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GLEP updates.

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12     <title>GLEP 22 -- New "keyword" system to incorporate various userlands/kernels/archs</title>
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29     <col class="field-name" />
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31     <tbody valign="top">
32     <tr class="field"><th class="field-name">GLEP:</th><td class="field-body">22</td>
33     </tr>
34     <tr class="field"><th class="field-name">Title:</th><td class="field-body">New &quot;keyword&quot; system to incorporate various userlands/kernels/archs</td>
35     </tr>
36     <tr class="field"><th class="field-name">Version:</th><td class="field-body">1.1</td>
37     </tr>
38     <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-0022.txt?cvsroot=gentoo">2004/03/07 02:20:32</a></td>
39     </tr>
40     <tr class="field"><th class="field-name">Author:</th><td class="field-body">Grant Goodyear &lt;g2boojum&#32;&#97;t&#32;gentoo.org&gt;</td>
41     </tr>
42 g2boojum 1.2 <tr class="field"><th class="field-name">Status:</th><td class="field-body">Withdrawn</td>
43 g2boojum 1.1 </tr>
44     <tr class="field"><th class="field-name">Type:</th><td class="field-body">Standards Track</td>
45     </tr>
46     <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>
47     </tr>
48     <tr class="field"><th class="field-name">Created:</th><td class="field-body">6-Mar-2004</td>
49     </tr>
50     <tr class="field"><th class="field-name">Post-History:</th><td class="field-body">6-Mar-2004</td>
51     </tr>
52     </tbody>
53     </table>
54     <hr />
55     <div class="contents topic" id="contents">
56     <p class="topic-title"><a name="contents">Contents</a></p>
57     <ul class="simple">
58 g2boojum 1.2 <li><a class="reference" href="#status" id="id14" name="id14">Status</a></li>
59     <li><a class="reference" href="#credits" id="id15" name="id15">Credits</a></li>
60     <li><a class="reference" href="#abstract" id="id16" name="id16">Abstract</a></li>
61     <li><a class="reference" href="#motivation" id="id17" name="id17">Motivation</a></li>
62     <li><a class="reference" href="#specification" id="id18" name="id18">Specification</a><ul>
63     <li><a class="reference" href="#new-variables" id="id19" name="id19">New Variables</a></li>
64     <li><a class="reference" href="#reasonable-defaults" id="id20" name="id20">Reasonable Defaults</a></li>
65     <li><a class="reference" href="#profiles" id="id21" name="id21">Profiles</a></li>
66 g2boojum 1.1 </ul>
67     </li>
68 g2boojum 1.2 <li><a class="reference" href="#rationale" id="id22" name="id22">Rationale</a></li>
69     <li><a class="reference" href="#implementation" id="id23" name="id23">Implementation</a></li>
70     <li><a class="reference" href="#backwards-compatibility" id="id24" name="id24">Backwards Compatibility</a></li>
71     <li><a class="reference" href="#id1" id="id25" name="id25">References</a></li>
72     <li><a class="reference" href="#copyright" id="id26" name="id26">Copyright</a></li>
73 g2boojum 1.1 </ul>
74     </div>
75 g2boojum 1.2 <div class="section" id="status">
76     <h1><a class="toc-backref" href="#id14" name="status">Status</a></h1>
77     <p>I'm withdrawing this GLEP. It is clear from the discussions on
78     gentoo-dev that although breaking they keywords into four components
79     is probably a good idea, the four components are <em>not</em> independent.
