which can worked on with rebase,
and also shared.
+=head2 DISCUSSION
+
git-debrebase is designed to work well with dgit.
git-debrebase can also be used in workflows without source packages,
for example to work on Debian-format packages outside or alongside Debian.
to work on packages inherited from Debian,
because it assumes that you want to throw away any packaging
provided by your upstream.
-However, of git-debrebase in Debian does not make anything harder for
+However, use of git-debrebase in Debian does not make anything harder for
derivatives, and it can make some things easier.
+When using gitk on branches managed by git-debrebase,
+B<gitk --date-order>, B<gitk --first-parent>
+and B<gitk -- :.> (or B<gitk .>)
+produce more useful output than the default.
+
=head1 TERMINOLOGY
=over
=item Pseudomerge
A merge which does not actually merge the trees;
-instead, it takes its tree, by construction, from only one parent.
+instead, it is constructed by taking the tree
+from one of the parents
+(ignoring the contents of the other parents).
These are used to make a rewritten history fast forward
from a previous tip,
so that it can be pushed and pulled normally.
Files in B<debian/patches/> generated for the benefit of
dpkg-source's 3.0 (quilt) .dsc source package format.
-Not used, often deleted, and regenerated when needed,
+Not used, often deleted, and regenerated when needed
+(such as when uploading to Debian),
by git-debrebase.
+=item Interchange branch; breakwater; stitched; laundered
+
+See L</BRANCHES AND BRANCH STATES - OVERVIEW>.
+
+=item Anchor; Packaging
+
+See L</BRANCH CONTENTS - DETAILED SPECIFICATION>.
+
+=item ffq-prev; debrebase-last
+
+See L</STITCHING, PSEUDO-MERGES, FFQ RECORD>.
+
=back
=head1 DIAGRAM
1 1 1 breakwater branch, merging baseline
/ / / unmodified upstream code
---@-----@--A----@--B--C plus debian/ (but no debian/patches)
- / / / no ref refers to this: we
+ / / / no ref refers to this: we
--#-----#-------#-----> upstream reconstruct its identity by
- inspecting interchange branch
+ inspecting interchange branch
Key:
1,2,3 commits touching upstream files only
-/- pseudomerge; contents are identical to
/ parent lower on diagram.
- % dgit-generated commit of debian/patches.
+ % dgit- or git-debrebase- generated commit of debian/patches.
`3.0 (quilt)' only; generally dropped by git-debrebase.
* Maintainer's HEAD was here while they were editing,
B<breakwater>.
The breakwater contains unmodified upstream source,
but with Debian's packaging superimposed
-(replacing any C<debian/> directory that may be in upstream).
+(replacing any C<debian/> directory that may be in
+the upstream commits).
The breakwater does not contain any representation of
the delta queue (not even debian/patches).
The part of the breakwater processed by git-debrebase
While a branch is unstitched,
it is not in interchange format.
The previous interchange branch tip
-tip is recorded,
+is recorded,
so that the previous history
and the user's work
can later be
An B<anchor> commit,
which is usually a special two-parent merge:
-The first parent is
-a previous branch tip with Debian packaging tip
-(perhaps a previous breakwater tip)
-whose upstream files are irrelevant,
-and whose packaging files are identical to the anchor's.
-The second parent is an upstream source commit,
-whose packaging files (if any) are irrelevant,
-and whose upstream files are identical to the anchor's.
+
+The first parent
+contains the most recent version, at that point,
+of the Debian packaging (in debian/);
+it also often contains upstream files,
+but they are to be ignored.
+Often the first parent is a previous breakwater tip.
+
+The second parent
+is an upstream source commit.
+It may sometimes contain a debian/ subdirectory,
+but if so that is to be ignored.
+The second parent's upstream files
+are identical to the anchor's.
Anchor merges always contain
C<[git-debrebase anchor: ...]>
as a line in the commit message.
+
Alternatively,
an anchor may be a single-parent commit which introduces
the C<debian/> directory and makes no other changes:
parent is not examined.
If the two parents have identical trees,
-the contributing parent is taken to be
-the one with the later commit date,
-or if the commit dates are the same,
-the first parent.
-
-=item dgit dsc import
-
-Debian .dsc source package import(s) made by dgit.
-Each such import must be a two-parent pseudomerge
-whose contributing parent is in the special
-dgit format (not described further here).
-The overwritten parent must be
-the previous interchange tip.
-This is the form normally generated by dgit
-when it imports .dsc-based uploads.
+the one with the later commit date
+(or, if the commit dates are the same,
+the first parent)
+is treated as
+the contributing parent.
+
+=item dgit dsc import pseudomerge
+
+Debian .dsc source package import(s)
+made by dgit
+(during dgit fetch of a package most recently
+uploaded to Debian without dgit,
+or during dgit import-dsc).
+
+git-debrebase requires that
+each such import is in the fast-forwarding
+format produced by dgit:
+a two-parent pseudomerge,
+whose contributing parent is in the
+non-fast-forwarding
+dgit dsc import format (not described further here),
+and whose overwritten parent is
+the previous interchange tip
+(eg, the previous tip of the dgit suite branch).
=back
For this reason the tools will try to help the user
avoid divergence of the interchange branch.
-See dgit-maint-rebase(7) XXX TBD
-for a discussio of what kinds of behaviours
+See dgit-maint-rebase(7)
+for a discussion of what kinds of behaviours
should be be avoided
because
they might generate such merges.
in principle tolerable,
but each of the parents would have to be, in turn,
a breakwater,
-and difficult qeustions arise if they don't have the same anchor.
