Ubuntu Manpage: git-debrebase - tool to maintain series of Debian changes to upstream source

NAME

       git-debrebase - tool to maintain series of Debian changes to upstream source

SYNOPSYS

        git-debrebase [<options...>] [-- <git-rebase options...>]
        git-debrebase [<options...>] <operation> [<operation options...>

QUICK REFERENCE

       These are most of the commands you will regularly need:

        git debrebase -i                           # edit the patch queue
        git debrebase conclude && git push         # push to eg salsa
        git debrebase conclude && dgit push-source # source-only upload
        git debrebase new-upstream 1.2.3-1 [-i]    # uses tag, eg "v1.2.3"
        dpkg-buildpackage -uc -b                   # get test debs, at any time

       To add patches, or edit the packaging, just make git commits.  Ignore anything that may appear in
       debian/patches.  Avoid using "git pull" and "git merge" without "--ff-only".

       When sharing branches, you should usually share a fast-forwarding branch (ie, use "git-debrebase
       conclude" (or "prepush") before pushing.

       git-debrebase has a special branch format, so see "CONVERTING AN EXISTING PACKAGE" in
       dgit-maint-debrebase(7).

GUIDE TO DOCUMENTATION

       This is the command line reference.  There is also a detailed workflow tutorial at
       dgit-maint-debrebase(7) (on which the above "QUICK REFERENCE" is based).  For background, theory of
       operation, and definitions see git-debrebase(5).

       You should read this manpage in conjunction with "TERMINOLOGY" in git-debrebase(5), which defines many
       important terms used here.

PRINCIPAL OPERATIONS

git-debrebase [-- <git-rebase options...>]
git-debrebase [-i <further git-rebase options...>]
Unstitches and launders the branch. (See "UNSTITCHING AND LAUNDERING" below.)

Then, if any git-rebase options were supplied, edits the Debian delta queue, using git-rebase, by
running

git rebase <git-rebase options> <breakwater-tip>

Do not pass a base branch argument: git-debrebase will supply that. Do not use --onto, or
--fork-point. Useful git-rebase options include -i and --autosquash.

If git-rebase stops for any reason, you may git-rebase --abort, --continue, or --skip, as usual. If
you abort the git-rebase, the branch will still have been laundered, but everything in the rebase
will be undone.

The options for git-rebase must either start with "-i", or be prececded by "--", to distinguish them
from options for git-debrebase.

It is hazardous to use plain git-rebase on a git-debrebase branch, because git-rebase has a tendency
to start the rebase too far back in history, and then drop important commits. See "ILLEGAL
OPERATIONS" in git-debrebase(5)

git-debrebase status
Analyses the current branch, both in terms of its contents, and the refs which are relevant to git-
debrebase, and prints a human-readable summary.

Please do not attempt to parse the output; it may be reformatted or reorganised in the future.
Instead, use one of the "UNDERLYING AND SUPPLEMENTARY OPERATIONS" described below.

git-debrebase conclude
Finishes a git-debrebase session, tidying up the branch and making it fast forward again.

Specifically: if the branch is unstitched, launders and restitches it, making a new pseudomerge.
Otherwise, it is an error, unless --noop-ok.

git-debrebase quick
Unconditionally launders and restitches the branch, consuming any ffq-prev and making a new
pseudomerge.

If the branch is already laundered and stitched, does nothing.

git-debrebase prepush [--prose=<for commit message>]
If the branch is unstitched, stitches it, consuming ffq-prev.

This is a good command to run before pushing to a git server. You should consider using conclude
instead, because that launders the branch too.

git-debrebase stitch [--prose=<for commit message>]
Stitches the branch, consuming ffq-prev.

If there is no ffq-prev, it is an error, unless --noop-ok.

You should consider using prepush or conclude instead.

git-debrebase scrap
Throws away all the work since the branch was last stitched. This is done by resetting you to ffq-
prev and discarding all working tree changes.