80     Thus, the &quot;keyword explosion&quot; that this GLEP tries to prevent is
81     inevitable. The real issue, then, is how to make the keyword
82     explosion reasonably manageable, but that's a topic for another
83     GLEP.</p>
84     </div>
85 g2boojum 1.1 <div class="section" id="credits">
86 g2boojum 1.2 <h1><a class="toc-backref" href="#id15" name="credits">Credits</a></h1>
87 g2boojum 1.1 <p>This GLEP originated from the concerns that Daniel Robbins had with
88     the <em>x86obsd</em> keyword, and his desire to make the KEYWORDS variable more
89     &quot;feature-rich&quot;. Drobbins' original idea was that we should
90     allow compound
91     keywords such as gnu/x86, gnu/ppc, and macos/ppc (which would be explicit
92     versions of the more familiar x86, ppc, and macos keywords). Method noted
93     that userland/arch failed to capture the full range of possibilities (what
94     about a GNU userland on a BSD kernel+libc?), and
95     the issue has languished due to a lack of reasonable solutions.</p>
96     </div>
97     <div class="section" id="abstract">
98 g2boojum 1.2 <h1><a class="toc-backref" href="#id16" name="abstract">Abstract</a></h1>
99 g2boojum 1.1 <p>As Gentoo branches out to support non-Linux and non-GNU systems (such
100     as Hurd or the *BSDs), the potential for an &quot;explosion&quot; of possible
101     keywords becomes rather large, since each
102     new userland/kernel/arch/whatever
103     combination would require a new keyword.
104     This GLEP proposes replacing the current
105 g2boojum 1.2 KEYWORDS variable with four variables, ARCH, USERLAND, KERNEL, and LIBC,
106 g2boojum 1.1 along with sensible defaults to keep the new system manageable.</p>
107     </div>
108     <div class="section" id="motivation">
109 g2boojum 1.2 <h1><a class="toc-backref" href="#id17" name="motivation">Motivation</a></h1>
110 g2boojum 1.1 <p>Since the beginning, Gentoo Linux has been conceived as a &quot;metadistribution&quot;
111     that combines remarkable flexibility with sensible defaults and exceptional
112     maintainablilty. The goal of the <a class="reference" href="http://www.gentoo.org/proj/en/gentoo-alt/index.xml">Gentoo-Alt</a> <a class="footnote-reference" href="#id2" id="id3" name="id3">[1]</a> project has been to extend that
113     flexibility to include systems other than GNU/Linux. For example, the author
114     of this GLEP has been working to create a <a class="reference" href="http://www.gentoo.org/proj/en/gentoo-alt/bsd/index.xml">version</a> <a class="footnote-reference" href="#id8" id="id9" name="id9">[3]</a> of Gentoo that uses
115     <a class="reference" href="http://www.openbsd.com">OpenBSD</a> <a class="footnote-reference" href="#id5" id="id6" name="id6">[2]</a> as the underlying kernel, userland, and libc. <a class="reference" href="http://www.openbsd.com">OpenBSD</a> <a class="footnote-reference" href="#id5" id="id7" name="id7">[2]</a> supports
116     a variety of different architectures, so, in principle, we would need a new
117     <em>openbsd-arch</em> keyword for each supported architecture. In fact, the situation
118     is even more complicated, because the <a class="reference" href="http://www.gentoo.org/proj/en/gentoo-alt/index.xml">Gentoo-Alt</a> <a class="footnote-reference" href="#id2" id="id4" name="id4">[1]</a> project would eventually
119     like
120     to support the option of &quot;mixing-and-matching&quot; GNU/*BSD/whatever userlands
121     and libcs irrespective of the underlying kernel. (<a class="reference" href="http://www.debian.org">Debian</a> <a class="footnote-reference" href="#id10" id="id11" name="id11">[4]</a>, for example
122     has a similar BSD <a class="reference" href="http://www.debian.org/ports/netbsd/">project</a> <a class="footnote-reference" href="#id12" id="id13" name="id13">[5]</a>, except that they have replaced the
123     BSD userland with a GNU userland.) The net result is that we would need
124     keywords that specified all possible permutations of arch, userland, kernel
125     and libc. Not fun.</p>
126     </div>
127     <div class="section" id="specification">
128 g2boojum 1.2 <h1><a class="toc-backref" href="#id18" name="specification">Specification</a></h1>
129 g2boojum 1.1 <div class="section" id="new-variables">
130 g2boojum 1.2 <h2><a class="toc-backref" href="#id19" name="new-variables">New Variables</a></h2>
131 g2boojum 1.1 <p>I suggest that we replace the single KEYWORDS variable in ebuilds
132     with four separate variables: ARCH, USERLAND, LIBC, and KERNEL.</p>
133     <blockquote>
134     <dl>
135     <dt>ARCH: </dt>
136     <dd>x86, amd64, cobalt, mips64, arm, hppa, ia64, ppc64, sparc</dd>
137     <dt>USERLAND: </dt>
138     <dd>gnu, bsd</dd>
139     <dt>LIBC: </dt>
140     <dd>glibc, openbsd, freebsd, netbsd, macosx</dd>
141     <dt>KERNEL: </dt>
142     <dd>linux, selinux, openbsd, freebsd, netbsd, macosx</dd>
143     </dl>
144     </blockquote>
145     <p>(The above examples are not meant to be complete. Hurd, for example
146     is not included because I know very little about Hurd.)
