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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">2218</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 20:39:14 +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>
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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. This is from gentoo's perspective. From a
147 user perspective it is perfectly possible to use another package
148 manager. Candidate primary package managers and secondary package managers are
149 also supported in regards to bugs etc.</p>
150 <div class="section">
151 <h2><a class="toc-backref" href="#id13" id="primary-package-manager-requirements" name="primary-package-manager-requirements">Primary package manager requirements</a></h2>
152 <p>The primary package manager is the package manager that sets the standards for
153 the tree. All ebuilds in the tree must function with the primary package
154 manager. As the primary package manager sets the standard it does not have to
155 maintain compatibility with other package managers. This does not mean that the
156 actual implementation is the standard, but that the maintainers have the ability
157 to define new standards, together with the other involved gentoo projects.</p>
158 <p>The primary package manager does however have the responsibility that it must be
159 very stable. The primary package manager must maintain compatibility with old
160 versions of itself for extended periods of time. This compatibility time is set
161 by the council. The suggested time would be one year from the point that there
162 is a compatible stable version for all supported architectures.</p>
163 <p>Another compatibility requirement for the primary package manager is a limited
164 forward compatibility. It must always be possible to transition from the
165 unstable version of the primary package manager to a stable version. This may be
166 done either by first introducing reading compatibility for a new format and only
167 having write support later. Another way would be the provision of a conversion
168 tool that ensures that the on disk information maintained by the package manager
169 is supported by the stable package manager.</p>
170 <p>The primary package manager maintainers further have the responsibility to allow
171 competition. This means that reasonable patches from the maintainers of
172 secondary or candidate primary package managers must be applied, given that
173 these patches are as independent of that package manager as possible.</p>
174 <p>The primary package manager is maintained on official Gentoo infrastructure,
175 under control of Gentoo developers.</p>
176 </div>
177 <div class="section">
178 <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>
179 <p>A candidate primary package manager aims to replace the primary package
180 manager. The council is responsible for deciding whether this is done. The
181 requirements are there to ensure that it is actually possible to transition a
182 candidate primary package manager into the primary package manager.</p>
183 <p>First of all, there must exist a transition path. This means that the on disk
184 data of the primary package manager can be used by (or converted to a format
185 usable by) the candidate primary package manager.</p>
186 <p>Second, there must be a test path. It must be possible for the developers to
187 test out the candidate primary package manager on their working systems. This
188 means that the transition path must exist. This also means that there are no
189 serious obstacles for reverting to the current primary package manager. This
190 reverting must also be usable when it is decided that the candidate will not
191 become primary package manager, for example because serious design flaws or bugs
192 were found. Ideally, the Candidate Primary Package Manager and the Primary
193 Package Manager can be installed simultaneously. If not, clear instructions must
194 be provided for both ways of transitioning.</p>
195 <p>Third, there must exist an ebuild test path. It must be possible for package
196 managers to test ebuilds in one tree for both the primary as well as the
197 candidate primary package manager. It is not an issue if this requires a special
198 mode for the candidate primary package manager. It is not an issue either if
199 compatibility can be achieved by having the candidate primary package manager
200 unmerge the package.</p>
201 <p>Fourth, there must be support. This means that the package manager is actively
202 maintained under control of Gentoo. If it is not maintained on Gentoo
203 infrastructure, the means must be there to move the package manager, with its
204 change history, to Gentoo infrastructure. This means that it must be maintained
205 on a Gentoo supported versioning system, or on a version system whose history
206 can be converted to a Gentoo supported versioning system.</p>
207 <p>Fifth, release capabilities. There must exist automated tools that use the
208 candidate primary package manager to create release media that have similar
209 capabilities as those released using the old primary package manager. The exact
210 requirements are determined by the Release Engineering project, but should not
211 be significantly beyond what is currently implemented using the primary package
212 manager.</p>
213 </div>
214 <div class="section">
215 <h2><a class="toc-backref" href="#id15" id="secondary-package-manager-requirements" name="secondary-package-manager-requirements">Secondary package manager requirements</a></h2>
216 <p>A secondary package manager is a package manager that instead of directly aiming
217 at replacing the current primary package manager as primary package manager aims
218 to cooperate with the primary package manager. As such a secondary package
219 manager does not set the standard on the tree, but follows the standard set by
220 the primary package manager.</p>
221 <p>There are two kinds of secondary package managers. The first kind is formed by
222 those that do not maintain their own installed package database, but work with
223 the package database of the primary package manager. While these package
224 managers can put additional information in the database, these entries must
225 remain compatible with the primary package managers. Verification, reference,
226 and deinstallation by the primary package manager must remain functional.</p>
227 <p>The second kind is formed by those package managers that maintain their own
228 package database, or a package database incompatible with the primary package