If you are in the middle of a git-rebase, will abort that too.

git-debrebase new-upstream <new-version> [<upstream-details>...] [--|-i <git-rebase options...>]
Rebases the delta queue onto a new upstream version. In detail:

Firstly, checks that the proposed rebase seems to make sense: It is a snag unless the new upstream(s)
are fast forward from the previous upstream(s) as found in the current breakwater anchor. And, in
the case of a multi-piece upstream (a multi-component upstream, in dpkg-source terminology), if the
pieces are not in the same order, with the same names.

If all seems well, unstitches and launders the branch.

Then, generates (in a private working area) a new anchor merge commit, on top of the breakwater tip,
and on top of that a commit to update the version number in debian/changelog.

Finally, starts a git-rebase of the delta queue onto these new commits.

That git-rebase may complete successfully, or it may require your assistance, just like a normal git-
rebase.

If you git-rebase --abort, the whole new upstream operation is aborted, except for the laundering.

<new-version> may be a whole new Debian version, including revision, or just the upstream part, in
which case -1 will be appended to make the new Debian version.

The <upstream-details> are, optionally, in order:

<upstream-commit-ish>
The new upstream branch (or commit-ish). The default is to look for one of these tags, in this
order: U vU upstream/U; where U is the new upstream version. (This is the same algorithm as
git-deborig(1).)

It is a snag if the upstream contains a debian/ directory; if forced to proceed, git-debrebase
will disregard the upstream's debian/ and take (only) the packaging from the current breakwater.

<piece-name> <piece-upstream-commit-ish>
Specifies that this is a multi-piece upstream. May be repeated.

When such a pair is specified, git-debrebase will first combine the pieces of the upstream
together, and then use the result as the combined new upstream.

For each <piece-name>, the tree of the <piece-upstream-commit-ish> becomes the subdirectory
<piece-name> in the combined new upstream (supplanting any subdirectory that might be there in
the main upstream branch).

<piece-name> has a restricted syntax: it may contain only ASCII alphanumerics and hyphens.

The combined upstream is itself recorded as a commit, with each of the upstream pieces' commits
as parents. The combined commit contains an annotation to allow a future git-debrebase new
upstream operation to make the coherency checks described above.

<git-rebase options>
These will be passed to git rebase.

If the upstream rebase is troublesome, -i may be helpful. As with plain git-debrebase, do not
specify a base, or --onto, or --fork-point.

If you are planning to generate a .dsc, you will also need to have, or generate, actual orig
tarball(s), which must be identical to the rev-spec(s) passed to git-debrebase. git-debrebase does
not concern itself with source packages so neither helps with this, nor checks it. git-deborig(1),
git-archive(1), dgit(1) and gbp-import-orig(1) may be able to help.

git-debrebase make-patches [--quiet-would-amend]
Generate patches in debian/patches/ representing the changes made to upstream files.

It is not normally necessary to run this command explicitly. When uploading to Debian, dgit and git-
debrebase will cooperate to regenerate patches as necessary. When working with pure git remotes, the
patches are not needed.

Normally git-debrebase make-patches will require a laundered branch. (A laundered branch does not
contain any patches.) But if there are already some patches made by git-debrebase make-patches, and
all that has happened is that more changes to upstream files have been committed, running it again
can add the missing patches.

If the patches implied by the current branch are not a simple superset of those already in
debian/patches, make-patches will fail with exit status 7, and an error message. (The message can be
suppressed with --quiet-would-amend.) If the problem is simply that the existing patches were not
made by git-debrebase, using dgit quilt-fixup instead should succeed.

git-debrebase convert-from-unapplied [<upstream-commit-ish>]
git-debrebase convert-from-gbp [<upstream-commit-ish>]
Converts any of the following into a git-debrebase interchange branch:

• a gbp patches-unapplied branch (but not a gbp pq patch-queue branch)

• a patches-unapplied git packaging branch containing debian/patches, as used with quilt

• a git branch for a package which has no Debian delta - ie where upstream files are have not been
modified in Debian, so there are no patches

(These two commands operate identically and are simply aliases.)

The conversion is done by generating a new anchor merge, converting any quilt patches as a delta
queue, and dropping the patches from the tree.

