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31 <tr class="field"><th class="field-name">GLEP:</th><td class="field-body">49</td>
32 </tr>
33 <tr class="field"><th class="field-name">Title:</th><td class="field-body">Alternative Package Manager requirements</td>
34 </tr>
35 <tr class="field"><th class="field-name">Version:</th><td class="field-body">2215</td>
36 </tr>
37 <tr class="field"><th class="field-name">Last-Modified:</th><td class="field-body"><a class="reference" href="http://www.gentoo.org/cgi-bin/viewcvs.cgi/xml/htdocs/proj/en/glep/glep-0049.txt?cvsroot=gentoo">2006-05-20 16:18:10 +0200 (Sat, 20 May 2006)</a></td>
38 </tr>
39 <tr class="field"><th class="field-name">Author:</th><td class="field-body">Paul de Vrieze &lt;pauldv&#32;&#97;t&#32;gentoo.org&gt;,</td>
40 </tr>
41 <tr class="field"><th class="field-name">Status:</th><td class="field-body">Draft</td>
42 </tr>
43 <tr class="field"><th class="field-name">Type:</th><td class="field-body">Standards Track</td>
44 </tr>
45 <tr class="field"><th class="field-name">Content-Type:</th><td class="field-body"><a class="reference" href="glep-0002.html">text/x-rst</a></td>
46 </tr>
47 <tr class="field"><th class="field-name">Created:</th><td class="field-body">18-May-2006</td>
48 </tr>
49 <tr class="field"><th class="field-name">Post-History:</th><td class="field-body">19-May-2006</td>
50 </tr>
51 </tbody>
52 </table>
53 <hr />
54 <div class="contents topic">
55 <p class="topic-title first"><a id="contents" name="contents">Contents</a></p>
56 <ul class="simple">
57 <li><a class="reference" href="#abstract" id="id7" name="id7">Abstract</a></li>
58 <li><a class="reference" href="#motivation" id="id8" name="id8">Motivation</a></li>
59 <li><a class="reference" href="#rationale" id="id9" name="id9">Rationale</a></li>
60 <li><a class="reference" href="#backwards-compatibility" id="id10" name="id10">Backwards Compatibility</a></li>
61 <li><a class="reference" href="#categories-of-package-managers" id="id11" name="id11">Categories of package managers</a></li>
62 <li><a class="reference" href="#package-manager-requirements" id="id12" name="id12">Package manager requirements</a><ul>
63 <li><a class="reference" href="#primary-package-manager-requirements" id="id13" name="id13">Primary package manager requirements</a></li>
64 <li><a class="reference" href="#candidate-primary-package-manager-requirements" id="id14" name="id14">Candidate primary package manager requirements</a></li>
65 <li><a class="reference" href="#secondary-package-manager-requirements" id="id15" name="id15">Secondary package manager requirements</a></li>
66 <li><a class="reference" href="#third-party-package-manager-requirements" id="id16" name="id16">Third party package manager requirements</a></li>
67 </ul>
68 </li>
69 <li><a class="reference" href="#transition-phases" id="id17" name="id17">Transition phases</a><ul>
70 <li><a class="reference" href="#primary-package-manager-transition-phase" id="id18" name="id18">Primary package manager transition phase</a></li>
71 <li><a class="reference" href="#secondary-package-manager-to-candidate-primary-package-manager-transition" id="id19" name="id19">Secondary package manager to candidate primary package manager transition</a></li>
72 <li><a class="reference" href="#third-party-to-other-transition" id="id20" name="id20">Third party to other transition</a></li>
73 </ul>
74 </li>
75 <li><a class="reference" href="#references" id="id21" name="id21">References</a></li>
76 <li><a class="reference" href="#copyright" id="id22" name="id22">Copyright</a></li>
77 </ul>
78 </div>
79 <div class="section">
80 <h1><a class="toc-backref" href="#id7" id="abstract" name="abstract">Abstract</a></h1>
81 <p>This GLEP describes four classes of package managers. What the requirements for
82 them are, and what support they can receive.</p>
83 </div>
84 <div class="section">
85 <h1><a class="toc-backref" href="#id8" id="motivation" name="motivation">Motivation</a></h1>
86 <p>To set a standard that package managers that seek Gentoo project approval and
87 support should adhere to.</p>
88 </div>
89 <div class="section">
90 <h1><a class="toc-backref" href="#id9" id="rationale" name="rationale">Rationale</a></h1>
91 <p>Currently Portage is showing its age. The code of Portage does not seem to be
92 salvageable for new versions. As of the date of publication, there are two known
93 alternative package managers that claim a level of Portage compatibility. These
94 alternatives are <a class="reference" href="http://paludis.berlios.de/">paludis</a> <a class="footnote-reference" href="#id1" id="id2" name="id2">[1]</a> and <a class="reference" href="http://gentooexperimental.org/~ferringb/bzr/pkgcore/">pkgcore</a> <a class="footnote-reference" href="#id3" id="id4" name="id4">[2]</a>. Before these alternatives are
95 developed further, a set of rules should be created to level the playing field
96 and ensuring that decisions can be made clearly.</p>
97 </div>
98 <div class="section">
99 <h1><a class="toc-backref" href="#id10" id="backwards-compatibility" name="backwards-compatibility">Backwards Compatibility</a></h1>
100 <p>Not a problem for this GLEP. There is no previous standard as the issue did not
101 exist before. This GLEP is to prevent future compatibility issues.</p>
102 </div>
103 <div class="section">