147     For each variable the standard &quot;-,-*,~&quot; prefixes would be allowed.
148     Similarly, <cite>/etc/make.conf</cite> would have ACCEPT_ARCH, ACCEPT_USERLAND,
149     ACCEPT_LIBC, and ACCEPT_KERNEL variables.</p>
150     </div>
151     <div class="section" id="reasonable-defaults">
152 g2boojum 1.2 <h2><a class="toc-backref" href="#id20" name="reasonable-defaults">Reasonable Defaults</a></h2>
153 g2boojum 1.1 <p>To keep this system manageable, we need sensible defaults. An ebuild
154     that has missing USERLAND, KERNEL, or LIBC variables is provided
155     with implicit USERLAND=&quot;gnu&quot;, KERNEL=&quot;linux&quot;, and/or LIBC=&quot;glibc&quot;
156     variables. However, once a variable is explicitly added (such as
157     KERNEL=&quot;openbsd&quot;), the default is no longer assumed. That is,
158     one would need KERNEL=&quot;openbsd linux&quot; if the ebuild is stable on
159     both openbsd and linux kernels.</p>
160     <p>The ARCH variable, on the other hand, does <em>not</em> have a default, per se.
161     Instead, if no ARCH variable exists then portage would automatically
162     add the ebuild's KEYWORD entries to ARCH. Thus, all current ebuilds
163     would still work without changes, allowing for a gradual transition
164     to the new system as the new variables are needed.</p>
165     </div>
166     <div class="section" id="profiles">
167 g2boojum 1.2 <h2><a class="toc-backref" href="#id21" name="profiles">Profiles</a></h2>
168 g2boojum 1.1 <p>Along with an explosion of keywords comes a concomitant explosion
169     of potential profiles. The good news is that profiles show up only
170     in a single directory, so an explosion there is easier to contain.
171     I suggest an arch-kernel-userland-libc-version naming scheme, with
172     the kernel-userland-libc terms defaulting to linux-gnu-glibc if
173     absent. (Yes, Chemists do tend to be fond of systematic naming
174     systems.)</p>
175     <p>One drawback to having a large number of profiles is that maintainance
176     becomes a significant problem. In fact, one could reasonably argue
177     that the current number of profiles is already too many to be
178     easily maintained. One proposal that has been raised to simplify
179     matters is the idea of stackable, or cascading, profiles, so that
180     only differences between profiles would have to be maintained.</p>
181     </div>
182     </div>
183     <div class="section" id="rationale">
184 g2boojum 1.2 <h1><a class="toc-backref" href="#id22" name="rationale">Rationale</a></h1>
185 g2boojum 1.1 <p>The proposed new &quot;keywording&quot; system is far from elegant, which is
186     a substantial drawback. On the other hand, it is simple, it requires
187     relatively minor changes (albeit ones that eventually would impact
188     every ebuild in the portage tree), and the changes can be implemented
189     gradually over time.</p>
190     </div>
191     <div class="section" id="implementation">
192 g2boojum 1.2 <h1><a class="toc-backref" href="#id23" name="implementation">Implementation</a></h1>
193 g2boojum 1.1 <p>Implementation of this GLEP would divide into adding
194     Portage functionality to support the new system and
195     modifying ebuilds to
196     comply with the new system.