The upstream commit-ish should correspond to the upstream branch or tag, if there is one. It is a
snag if it is not an ancestor of HEAD, or if the history between the upstream and HEAD contains
commits which make changes to upstream files. If it is not specified, the same algorithm is used as
for git-debrebase new-upstream.

It is also a snag if the specified upstream has a debian/ subdirectory. This check exists to detect
certain likely user errors, but if this situation is true and expected, forcing it is fine.

git-debrebase will try to look for the dgit archive view of the most recent release, and if it finds
it will make a pseduomerge so that your new git-debrebase view is appropriately fast forward.

The result is a well-formed git-debrebase interchange branch. The result is also fast-forward from
the original branch.

It is a snag if the new branch looks like it will have diverged, just as for a laundering/unstitching
call to git-debrebase; See "Establish the current branch's ffq-prev", below.

Note that it is dangerous not to know whether you are dealing with a (gbp) patches-unapplied branch
containing quilt patches, or a git-debrebase interchange branch. At worst, using the wrong tool for
the branch format might result in a dropped patch queue!

UNDERLYING AND SUPPLEMENTARY OPERATIONS

git-debrebase breakwater
Prints the breakwater tip commitid. If your HEAD branch is not fully laundered, prints the tip of
the so-far-laundered breakwater.

git-debrebase anchor
Prints the breakwater anchor commitid.

git-debrebase analyse
Walks the history of the current branch, most recent commit first, back until the most recent anchor,
printing the commit object id, and commit type and info (ie the semantics in the git-debrebase model)
for each commit.

git-debrebase record-ffq-prev
Establishes the current branch's ffq-prev, as discussed in "UNSTITCHING AND LAUNDERING", but does not
launder the branch or move HEAD.

It is an error if the ffq-prev could not be recorded. It is also an error if an ffq-prev has already
been recorded, unless --noop-ok.

git-debrebase convert-to-gbp
Converts a laundered branch into a gbp patches-unapplied branch containing quilt patches. The result
is not fast forward from the interchange branch, and any ffq-prev is deleted.

This is provided mostly for the test suite and for unusual situations. It should only be used with
care and with a proper understanding of the underlying theory.

Be sure to not accidentally treat the result as a git-debrebase branch, or you will drop all the
patches!

git-debrebase convert-from-dgit-view [<convert-options>] [upstream]
Converts any dgit-compatible git branch corresponding to a (possibly hypothetical) 3.0 quilt dsc
source package into a git-debrebase-compatible branch.

This operation should not be used if the branch is already in git-debrebase form. Normally git-
debrebase will refuse to continue in this case (or silently do nothing if the global --noop-ok option
is used).

Some representation of the original upstream source code will be needed. If upstream is supplied,
that must be a suitable upstream commit. By default, git-debrebase will look first for git tags (as
for new-upstream), and then for orig tarballs which it will ask dgit to process.

The upstream source must be exactly right and all the patches in debian/patches must be up to date.
Applying the patches from debian/patches to the upstream source must result in exactly your HEAD.

The output is laundered and stitched. The resulting history is not particularly pretty, especially
if orig tarball(s) were imported to produce a synthetic upstream commit.

The available convert-options are as follows. (These must come after convert-from-dgit-view.)

--[no-]diagnose
Print additional error messages to help diagnose failure to find an appropriate upstream.
--no-diagnose is the default.

--build-products-dir
Directory to look in for orig tarballs. The default is the git config option
dgit.default.build-products-dir or failing that, "..". Passed on to dgit, if git-debrebase
invokes dgit.

--[no-]origs
Whether to try to look for or use any orig tarballs. --origs is the default.

--[no-]tags
Whether to try to look for or use any upstream git tags. --tags is the default.

--always-convert-anyway
Perform the conversion operation, producing unpleasant extra history, even if the branch seems to
be in git-debrebase form already. This should not be done unless necessary, and it should not be
necessary.

git-debrebase forget-was-ever-debrebase
Deletes the ffq-prev and debrebase-last refs associated with this branch, that git-debrebase and dgit
use to determine whether this branch is managed by git-debrebase, and what previous head may need to
be stitched back in.