229 manager. To ensure the secondary role of these package managers the support in
230 the tree for these package managers is provided along with restrictions.</p>
231 <p>The first restriction is that no packages in the tree must rely on the secondary
232 package manager. While packages may provide a level of support (while being
233 compatible with the primary package manager) this may not result in a
234 significant increase of features. If this were allowed, this would mean that
235 while they technically work with the primary package manager, there would be
236 significant incentive to use the secondary package manager. As the use of this
237 secondary package manager disallows the parallel use of the primary package
238 manager, this would result in users using the secondary package manager as their
239 primary package manager.</p>
240 <p>Users are allowed to make their own choices. However by making the tree favour a
241 package manager that is not the primary package manager, this will lead to the
242 secondary package manager becoming the effective primary package manager. As
243 this will be a decision by default instead of a conscious choice by the council,
244 this is an undesirable result.</p>
245 <p>There is one exclusion for the restriction of packages that only work with or
246 have significant improvements with the secondary package manager. That is
247 packages that by their nature are only usable with this secondary package
248 manager. An example would be a graphical front-end to the secondary package
249 manager.</p>
250 <p>If a secondary package manager works along the primary package manager, but by
251 itself does not have the capabilities of becoming a primary package manager the
252 risks of choice by default are lower. As a result, the council could choose to
253 allow the inclusion of packages that work only or significantly better with this
254 secondary package manager. For example at a point where there is a stable,
255 functional, package manager that can handle RPM format packages, the council
256 could decide to include these packages directly in the tree, instead of using
257 wrapper scripts for those packages that are only provided in the RPM
258 format. Such a decision does imply that the maintainers of the primary package
259 manager must take this secondary package manager into account.</p>
260 </div>
261 <div class="section">
262 <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>
263 <p>A third party package manager is just that. It is a package manager without any
264 support within Gentoo. As there is no control by Gentoo over the package manager
265 this means that there are no requirements on the package manager.</p>
266 <p>This complete lack of control however also translates to the fact that Gentoo
267 can not make package manager specific changes to support this package
268 manager. Package manager specific means that it is possible to request changes
269 that make the tree more independent of the primary package manager. These
270 changes must however be agnostic of the package manager, and only make it easier
271 to have alternative package managers.</p>
272 </div>
273 </div>
274 <div class="section">
275 <h1><a class="toc-backref" href="#id17" id="transition-phases" name="transition-phases">Transition phases</a></h1>
276 <div class="section">
277 <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>
278 <p>A candidate primary package manager can be chosen to become primary package
279 manager. This can only happen by council decision. This decision can only be
280 made when the candidate primary package manager is stable on all stable
281 architectures. (all architectures except experimental ones). There is a
282 incubation period of at least 3 months before a candidate primary package
283 manager can become the primary package manager.</p>
284 <p>After the decision has been made to replace the primary package manager, the
285 transition phase starts. The use of the old stable package manager must remain
286 supported for a period of 6 months. This means that core packages must be
287 installable by this package manager. Further the possibility to convert the
288 system automatically to the new primary package manager must be available for at
289 least 18 months, but preferably longer (enable installing the new package
290 manager from the old one).</p>
291 <p>During the transition phase packages are allowed in the tree that use the new
292 features of the new primary package manager. While backward compatibility with
293 the previous primary package manager must be maintained a forward compatibility
294 is no longer needed.</p>
295 </div>
296 <div class="section">
297 <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>
298 <p>The transition from secondary package manager to candidate primary package
299 manager is straightforward. The secondary package manager must satisfy all
300 requirements for a candidate primary package manager. At that point its
301 maintainers can announce that they are changing the status to candidate primary
302 package manager. This allows a greater support from Gentoo in achieving that
303 goal.</p>
304 </div>
305 <div class="section">
306 <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>
307 <p>When a third party package manager wants to transition into one of the other
308 categories (except primary package manager) it must satisfy all requirements for
309 that category.</p>
310 </div>
311 </div>
312 <div class="section">
313 <h1><a class="toc-backref" href="#id21" id="references" name="references">References</a></h1>
314 <table class="docutils footnote" frame="void" id="id1" rules="none">
315 <colgroup><col class="label" /><col /></colgroup>
316 <tbody valign="top">
317 <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>
318 </tbody>
319 </table>
320 <table class="docutils footnote" frame="void" id="id3" rules="none">
321 <colgroup><col class="label" /><col /></colgroup>
322 <tbody valign="top">
323 <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>
324 </tbody>
325 </table>
326 <table class="docutils footnote" frame="void" id="id5" rules="none">
327 <colgroup><col class="label" /><col /></colgroup>
328 <tbody valign="top">
329 <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>
330 </tbody>
331 </table>
332 </div>
333 <div class="section">
334 <h1><a class="toc-backref" href="#id22" id="copyright" name="copyright">Copyright</a></h1>
335 <p>This document is copyright 2006 by Paul de Vrieze and licensed under the
336 <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>
337 </div>
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