104 <h1><a class="toc-backref" href="#id11" id="categories-of-package-managers" name="categories-of-package-managers">Categories of package managers</a></h1>
105 <p>We distinguish four categories of package managers. While a package manager can
106 transition from one category to another, it can not be in two categories at the
107 same time. It can be in a state of transition though.</p>
108 <dl class="docutils">
109 <dt><em>Primary Package Manager</em></dt>
110 <dd>There is one primary package manager. Currently this position is held by
111 Portage. The primary package manager is assigned by the council and all
112 packages in the official tree must be installable by a usable version of the
113 primary package manager.</dd>
114 <dt><em>Candidate Primary Package Managers</em></dt>
115 <dd>A candidate Primary Package Manager does aim, or show an aim, at replacing
116 the current primary package manager. At a point where the package manager is
117 deemed stable a decision must be made whether this package manager should
118 become the new primary package manager. At that point the <a class="reference" href="#primary-package-manager-transition-phase">Primary package
119 manager transition phase</a> starts.</dd>
120 <dt><em>Secondary Package Managers</em></dt>
121 <dd><p class="first">A secondary package manager is a package manager that coexists with the
122 primary package manager, while not aiming to replace it. Examples of package
123 managers that would fall into this category are:</p>
124 <ul class="last simple">
125 <li>Experimental package managers. Package managers whose purpose it is to try
126 out new features.</li>
127 <li>Focused package managers. For example a package manager that allows the
128 use of RPM formatted binary packages would be an example.</li>
129 <li>Alternate package managers. Package managers that aim to coexist with the
130 primary package manager. They might for example offer a nicer user
131 interface than the primary package manager (e.g. show a cow instead of
132 compilation messages).</li>
133 </ul>
134 </dd>
135 <dt><em>Third Party Package Managers</em></dt>
136 <dd>A third party package manager is any package manager that lacks recognition
137 from Gentoo as being in any other category. A third party package manager may
138 or may not have a Gentoo package, but is not supported beyond that.</dd>
139 </dl>
140 </div>
141 <div class="section">
142 <h1><a class="toc-backref" href="#id12" id="package-manager-requirements" name="package-manager-requirements">Package manager requirements</a></h1>
143 <p>As a package manager is in a state of higher support there are higher
144 requirements to it. The purpose of these requirements is to ensure the unity of
145 the distribution and the package tree. For this purpose it is needed that there
146 is only one primary package manager.</p>
147 <div class="section">
148 <h2><a class="toc-backref" href="#id13" id="primary-package-manager-requirements" name="primary-package-manager-requirements">Primary package manager requirements</a></h2>
149 <p>The primary package manager is the package manager that sets the standards for
150 the tree. All ebuilds in the tree must function with the primary package
151 manager. As the primary package manager sets the standard it does not have to
152 maintain compatibility with other package managers.</p>
153 <p>The primary package manager does however have the responsibility that it must be
154 very stable. The primary package manager must maintain compatibility with old
155 versions of itself for extended periods of time. This compatibility time is set
156 by the council. The suggested time would be one year from the point that there
157 is a compatible stable version for all supported architectures.</p>
158 <p>Another compatibility requirement for the primary package manager is a limited
159 forward compatibility. It must always be possible to transition from the
160 unstable version of the primary package manager to a stable version. This may be
161 done either by first introducing reading compatibility for a new format and only
162 having write support later. Another way would be the provision of a conversion
163 tool that ensures that the on disk information maintained by the package manager
164 is supported by the stable package manager.</p>
165 <p>The primary package manager is maintained on official Gentoo infrastructure,
166 under control of Gentoo developers.</p>
167 </div>
168 <div class="section">
169 <h2><a class="toc-backref" href="#id14" id="candidate-primary-package-manager-requirements" name="candidate-primary-package-manager-requirements">Candidate primary package manager requirements</a></h2>
170 <p>A candidate primary package manager aims to replace the primary package
171 manager. The council is responsible for deciding whether this is done. The
172 requirements are there to ensure that it is actually possible to transition a
173 candidate primary package manager into the primary package manager.</p>
174 <p>First of all, there must exist a transition path. This means that the on disk
175 data of the primary package manager can be used by (or converted to a format
176 usable by) the candidate primary package manager.</p>
177 <p>Second, there must be a test path. It must be possible for the developers to
178 test out the candidate primary package manager on their working systems. This
