A secondary package manager is a package manager that instead of
directly aiming
at replacing portage as primary package manager.
What does it do instead?
The first restriction is that no packages in the tree must rely on
the secondary
package manager. While packages may provide a level of support
(while being
compatible with the primary package manager) this may not
result in a
significant increase of features.
Why can a certain ebuild not DEPEND specifically on a third party package manager? I think you raise some good points in this email, however I think the overall aim is flawed. The package manager should be just as switching as the compiler, the libc, the baselayout, or the kernel. None of these require anywhere near as many hoops to jump through to be supported in gentoo, and they all have their own fixes that need to be made. No changes should be made to the tree which directly impedes the ability of the "primary package manager" to do its job, but at the same time, no changes should be made which impede other package managers from outperforming the "primary package manager". Forcing package managers to stay even with all of portages ideosyncrocies is just holding back new package managers from making progress. On 5/20/06, Paul de Vrieze <[EMAIL PROTECTED]> wrote:
The promissed glep on package manager requirements. Please comment on it. There are some parts that may be controversial (portage has in the past not provided support for reverting to stable either), but please keep the discussion on topic. Paul -- Paul de Vrieze Gentoo Developer Mail: [EMAIL PROTECTED] Homepage: http://www.devrieze.net GLEP: 49 Title: Alternative Package Manager requirements Version: $Revision: 2214 $ Last-Modified: $Date: 2006-05-20 14:51:41 +0200 (Sat, 20 May 2006) $ Author: Paul de Vrieze <[EMAIL PROTECTED]>, Status: Draft Type: Standards Track Content-Type: text/x-rst Created: 18-May-2006 Post-History: 19-May-2006 Abstract ======== This GLEP describes four classes of package managers. What the requirements for them are, and what support they can receive. Motivation ========== To set a standard that package managers that seek gentoo project approval and support should adhere to. Rationale ========= Currently portage is showing its age. The code of portage does not seem to be salvageable for new versions. There are two known alternative package managers that claim a level of portage compatibility. These alternatives are `paludis`_ and `pkgcore`_. Before these alternatives are developed further, a set of rules should be created to level the playing field and ensuring that decisions can be made clearly. Backwards Compatibility ======================= Not a problem for this GLEP. There is no previous standard as the issue did not exist before. This GLEP is to prevent future compatibility issues. Categories of package managers ============================== We distinguish four categories of package managers. While a package manager can transition from one category to another, it can not be in two categories at the same time. It can be in a state of transition though. *Primary Package Manager* There is one primary package manager. Currently this position is held by portage. The primary package manager is assigned by the council and all packages in the official tree must be installable by a useable version of the primary package manager. *Candidate Primary Package Managers* A candidate Primary Package Manager does aim, or show an aim, at replacing the current primary package manager. At a point where the package manager is deemed stable a decision must be made whether this package manager should become the new primary package manager. At that point the `primary package manager transition phase`_ starts. *Secondary Package Managers* A secondary package manager is a package manager that coexists with the primary package manager, while not aiming to replace it. Package managers that would fall into this category are: - Experimental package managers. Package managers whose purpose it is to try out new features. - Focussed package managers. For example a package manager that allows the use of rpm formatted binary packages would be an example. *Third Party Package Managers* A third party package manager is any package manager that lacks recognition from gentoo as being in any other category. A third party package manager may or may not have a gentoo package, but is not supported beyond that. Package manager requirements ============================ As a package manager is in a state of higher support there are higher requirements to it. The purpose of these requirements is to ensure the unity of the distribution and the package tree. For this purpose it is needed that there is only one primary package manager. primary package manager requirements ------------------------------------ The primary package manager is the package manager that sets the standards for the tree. All ebuilds in the tree must function with the primary package manager. As the primary package manager sets the standard it does not have to maintain compatibility with other package managers. The primary package manager does however have the responsibility that it must be very stable. The primary package manager must maintain compatibility with old versions of itself for extended periods of time. This compatibilty time is set by the council. The suggested time would be one year from the point that there is a compatible stable version for all supported architectures. Another compatibilty requirement for the primary package manager is a limited forward compatibility. It must always be possible to transition from the unstable version of the primary package manager to a stable version. This may be done either by first introducing reading compatibility for a new format and only having write support later. Another way would be the provision of a conversion tool that ensures that the on disk information maintained by the package manager is supported by the stable package manager. The primary package manager is maintained on official gentoo infrastructure, under control of gentoo developers. candidate primary package manager requirements ------------------------------------------------ A candidate primary package manager aims to replace the primary package manager. The council is responsible for deciding whether this is done. The requirements are there to ensure that it is actually possible to transition a candidate primary package manager into the primary package manager. First of all, there must exist a transition path. This means that the on disk data of the primary package manager can be used by (or converted to a format usable by) the candidate primary package manager. Second, there must be a test path. It must be possible for the developers to test out the candidate primary package manager on their working systems. This means that the transition path must exist. This also means that there are no serious obstacles for reverting to the current primary package