Title: Clarifying policies and workflows for Non Maintainer Uploads (NMUs)
State: DRAFT
Date: 2008-02-12
Drivers: Lucas Nussbaum <lucas@debian.org>,
 Bas Wijnen <wijnen@debian.org>
URL: http://wiki.debian.org/NmuDep
 This document aims at clarifying the policies and workflows used for NMUs
 inside Debian. Its main goal is to provide a patch to section 5.11 of the
 Debian Developer's Reference, adressing the current issues regarding NMUs.

Introduction and Motivation

In Debian, each package is "owned" by its maintainer, or by a small group of maintainers, in the case of team maintenance. Modifying the package requires going through those developers, which sometimes add a long, unnecessary delay, especially in the case of inactive or busy maintainers.

Non-maintainer uploads (NMUs) alleviate this problem, by allowing any developer to upload a new version of another maintainer's package. However, the current rules for NMUs are not very clear, so:

  1. many developers prefer not to do NMUs.
  2. different developers understand the rules differently, leading to different opinions on what's allowed or not.
  3. NMUs are often received with angry comments from maintainers.

This Debian Enhancement Proposal has two goals:

  1. improve section 5.11 of the Developer's Reference, to clarify it and address the current issues about NMUs
  2. improve related tools, like the nmudiff script in the devscripts package.

Proposed section 5.11: Non-Maintainer Uploads (NMUs)

Every package has one or more maintainers. Normally, these are the people who work on and upload new versions of the package. In some situations, it is useful that other developers can upload a new version as well, for example if they want to fix a bug in a package they don't maintain. Such uploads are called Non-Maintainer Uploads (NMU).

NMUs usually happens when someone wants to fix a bug NMUs can happen for various reasons, the most usual one being to fix bugs. There are some rules to follow when doing an NMU. These are explained below. An NMU is allowed for any reason, as long as those rules are followed.

5.11.1 How to do an NMU

There are no strict rules for NMUs, because there are many different situations. However, before doing an NMU, consider the following questions:

In most cases, the above questions should not make you reconsider doing an NMU. Fixing bugs is what really matters. But maybe, delaying the NMU some more might be a good idea.

Here are some example of generally accepted behaviours: NMUs and debian/changelog

Just like any other (source) upload, NMUs must add an entry to debian/changelog, telling what has changed with this upload. The first line of this entry is special, it must be

For non-native packages, the version of the changelog entry must be the upstream version, plus a Debian revision, just as in a normal upload. However, the debian revision should be of the form x.y, where x is one less than the next to be released normal Debian revision number for this upstream version, and y is a counter starting at 1. For example, if the current version is 1.5-3, then an NMU would get 1.5-3.1 for the version. If a new upstream version is packaged in the NMU, the version would become 1.6-0.1.

FIXME: Add something about native package NMU versioning. See bug #437392. Using the DELAYED/ queue

When an NMU is done without contact with the maintainer first, there are several ways to allow the maintainer to do things differently. First of all, if the bug that is fixed has not had any activity for 7 days, and there is no indication that it is being worked on, NMUs are allowed without any delay (as long as they follow the other rules). In some situations, such as bug squashing parties, it is not desirable to have to wait 7 days and do the upload after that. It is then possible to schedule an upload for some time in the future. That way, the maintainer has some time to fix it differently (and cancel the upload). But when nothing is done (because the maintainer agrees with the upload, or is unavailable), the upload happens at the scheduled time without any action from the NMUer.

FIXME: explain how to use the DELAYED/ queue. Relaxed NMU policy

FIXME: describe what they are, and how to apply them. We should have a list of things to consider when deciding between DELAYED/2,7,etc...)

5.11.2 NMUs, from the maintainer point of view

When someone NMUs your package, this means they want to help you to keep it in good shape. This saves you work, and gives users fixed packages faster. You can consider asking the NMUer to become a co-maintainer of the package.

If someone suggests that they could do an NMU on your package, you should be thankful that they want to put time into this, while it is really your responsibility to fix the bug. Receiving an NMU on a package is not a bad thing; it just means that the package is interesting enough for other people to work on it.

When a package has been NMUed, the maintainer should acknowledge it in the next upload. This makes clear that the changes were accepted in the maintainer's packaging, and that they aren't lost again. For this, you must first incorporate the changes into your packaging, by applying the patch that was sent. When uploading, you should use the -v option of dpkg-buildpackage, so that the NMU's changelog entry is also copied to the .changes file that is generated. This is important to allow the BTS version tracking to work.

FIXME: describe how the BTS reacts to NMUs.

5.11.3 Source NMUs vs Binary-only NMUs (binNMUs)

FIXME: explain the difference.

5.11.4 NMUs vs QA uploads

NMUs are uploads of packages which are owned by another maintainer. There is another type of uploading a package which is not yours: a QA upload. This is an upload of an orphaned package.

QA uploads are very much like normal maintainer uploads: they may fix anything, even minor issues; the version numbering is normal, and there is no need to use a delayed upload. The difference is that you are not listed as the Maintainer or Uploader for the package. Also, the changelog entry of a QA upload has a special first line:

If you want to do an NMU, and it seems the maintainer is not active, it is wise to check if the package is orphaned. When doing the first QA upload to an orphaned package, the maintainer should be set to Debian QA Group < packages@qa.debian.org >. Orphaned packages which did not have a QA upload yet still have their old maintainer set. There is a list of them at http://qa.debian.org/orphaned.html.

nmudiff improvements

FIXME: propose new wording for the default template to make it more friendly