179 means that the transition path must exist. This also means that there are no
180 serious obstacles for reverting to the current primary package manager. This
181 reverting must also be usable when it is decided that the candidate will not
182 become primary package manager, for example because serious design flaws or bugs
183 were found. Ideally, the Candidate Primary Package Manager and the Primary
184 Package Manager can be installed simultaneously. If not, clear instructions must
185 be provided for both ways of transitioning.</p>
186 <p>Third, there must exist an ebuild test path. It must be possible for package
187 managers to test ebuilds in one tree for both the primary as well as the
188 candidate primary package manager. It is not an issue if this requires a special
189 mode for the candidate primary package manager. It is not an issue either if
190 compatibility can be achieved by having the candidate primary package manager
191 unmerge the package.</p>
192 <p>Fourth, there must be support. This means that the package manager is actively
193 maintained under control of Gentoo. If it is not maintained on Gentoo
194 infrastructure, the means must be there to move the package manager, with its
195 change history, to Gentoo infrastructure. This means that it must be maintained
196 on a Gentoo supported versioning system, or on a version system whose history
197 can be converted to a Gentoo supported versioning system.</p>
198 <p>Fifth, release capabilities. There must exist automated tools that use the
199 candidate primary package manager to create release media that have similar
200 capabilities as those released using the old primary package manager. The exact
201 requirements are determined by the Release Engineering project, but should not
202 be significantly beyond what is currently implemented using the primary package
203 manager.</p>
204 </div>
205 <div class="section">
206 <h2><a class="toc-backref" href="#id15" id="secondary-package-manager-requirements" name="secondary-package-manager-requirements">Secondary package manager requirements</a></h2>
207 <p>A secondary package manager is a package manager that instead of directly aiming
208 at replacing the current primary package manager as primary package manager aims
209 to cooperate with the primary package manager. As such a secondary package
210 manager does not set the standard on the tree, but follows the standard set by
211 the primary package manager.</p>
212 <p>There are two kinds of secondary package managers. The first kind is formed by
213 those that do not maintain their own installed package database, but work with
214 the package database of the primary package manager. While these package
215 managers can put additional information in the database, these entries must
216 remain compatible with the primary package managers. Verification, reference,
217 and deinstallation by the primary package manager must remain functional.</p>
218 <p>The second kind is formed by those package managers that maintain their own
219 package database, or a package database incompatible with the primary package
220 manager. To ensure the secondary role of these package managers the support in
221 the tree for these package manager is provided along with restrictions.</p>
222 <p>The first restriction is that no packages in the tree must rely on the secondary
223 package manager. While packages may provide a level of support (while being
224 compatible with the primary package manager) this may not result in a
225 significant increase of features. If this were allowed, this would mean that
226 while they technically work with the primary package manager, there would be
227 significant incentive to use the secondary package manager. As the use of this
228 secondary package manager disallows the parallel use of the primary package
229 manager, this would result in users using the secondary package manager as their
230 primary package manager.</p>
231 <p>Users are allowed to make their own choices. However by making the tree favour a
232 package manager that is not the primary package manager, this will lead to the
233 secondary package manager becoming the effective primary package manager. As
234 this will be a decision by default instead of a conscious choice by the council,
235 this is an undesirable result.</p>
236 <p>There is one exclusion for the restriction of packages that only work with or
237 have significant improvements with the secondary package manager. That is
238 packages that by their nature are only usable with this secondary package
239 manager. An example would be a graphical front-end to the secondary package
240 manager.</p>
241 <p>If a secondary package manager works along the primary package manager, but by
242 itself does not have the capabilities of becoming a primary package manager the
243 risks of choice by default are lower. As a result, the council could choose to
244 allow the inclusion of packages that work only or significantly better with this
245 secondary package manager. For example at a point where there is a stable,
246 functional, package manager that can handle RPM format packages, the council
247 could decide to include these packages directly in the tree, instead of using
248 wrapper scripts for those packages that are only provided in the RPM
249 format. Such a decision does imply that the maintainers of the primary package
