seen by git or ls) (i)
278 dpkg-source cannot represent certain trees, and (ii) packing up a tree
279 in `3.0 (quilt)' and then unpacking it does not always yield the same
282 dgit will automatically work around this for you when building and
283 pushing. The only thing you need to know is that dgit build, sbuild,
284 etc., may make new commits on your HEAD. If you're not a quilt user
285 this commit won't contain any changes to files you care about.
287 Simply commiting to source files
288 (whether in debian/ or not, but not to patches)
289 will result in a branch that dgit quilt-fixup can linearise.
290 Other kinds of changes,
291 including editing patches or merging,
292 cannot be handled this way.
294 You can explicitly request that dgit do just this fixup, by running
297 If you are a quilt user you need to know that dgit's git trees are
298 `patches applied packaging branches' and do not contain the .pc
299 directory (which is used by quilt to record which patches are
300 applied). If you want to manipulate the patch stack you probably want
301 to be looking at tools like git-dpm.
303 .SS quilt fixup error messages
304 When dgit's quilt fixup fails, it prints messages like this:
307 dgit: base trees orig=5531f03d8456b702eab6 o+d/p=135338e9cc253cc85f84
308 dgit: quilt differences: src: == orig ## gitignores: == orig ##
309 dgit: quilt differences: HEAD ## o+d/p HEAD ## o+d/p
310 starting quiltify (multiple patches, linear mode)
312 dgit: error: quilt fixup cannot be linear. Stopped at:
313 dgit: 696c9bd5..84ae8f96: changed debian/patches/test-gitignore
318 is an import of the .orig tarballs dgit found,
319 with the debian/ directory from your HEAD substituted.
320 This is a git tree object, not a commit:
321 you can pass its hash to git-diff but not git-log.
325 is another tree object,
326 which is the same as orig
327 but with the patches from debian/patches applied.
331 is of course your own git HEAD.
335 shows whether each of the these trees differs from the others
336 (i) in upstream files excluding .gitignore files;
337 (ii) in upstream .gitignore files.
341 indicates inequality.
343 dgit quilt-fixup --quilt=linear walks commits
344 backwards from your HEAD
345 trying to construct a linear set of additional patches,
347 It hopes to eventually find an ancestor
348 whose tree is identical to o+d/p in all upstream files.
350 In the error message,
352 is the first commit child-parent edge
353 which cannot be sensibly be
354 either ignored, or turned into a patch in debian/patches.
355 In this example, this is because
356 it itself changes files in debian/patches,
357 indicating that something unusual is going on
358 and that continuing is not safe.
359 But you might also see other kinds of troublesome commit or edge.
361 Your appropriate response depends on the cause and the context.
362 If you have been freely merging your git branch
363 and do not need need a pretty linear patch queue,
369 .B single-debian-patch
371 .BR dpkg-source(1) .)
372 If you want a pretty linear series,
373 and this message is unexpected,
374 it can mean that you have unwittingly committed changes
375 that are not representable by dpkg-source (such as some mode changes).
376 Or maybe you just forgot a necessary
379 .SH SPLIT VIEW QUILT MODE
380 When working with git branches intended
381 for use with the `3.0 (quilt)' source format
382 dgit can automatically convert a suitable
383 maintainer-provided git branch
384 (in one of a variety of formats)
387 When a split view mode is engaged
388 dgit build commands and
390 will, on each invocation,
391 convert the user's HEAD into the dgit view,
392 so that it can be built and/or uploaded.
394 dgit push in split view mode will push the dgit view to the dgit
396 The dgit view is always a descendant of the maintainer view.
397 dgit push will also make a maintainer view tag
399 and push that to the dgit git server.
401 Split view mode must be enabled explicitly
402 (by the use of the applicable command line options,
403 subcommands, or configuration).
404 This is because it is not possible to reliably tell
406 whether a git tree for a dpkg-source `3.0 (quilt)' package
407 is a patches-applied or patches-unapplied tree.
409 Split view conversions are cached in the ref
410 dgit-intern/quilt-cache.
