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diff --git a/system/doc/system_principles/misc.xml b/system/doc/system_principles/misc.xml new file mode 100644 index 0000000000..dd6c2a1336 --- /dev/null +++ b/system/doc/system_principles/misc.xml @@ -0,0 +1,198 @@ +<?xml version="1.0" encoding="utf-8" ?> +<!DOCTYPE chapter SYSTEM "chapter.dtd"> + +<chapter> + <header> + <copyright> + <year>2018</year> + <holder>Ericsson AB. All Rights Reserved.</holder> + </copyright> + <legalnotice> + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + + </legalnotice> + + <title>Support, Compatibility, Deprecations, and Removal</title> + <prepared></prepared> + <responsible></responsible> + <docno></docno> + <approved></approved> + <checked></checked> + <date>2018-05-21</date> + <rev></rev> + <file>misc.xml</file> + </header> + + <section> + <marker id="supported_releases"/> + <title>Supported Releases</title> + <p> + In general, bugs are only fixed on the latest + <seealso marker="versions#releases_and_patches">release</seealso>, + and new features are introduced in the upcoming release that is + under development. However, when we, due to internal reasons, fix + bugs on older releases, these will be available and announced as well. + </p> + <p> + Due to the above, pull requests are only accepted on the + <c>maint</c> and the <c>master</c> branches in our + <url href="https://github.com/erlang/otp">git repository</url>. + The <c>maint</c> branch contains changes planned for the next + <seealso marker="versions#releases_and_patches">maintenance patch package</seealso> + on the latest OTP release and the <c>master</c> branch contain + changes planned for the upcoming OTP release. + </p> + </section> + + <section> + <marker id="compatibility"/> + <title>Compatibility</title> + <p> + We always strive to remain as compatible as possible + even in the cases where we give no compatibility guarantees. + </p> + <p> + Different parts of the system will be handled differently + regarding compatibility. The following items describe how + different parts of the system are handled. + </p> + <taglist> + <tag>Erlang Distribution</tag> + <item> + <p> + Erlang nodes can communicate across at least + two preceding and two subsequent releases. + </p> + </item> + <tag>Compiled BEAM Code, NIF Libraries and Drivers</tag> + <item> + <p> + Compiled code can be loaded on at least two + subsequent releases. + </p> + <p> + Loading on previous releases is <em>not</em> supported. + </p> + </item> + <tag>Compiled HiPE Code</tag> + <item> + <p> + Compiled HiPE code can be loaded on the exact same build + of ERTS that was used when compiling the code. It might + however work on other builds, the emulator verifies + checksums in order to determine if it can load the code + or not. Note that HiPE has some limitations. For more + information see the documentation of the + <seealso marker="hipe:HiPE_app">HiPE</seealso> application. + </p> + </item> + <tag>APIs</tag> + <item> + <p>Compatible between releases.</p> + </item> + <tag>Compiler Warnings</tag> + <item> + <p>New warnings may be issued between releases.</p> + </item> + <tag>Command Line Arguments</tag> + <item> + <p>Incompatible changes may occur between releases.</p> + </item> + <tag>OTP Build Procedures</tag> + <item><p>Incompatible changes may occur between releases.</p></item> + </taglist> + <p> + Under certain circumstances incompatible changes might be + introduced even in parts of the system that should be compatible + between releases. Things that might trigger incompatible changes + like this are: + </p> + <taglist> + <tag>Security Issues</tag> + <item> + <p> + It might be necessary to introduce incompatible changes + in order to solve a security issue. This kind of + incompatibility might occur in a patch. + </p> + </item> + <tag>Bug Fixes</tag> + <item> + <p> + We will not be bug-compatible. A bug fix might introduce + incompatible changes. This kind of incompatibility + might occur in a patch. + </p> + </item> + <tag>Severe Previous Design Issues</tag> + <item> + <p> + Some parts of OTP were designed a very long time ago and + did not necessarily take today's computing environments into + account. In some cases the consequences of those design + decisions are too severe. This may be performance wise, + scalability wise, etc. If we deem the consequences too + severe, we might introduce incompatible changes. This kind + of incompatibility will not be introduced in a patch, but + instead in the next release. + </p> + </item> + </taglist> + <p> + Peripheral, trace, and debug functionality is at greater + risk of being changed in an incompatible way than functionality + in the language itself and core libraries used during operation. + </p> + </section> + + <section> + <marker id="deprecation"/> + <title>Deprecation</title> + <p> + Functionality is deprecated when new functionality is + introduced that is preferred to be used instead of the + old functionality that is being deprecated. The deprecation + does <em>not</em> imply removal of the functionality unless + an upcoming removal is explicitly stated in the deprecation. + </p> + <p> + Deprecated functionality will be documented as deprecated, and + compiler warnings will be issued, when appropriate, as + early as possible. That is, the new preferred functionality + will appear at the same time as the deprecation is issued. + A new deprecation will at least be announced in a release + note and the documentation. + </p> + </section> + + <section> + <marker id="removal"/> + <title>Removal</title> + <p> + Legacy solutions may eventually need to be removed. In such + cases, they will be phased out on a long enough time period + to give users the time to adapt. Before removal of + functionality it will be deprecated at least during one + release with an explicit announcement about + the upcoming removal. A new deprecation will at least be + announced in a release note and the documentation. + </p> + <p> + Peripheral, trace, and debug functionality is at greater + risk of removal than functionality in the language itself + and core libraries used during operation. + </p> + </section> + +</chapter> + |