197     The Portage support involves hacking Portage
198     to assemble and check a four-state
199     arch-userland-kernel-libc variable instead of the simpler
200     KEYWORD variable. One might quibble over algorithmic issues, but
201     the actual concept is pretty straightforward. Rewriting ebuilds,
202     on the other hand, is a massive undertaking. Fortunately, it is
203     also a process that can be done over whatever length of time is
204     required, since &quot;legacy&quot; ebuilds should work with no changes.</p>
205     </div>
206     <div class="section" id="backwards-compatibility">
207 g2boojum 1.2 <h1><a class="toc-backref" href="#id24" name="backwards-compatibility">Backwards Compatibility</a></h1>
208 g2boojum 1.1 <p>Backwards compatibility has already been addressed in some detail,
209     with the stated goal being a system that would leave all current
210     ebuilds in a still-functioning state after the portage modifications
211     have been made. However, we are already using an ARCH variable for
212     some arcane purpose in Portage, and that issue would still need to
213     be resolved.</p>
214     </div>
215     <div class="section" id="id1">
216 g2boojum 1.2 <h1><a class="toc-backref" href="#id25" name="id1">References</a></h1>
217 g2boojum 1.1 <table class="footnote" frame="void" id="id2" rules="none">
218     <colgroup><col class="label" /><col /></colgroup>
219     <tbody valign="top">
220     <tr><td class="label"><a name="id2">[1]</a></td><td><em>(<a class="fn-backref" href="#id3">1</a>, <a class="fn-backref" href="#id4">2</a>)</em> <a class="reference" href="http://www.gentoo.org/proj/en/gentoo-alt/index.xml">http://www.gentoo.org/proj/en/gentoo-alt/index.xml</a></td></tr>
221     </tbody>
222     </table>
223     <table class="footnote" frame="void" id="id5" rules="none">
224     <colgroup><col class="label" /><col /></colgroup>
225     <tbody valign="top">
226     <tr><td class="label"><a name="id5">[2]</a></td><td><em>(<a class="fn-backref" href="#id6">1</a>, <a class="fn-backref" href="#id7">2</a>)</em> <a class="reference" href="http://www.openbsd.com">http://www.openbsd.com</a></td></tr>
227     </tbody>
228     </table>
229     <table class="footnote" frame="void" id="id8" rules="none">
230     <colgroup><col class="label" /><col /></colgroup>
231     <tbody valign="top">
232     <tr><td class="label"><a class="fn-backref" href="#id9" name="id8">[3]</a></td><td><a class="reference" href="http://www.gentoo.org/proj/en/gentoo-alt/bsd/index.xml">http://www.gentoo.org/proj/en/gentoo-alt/bsd/index.xml</a></td></tr>
233     </tbody>
234     </table>
235     <table class="footnote" frame="void" id="id10" rules="none">
236     <colgroup><col class="label" /><col /></colgroup>
237     <tbody valign="top">
238     <tr><td class="label"><a class="fn-backref" href="#id11" name="id10">[4]</a></td><td><a class="reference" href="http://www.debian.org">http://www.debian.org</a></td></tr>
239     </tbody>
240     </table>
241     <table class="footnote" frame="void" id="id12" rules="none">
242     <colgroup><col class="label" /><col /></colgroup>
243     <tbody valign="top">
244     <tr><td class="label"><a class="fn-backref" href="#id13" name="id12">[5]</a></td><td><a class="reference" href="http://www.debian.org/ports/netbsd/">http://www.debian.org/ports/netbsd/</a></td></tr>
245     </tbody>
246     </table>
247     </div>
248     <div class="section" id="copyright">
249 g2boojum 1.2 <h1><a class="toc-backref" href="#id26" name="copyright">Copyright</a></h1>
250 g2boojum 1.1 <p>This document is licensed under the Creative Commons - Attribution / Share
251     Alike license. (<a class="reference" href="http://creativecommons.org/licenses/by-sa/1.0">http://creativecommons.org/licenses/by-sa/1.0</a>)</p>
252     </div>
253     </div>
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