411 This should not be manipulated directly.
412 .SH FILES IN THE ORIG TARBALL BUT NOT IN GIT - AUTOTOOLS ETC.
413 This section is mainly of interest to maintainers who want to use dgit
414 with their existing git history for the Debian package.
416 Some developers like to have an extra-clean git tree which lacks files
417 which are normally found in source tarballs and therefore in Debian
418 source packages. For example, it is conventional to ship ./configure
419 in the source tarball, but some people prefer not to have it present
420 in the git view of their project.
422 dgit requires that the source package unpacks to exactly the same
423 files as are in the git commit on which dgit push operates. So if you
424 just try to dgit push directly from one of these extra-clean git
425 branches, it will fail.
427 As the maintainer you therefore have the following options:
430 Delete the files from your git branches,
431 and your Debian source packages,
432 and carry the deletion as a delta from upstream.
433 (With `3.0 (quilt)' this means represeting the deletions as patches.
434 You may need to pass --include-removal to dpkg-source --commit,
435 or pass corresponding options to other tools.)
436 This can make the Debian
437 source package less useful for people without Debian build
441 Persuade upstream that the source code in their git history and the
442 source they ship as tarballs should be identical. Of course simply
443 removing the files from the tarball may make the tarball hard for
446 One answer is to commit the (maybe autogenerated)
447 files, perhaps with some simple automation to deal with conflicts and
448 spurious changes. This has the advantage that someone who clones
449 the git repository finds the program just as easy to build as someone
450 who uses the tarball.
452 Of course it may also be that the differences are due to build system
453 bugs, which cause unintended files to end up in the source package.
454 dgit will notice this and complain. You may have to fix these bugs
455 before you can unify your existing git history with dgit's.
457 .SH FILES IN THE SOURCE PACKAGE BUT NOT IN GIT - DOCS, BINARIES ETC.
458 Some upstream tarballs contain build artifacts which upstream expects
459 some users not to want to rebuild (or indeed to find hard to rebuild),
460 but which in Debian we always rebuild.
462 Examples sometimes include crossbuild firmware binaries and
464 To avoid problems when building updated source
466 (in particular, to avoid trying to represent as changes in
467 the source package uninteresting or perhaps unrepresentable changes
469 many maintainers arrange for the package clean target
470 to delete these files.
473 (with any of the commonly used source formats)
474 represent deletion of binaries (outside debian/) present in upstream.
475 Thus deleting such files in a dpkg-source working tree does not
476 actually result in them being deleted from the source package.
478 deleting the files in rules clean sweeps this problem under the rug.
480 However, git does always properly record file deletion.
482 principle is that the dgit git tree is the same of dpkg-source -x,
483 that means that a dgit-compatible git tree always contains these
486 For the non-maintainer,
487 this can be observed in the following suboptimal occurrences:
490 The package clean target often deletes these files, making the git
491 tree dirty trying to build the source package, etc.
494 .BR "dgit -wg" " aka " "--clean=git" ,
495 so that the package clean target is never run.
498 The package build modifies these files, so that builds make the git
500 This can be worked around by using `git reset --hard'
502 (or at least before each commit or push).
504 From the maintainer's point of view,
505 the main consequence is that to make a dgit-compatible git branch
506 it is necessary to commit these files to git.
507 The maintainer has a few additional options for mitigation:
509 it may be possible for the rules file to arrange to do the
510 build in a temporary area, which avoids updating the troublesome
512 they can then be left in the git tree without seeing trouble.
513 .SH PROBLEMS WITH PACKAGE CLEAN TARGETS ETC.
514 A related problem is other unexpected behaviour by a package's
518 modify files which are distributed in the package,
519 or simply forget to remove certain files,
520 dgit will complain that the tree is dirty.
522 Again, the solution is to use
523 .BR "dgit -wg" " aka " "--clean=git" ,
524 which instructs dgit to use git clean instead of the package's
530 This is 100% reliable, but has the downside
531 that if you forget to git add or to commit, and then use
532 .BR "dgit -wg" " or " "git reset --hard" ,
533 your changes may be lost.