NAME

       dgit - tips for maintaining official Debian backports

INTRODUCTION

       This document describes elements of a workflow for using dgit to maintain an official
       Debian backport.  We do not assume that whoever uploads the package to Debian unstable is
       using dgit.

GENERAL TIPS

       The first time a package is backported for any particular Debian release, you will have to
       pass the --new option to dgit.

TERMINOLOGY

       Let the master branch contain the packaging history uploaded to Debian unstable, and the
       buster-bpo branch be where you prepare your uploads to the buster-backports suite.

       A merging backports workflow means that each time an upload migrates to Debian testing and
       you want to prepare an upload to buster-backports, you do something like this:

           % git checkout buster-bpo
           % git merge master
           % dch --bpo
           % # any other changes needed for backporting
           % git commit -a
           % # try a build

       A rebasing backports workflow means that you throw away the history of the buster-bpo
       branch each time a new version migrates to Debian testing, something equivalent to this:

           % git checkout -B buster-bpo master
           % dch --bpo
           % # any other changes needed for backporting
           % git commit -a
           % # try a build

       If you use a merging backports workflow, your changelog contains entries for each previous
       upload to buster-backports; in a rebasing workflow, it contains only the latest.

CHOOSING BETWEEN THE TWO WORKFLOWS

       If backporting involves making no (additional) changes to the upstream source, whether you
       use a merging or rebasing backports workflow is a matter of personal preference.  There
       are good arguments in favour of both workflows fitting the semantics of the *-backports
       suites.

       If you have to make changes to the upstream source to make the package work on machines
       running Debian stable, it is advisable to choose a rebasing workflow.  This ensures that
       dgit can automatically update the debian/patches directory without any manual
       intervention.

TIPS FOR A MERGING WORKFLOW

   Use dgit's branches
       If you do not yourself upload the package to Debian unstable, it is usually easiest to use
       dgit's branches, and ignore the configured Vcs-Git repository.

       You would use

           % dgit clone foo bullseye

       for a new backport of package 'foo' to buster-backports, and then

           % dgit fetch bullseye
           % git merge dgit/dgit/bullseye

       when new versions migrate to Debian testing.

TIPS FOR A REBASING WORKFLOW

   Use dgit's branches
       If you do not yourself upload the package to Debian unstable, it is usually easiest to use
       dgit's branches, and ignore the configured Vcs-Git repository.  For each new version from
       Debian testing, you would

           % dgit fetch bullseye
           % git checkout -B buster-bpo dgit/dgit/bullseye
           % # use git-cherry-pick(1) to (re)apply any needed backporting fixes

   Overwriting
       dgit push tries hard to prevent you from accidentally overwriting uploads that it thinks
       aren't represented in the git history you are trying to upload.  This is mainly to prevent
       accidentally overwriting NMUs.

       With a rebasing backports workflow, dgit will think that every upload of a new version
       from Debian testing might be accidentally overwriting uploads.  You will need to
       explicitly indicate the upload to buster-backports you wish to overwrite.

       Suppose that the last upload to buster-backports was versioned 1.2.2-1~bpo10+1 and you
       have now prepared 1.2.3-1~bpo10+1 for upload.  When you dgit push, you will need to pass
       --overwrite=1.2.2-1~bpo10+1.

       Alternatively, you can perform the pseudomerge that --overwrite would have done yourself:

           % dgit fetch buster-backports
           % git merge -s ours dgit/dgit/buster-backports
           % dgit push-source

SEE ALSO

       dgit(1), dgit(7), https://backports.debian.org/

AUTHOR

       This manpage was written and is maintained by Sean Whitton <spwhitton@spwhitton.name>.