manager. Third, there must exist an ebuild test path. It must be possible for package managers to test ebuilds in one tree for both the primary as well as the candidate primary package manager. It is not an issue if this requires a special mode for the candidate primary package manager. It is not an issue either if compatibilty can be achieved by unmerging the package in the candidate primary package manager. Fourth, there must be support. This means that the package manager is actively maintained under control of gentoo. If it is not maintained on gentoo infrastructure, the means must be there to move the package manager, with its change history, to gentoo infrastructure. This means that it must be maintained on a gentoo supported versioning system, or on a version system whose history can be converted to a gentoo supported versioning system. secondary package manager requirements -------------------------------------- A secondary package manager is a package manager that instead of directly aiming at replacing portage as primary package manager. As such a secondary package manager does not set the standard on the tree, but follows the standard set by the primary package manager. There are two kinds of secondary package managers. The first kind is formed by those that do not maintain their own installed package database, but work with the package database of the primary package manager. While these package managers can put additional information in the database, these entries must remain compatible with the primary package managers. Verification, reference, and deinstallation by the primary package manager must remain functional. The second kind is formed by those package managers that maintain their own package database, or a package database incompatible with the primary package manager. To ensure the secondary role of these package managers the support in the tree for these package manager is provided along with restrictions. The first restriction is that no packages in the tree must rely on the secondary package manager. While packages may provide a level of support (while being compatible with the primary package manager) this may not result in a significant increase of features. If this were allowed, this would mean that while they technically work with the primary package manager, there would be significant incentive to use the secondary package manager. As the use of this secondary package manager disallows the paralel use of the primary package manager, this would result in users using the secondary package manager as their primary package manager. Users are allowed to make their own choices. However by making the tree favor a package manager that is not the primary package manager, this will lead to the secondary package manager becomming the effective primary package manager. As this will be a decision by default instead of a concious choice by the council, this is an undesirable result. There is one exclusion for the restriction of packages that only work with or have significant improvements with the secondary package manager. That is packages that by their nature are only usable with this secondary package manager. An example would be a graphical frontend to the secondary package manager. If a secondary package manager works along the primary package manager, but by itself does not have the capabilities of becoming a primary package manager the risks of choice by default are lower. As a result, the council could choose to allow the inclusion of packages that work only or significantly better with this secondary package manager. For example at a point where there is a stable, functional, package manager that can handle RPM format packages, the council could decide to include these packages directly in the tree, instead of using wrapper scripts for those packages that are only provided in the RPM format. Such a decision does imply that the maintainers of the primary package manager must take this secondary package manager into account. third party package manager requirements ---------------------------------------- A third party package manager is just that. It is a package manager without any support within gentoo. As there is no control by gentoo over the package manager this means that there are no requirements on the package manager. This complete lack of control however also translates to the fact that gentoo can not make package manager specific changes to support this package manager. Package manager specific means that it is possible to request changes that make the tree more independent of the primary package manager. These changes must however be agnostic of the package manager, and only make it easier to have alternative package managers. transition phases ================= primary package manager transition phase ---------------------------------------- A candidate primary package manager can be chosen to become primary package manager. This can only happen by council decision. This decision can only be made when the candiate primary package manager is stable on all stable architectures. (all architectures except experimental ones). After the decision has been made to replace the primary package manager, the transition phase starts. The use of the old stable package manager must remain supported for a period of 6 months. This means that core packages must be installable by this package manager. Further the possibility to convert the system automatically to the new primary package manager must be available for at least 18 months, but preferably longer (enable installing the new package manager from the old one). During the transition phase packages are allowed in the tree that use the new features of the new primary package manager. While backward compatibility with the previous primary package manager must be maintained a forward compatibility is no longer needed. Secondary package manager to candidate primary package manager transition ------------------------------------------------------------------------- The transition from secondary package manager to candidate primary package manager is straightforward. The secondary package manager must satisfy all requirements for a candidate primary package manager. At that point its maintainers can announce that they are changing the status to candidate primary package manager. This allows a greater support from gentoo in achieving that goal. Third party to other transition ------------------------------- When a third party package manager wants to transition into one of the other categories (except primary package manager) it must satisfy all requirements for that category. References ========== .. _paludis: http://paludis.berlios.de/ .. _pkgcore: http://gentooexperimental.org/~ferringb/bzr/pkgcore/ .. _Open Publication License: http://www.opencontent.org/openpub/ Copyright ========= This document is copyright 2006 by Paul de Vrieze and licensed under the `Open Publication License`_.
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