This can be useful if you were just playing with git-debrebase, and have used git-reset --hard to go
back to a commit before your experiments.

Do not use this if you expect to run git-debrebase on the branch again.

OPTIONS

       This  section  documents the general options to git-debrebase (ie, the ones which immediately follow git-
       debrebase or git debrebase on the command line).  Individual operations may have their own options  which
       are docuented under each operation.

       -f<snag-id>
           Turns snag(s) with id <snag-id> into warnings.

           Some  troublesome  things  which  git-debrebase  encounters  are  snags.  (The specific instances are
           discussed in the text for the relevant operation.)

           When a snag is detected, a message is  printed  to  stderr  containing  the  snag  id  (in  the  form
           "-f<snag-id>"), along with some prose.

           If snags are detected, git-debrebase does not continue, unless the relevant -f<snag-id> is specified,
           or --force is specified.

       --force
           Turns all snags into warnings.  See the -f<snag-id> option.

           Do  not  invoke  git-debrebase  --force  in  scripts  and  aliases;  instead,  specify the particular
           -f<snag-id> for expected snags.

       --noop-ok
           Suppresses the error in some situations where git-debrebase does nothing, because there is nothing to
           do.

           The specific instances are discussed in the text for the relvant operation.

       --anchor=<commit-ish>
           Treats <commit-ish> as an anchor.  This overrides the  usual  logic  which  automatically  classifies
           commits as anchors, pseudomerges, delta queue commits, etc.

           It also disables some coherency checks which depend on metadata extracted from its commit message, so
           it  is a snag ("-fanchor-treated") if <commit-ish> is the anchor for the previous upstream version in
           git-debrebase new-upstream operations.  You have to check yourself that  the  new  upstream  is  fast
           forward from the old one, and has the right components (as if applicable).

       --dgit=<program>
           Run  <program>,  instead  of  dgit from PATH, when invocation of dgit is necessary.  This is provided
           mostly for the benefit of the test suite.

       -D  Requests (more) debugging.  May be repeated.

       --experimental-merge-resolution
           Enable experimental code for handling general merges (see "General merges" in git-debrebase(5)).

           If using this option succeeds, the output is likely to be correct, although it would be a  good  idea
           to check that it seems sane.

           If it fails, your tree should be left where it was.

           However,  there  may be lossage of various kinds, including misleading error messages, and references
           to  nonexistent  documentation.   On  merge  failure,  it  might  invite  you  to   delve   into   an
           incomprehensible  pile  of  multidimensional  merge wreckage, which is supposed to be left in special
           refs invented for the purpose (so, not your working tree, or HEAD).

UNSTITCHING AND LAUNDERING

Several operations unstitch and launder the branch first. In detail this means:

Establish the current branch's ffq-prev
If ffq-prev is not yet recorded, git-debrebase checks that the current branch is ahead of relevant remote
tracking branches. The relevant branches depend on the current branch (and its git configuration) and
are as follows:

• The branch that git would merge from (remote.<branch>.merge, remote.<branch>.remote);

• The branch git would push to, if different (remote.<branch>.pushRemote etc.);

• For local dgit suite branches, the corresponding tracking remote;

• If you are on "master", remotes/dgit/dgit/sid.

The apparently relevant ref names to check are filtered through branch.<branch>.ffq-ffrefs, which is a
semicolon-separated list of glob patterns, each optionally preceded by !; first match wins.

In each case it is a snag if the local HEAD is behind the checked remote, or if local HEAD has diverged
from it. All the checks are done locally using the remote tracking refs: git-debrebase does not fetch
anything from anywhere.

If these checks pass, or are forced, git-debrebse then records the current tip as ffq-prev.

Examine the branch
git-debrebase analyses the current HEAD's history to find the anchor in its breakwater, and the most
recent breakwater tip.

Rewrite the commits into laundered form
Mixed debian+upstream commits are split into two commits each. Delta queue (upstream files) commits
bubble to the top. Pseudomerges, and quilt patch additions, are dropped.

This rewrite will always succeed, by construction. The result is the laundered branch.