+and difficult questions arise if they don't have the same anchor.
We use the commit message annotation to
distinguish the special anchor merges from other general merges,
=back
+=head1 ILLEGAL OPERATIONS
+
+Some git operations are not permitted in this data model.
+Performing them will break git-debrebase.
+
+=over
+
+=item General merges
+
+See L</OTHER MERGES>, above.
+
+=item git-rebase starting too soon, or without base argument
+
+git-rebase must not be invoked in such a way that
+the chosen base is before the anchor,
+or before the last pseudomerge.
+This is because git-rebase mangles merges.
+git rebase --preserve-merges is also dangerous.
+
+git-rebase without a base argument will often start too early.
+
+For these reasons,
+it is better to use git-debrebase and
+let it choose the base
+for your rebase.
+If you do realise you have make this mistake,
+it is best to use the reflog to recover to a suitable
+good previous state.
+
+=item Editing debian/patches
+
+debian/patches is an output from git-debrebase,
+not an input.
+If you edit patches git-debrebase will complain
+and refuse to work.
+If you add patches your work is likely to be discarded.
+
+Instead of editing patches,
+use git-debrebase to edit the corresponding commits.
+
+=back
+
=head1 COMMIT MESSAGE ANNOTATIONS
git-debrebase makes annotations
[git-debrebase[ COMMIT-TYPE [ ARGS...]]: PROSE, MORE PROSE]
-git-debrebase does not pay attention to anything after the colon,
-so PROSE is ignored.
+git-debrebase treats anything after the colon as a comment,
+paying no attention to PROSE.
The full set of annotations is:
[git-debrebase: split mixed commit, debian part]
[git-debrebase upstream-combine . PIECE[ PIECE...]: new upstream]
[git-debrebase anchor: new upstream NEW-UPSTREAM-VERSION, merge]
[git-debrebase: new upstream NEW-UPSTREAM-VERSION, changelog]
+ [git-debrebase: export and commit patches]
[git-debrebase convert-from-gbp: drop patches]
[git-debrebase anchor: declare upstream]
Only anchor merges have the C<[git-debrebase anchor: ...]> tag.
Single-parent anchors are not generated by git-debrebase,
-and when made manually should not be tagged.
+and when made manually should not
+contain any C<[git-debrebase ...]> annotation.
The C<split mixed commit> and C<convert dgit import>
tags are added to the pre-existing commit message,
=head1 APPENDIX - DGIT IMPORT HANDLING
+The dgit .dsc import format is not documented or specified
+(so some of the following terms are not defined anywhere).
+The dgit import format it is defined by the implementation in dgit,
+of which git-debrebase has special knowledge.
+
Consider a non-dgit NMU followed by a dgit NMU:
- interchange --/--B3!--%--/----D*-->
+ interchange --/--B3!--%--//----D*-->
/ /
% 4
/ 3
1 0 00 =XBC%
/
/
- --@--A breakwater
- /
- --#--------> upstream
+ --@--A breakwater
+ /
+ --#--------> upstream
Supplementary key:
=XBC% dgit tarball import of .debian.tar.gz containing
- Debian packaging including changes B C and quilt patches
-
+ Debian packaging including changes B C and quilt patches
0 dgit tarball import of upstream tarball
- 00 dgit tarball import of supplementary upstream tarball
- &_ dgit nearly-breakwater import
+ 00 dgit tarball import of supplementary upstream piece
+ &_ dgit import nearly-breakwater-anchor
+ // dgit fetch / import-dsc pseudomerge to make fast forward
+
&' git-debrebase converted import (upstream files only)
- D' git-debrebase converted debian/ changes import
+ C' git-debrebase converted packaging change import
* ** before and after HEAD
=item I. No new upstream version
(0 + 00 eq #)
- --/--B3!--%--/------D*-------------/-->
- / / /
- % 4 4**
- / 3 3
- / 2 2
- / 1 1
- 2 &_ /
- / /| \ /
+ --/--B3!--%--//-----D*-------------/-->
+ / / /
+ % 4 4**
+ / 3 3
+ / 2 2
+ / 1 1
+ 2 &_ /
+ / /| \ /
1 0 00 =XBC% /
- / /
- / /
- --@--A-----B-----------------------C--D
- /
- --#----------------------------------------->
+ / /
+ / /
+ --@--A-----B---------------------C'---D
+ /
+ --#----------------------------------------->
=item II. New upstream
(0 + 00 neq #)
- --/--B3!--%--/------D*-------------/-->
- / / /
- % 4 4**
- / 3 3
- / 2 2
- / 1 1
- 2 &_ /
- / /| \ /
+ --/--B3!--%--//-----D*-------------/-->
+ / / /
+ % 4 4**
+ / 3 3
+ / 2 2
+ / 1 1
+ 2 &_ /
+ / /| \ /
1 0 00 =XBC% /
- / /
- / /
- --@--A-----B--------------------@--C--D
- / /
- --#----------------------- - - / - - ----->
- /
- &'
- /|
- 0 00
+ / /
+ / /
+ --@--A-----B-----------------@---C'---D
+ / /
+ --#--------------------- - - / - - --------->
+ /
+ &'
+ /|
+ 0 00
=back
~ianmdlvl / dgit.git / blobdiff