250 manager must take this secondary package manager into account.</p>
251 </div>
252 <div class="section">
253 <h2><a class="toc-backref" href="#id16" id="third-party-package-manager-requirements" name="third-party-package-manager-requirements">Third party package manager requirements</a></h2>
254 <p>A third party package manager is just that. It is a package manager without any
255 support within Gentoo. As there is no control by Gentoo over the package manager
256 this means that there are no requirements on the package manager.</p>
257 <p>This complete lack of control however also translates to the fact that Gentoo
258 can not make package manager specific changes to support this package
259 manager. Package manager specific means that it is possible to request changes
260 that make the tree more independent of the primary package manager. These
261 changes must however be agnostic of the package manager, and only make it easier
262 to have alternative package managers.</p>
263 </div>
264 </div>
265 <div class="section">
266 <h1><a class="toc-backref" href="#id17" id="transition-phases" name="transition-phases">Transition phases</a></h1>
267 <div class="section">
268 <h2><a class="toc-backref" href="#id18" id="primary-package-manager-transition-phase" name="primary-package-manager-transition-phase">Primary package manager transition phase</a></h2>
269 <p>A candidate primary package manager can be chosen to become primary package
270 manager. This can only happen by council decision. This decision can only be
271 made when the candidate primary package manager is stable on all stable
272 architectures. (all architectures except experimental ones).</p>
273 <p>After the decision has been made to replace the primary package manager, the
274 transition phase starts. The use of the old stable package manager must remain
275 supported for a period of 6 months. This means that core packages must be
276 installable by this package manager. Further the possibility to convert the
277 system automatically to the new primary package manager must be available for at
278 least 18 months, but preferably longer (enable installing the new package
279 manager from the old one).</p>
280 <p>During the transition phase packages are allowed in the tree that use the new
281 features of the new primary package manager. While backward compatibility with
282 the previous primary package manager must be maintained a forward compatibility
283 is no longer needed.</p>
284 </div>
285 <div class="section">
286 <h2><a class="toc-backref" href="#id19" id="secondary-package-manager-to-candidate-primary-package-manager-transition" name="secondary-package-manager-to-candidate-primary-package-manager-transition">Secondary package manager to candidate primary package manager transition</a></h2>
287 <p>The transition from secondary package manager to candidate primary package
288 manager is straightforward. The secondary package manager must satisfy all
289 requirements for a candidate primary package manager. At that point its
290 maintainers can announce that they are changing the status to candidate primary
291 package manager. This allows a greater support from Gentoo in achieving that
292 goal.</p>
293 </div>
294 <div class="section">
295 <h2><a class="toc-backref" href="#id20" id="third-party-to-other-transition" name="third-party-to-other-transition">Third party to other transition</a></h2>
296 <p>When a third party package manager wants to transition into one of the other
297 categories (except primary package manager) it must satisfy all requirements for
298 that category.</p>
299 </div>
300 </div>
301 <div class="section">
302 <h1><a class="toc-backref" href="#id21" id="references" name="references">References</a></h1>
303 <table class="docutils footnote" frame="void" id="id1" rules="none">
304 <colgroup><col class="label" /><col /></colgroup>
305 <tbody valign="top">
306 <tr><td class="label"><a class="fn-backref" href="#id2" name="id1">[1]</a></td><td><a class="reference" href="http://paludis.berlios.de/">http://paludis.berlios.de/</a></td></tr>
307 </tbody>
308 </table>
309 <table class="docutils footnote" frame="void" id="id3" rules="none">
310 <colgroup><col class="label" /><col /></colgroup>
311 <tbody valign="top">
312 <tr><td class="label"><a class="fn-backref" href="#id4" name="id3">[2]</a></td><td><a class="reference" href="http://gentooexperimental.org/~ferringb/bzr/pkgcore/">http://gentooexperimental.org/~ferringb/bzr/pkgcore/</a></td></tr>
313 </tbody>
314 </table>
315 <table class="docutils footnote" frame="void" id="id5" rules="none">
316 <colgroup><col class="label" /><col /></colgroup>
317 <tbody valign="top">
318 <tr><td class="label"><a class="fn-backref" href="#id6" name="id5">[3]</a></td><td><a class="reference" href="http://www.opencontent.org/openpub/">http://www.opencontent.org/openpub/</a></td></tr>
319 </tbody>
320 </table>
321 </div>
322 <div class="section">
323 <h1><a class="toc-backref" href="#id22" id="copyright" name="copyright">Copyright</a></h1>
324 <p>This document is copyright 2006 by Paul de Vrieze and licensed under the
325 <a class="reference" href="http://www.opencontent.org/openpub/">Open Publication License</a> <a class="footnote-reference" href="#id5" id="id6" name="id6">[3]</a>.</p>
326 </div>
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