# Introduction

Welcome to &gbp;, a system that integrates the Debian package build system with Git. The current version of this manual can be found here.

What can these tools do for you:

- Import an existing &debian; package into &git;

- Import new upstream versions, NMUs etc. with optional filters

- Automatic upstream tarball generation

- Maintain a consistent branch and tag naming across repositories or across a team of developers

- Automatically sign tags

- Automatically push changes to remote repositories

- Make sure you have committed all changes to the right branch before releasing

- Export to a clean build area before building

- Automatic debian/changelog generation

- Automatic generation of snapshot releases for local testing

- Simple patch management

All of this is (hopefully) being done without restricting the user to certain usage patterns.

## Repository Layout and Terminology

It is recommended to have the &debian; packaging on a separate branch than the upstream source

this, of course, has no meaning for &debian; native packages

. This is necessary to be able to import and merge in new upstream versions via &gbp-import-orig;. To distinguish these two branches, the following terminology

corresponding to the command line and config file options

is used:

- The `debian-branch` (the default branch name used in the &git; repository is master) holds your current development work. That's the branch you usually cut your releases from and the default branch new upstream releases are merged onto.

- The `upstream-branch` (the default branch name used in the &git; repository is upstream) holds the upstream releases. This can either be a branch you import to or a branch of an upstream repository you pull from.

- The `pristine-tar branch` (the default branch name used in the &git; repository is pristine-tar) holds the necessary additional information to recreate the original tarball from the `upstream-branch`. In order to use this feature, you need to install the &pristine-tar; package.

- There can be one or more `patch-queue branches`. Every patch-queue branch is related to a `debian-branch`. If the `debian-branch` is called master, the corresponding patch-queue branch is called patch-queue/master. The patch-queue branch is the &debian; branch plus the contents of debian/patches applied. These branches are managed with &gbp-pq;.

You're completely free to pick any repository layout; the branch names above are only &gbp;'s defaults. They can be changed at any point in time, and you can work with an arbitrary number of branches. For example, branches like nmu, backports or stable might (temporarily or permanently) become your `debian-branch`, and branches like dfsg or snapshots might become your `upstream-branch`—it doesn't matter if these branches are maintained with &gbp-import-orig; or not.

A recommended branch layout is described in gbp.branch.naming.

Since &gbp-buildpackage; only works with local &git;-repositories, you have to use `git push` in order to publish your changes to remote repositories like git.debian.org; this can also be automatized with &gbp-buildpackage;'s `post-tag` hook.

## Workflow

A typical, simple workflow consists of the following steps:

1. Import a new &debian; package via &gbp-import-dsc;. This imports the &debian; Package on the `debian-branch` and the upstream sources on the `upstream-branch`.

2. Develop, test, commit changes. During this time, you can always build the package with &gbp-buildpackage;. In case you have uncommitted changes in your source tree, you can use the `--git-ignore-new` option.

3. Optionally you can create the &debian; changelog entries using &gbp-dch; and create snapshot releases for testing using its `--snapshot` option.

4. Once satisfied, you can build the final package with &gbp-buildpackage; `--git-tag`. This additionally creates a tag within &git; so you can switch back to that version later at any time. The format of the tags can be specified; tags can be &gpg; signed.

5. When a new upstream version is released and upstream isn't using &git;, you can import the new version via &gbp-import-orig; onto the `upstream-branch`. &gbp-import-orig; will by default try to merge the new upstream version onto the `debian-branch`. You can skip the merge with `--no-merge`. After resolving any potential conflicts, go back to the second step.

These steps will be explained in more details in the following sections.