doc: add section describing new abi versions
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Added a section describing new abi versions, this provides pointers to
the relevant amended rules that apply during the abi breakage window.
Also remove the large note a the head of the abi policy describing the
abi stability process that has taken place over the previous year.
Signed-off-by: Ray Kinsella <mdr@ashroe.eu>
---
V2: Updated to add removing aliases to experimental.
---
doc/guides/contributing/abi_policy.rst | 40 ++++++++++++++++++++++++------
doc/guides/contributing/abi_versioning.rst | 6 ++---
2 files changed, 35 insertions(+), 11 deletions(-)
--
2.7.4
@@ -14,8 +14,8 @@ General Guidelines
------------------
#. Major ABI versions are declared no more frequently than yearly. Compatibility
- with the major ABI version is mandatory in subsequent releases until a new
- major ABI version is declared.
+ with the major ABI version is mandatory in subsequent releases until a
+ :ref:`new major ABI version <new_abi_version>` is declared.
#. Major ABI versions are usually but not always declared aligned with a
:ref:`LTS release <stable_lts_releases>`.
#. The ABI version is managed at a project level in DPDK, and is reflected in
@@ -35,12 +35,6 @@ General Guidelines
.. note::
- In 2019, the DPDK community stated its intention to move to ABI stable
- releases, over a number of release cycles. This change begins with
- maintaining ABI stability through one year of DPDK releases starting from
- DPDK 19.11. This policy will be reviewed in 2020, with intention of
- lengthening the stability period. Additional implementation detail can be
- found in the :ref:`release notes <20_02_abi_changes>`.
Please note that this policy does not currently apply to the
:doc:`Windows build <../windows_gsg/intro>`.
@@ -288,11 +282,41 @@ added to the Release Notes:
these changes. Binaries using this library built prior to ABI version 21 will
require updating and recompilation.
+
+.. _new_abi_version:
+
+New ABI versions
+------------------
+
+A new ABI version may be declared aligned with a given release. The requirement
+to preserve compatibility with the previous major ABI version is then dropped
+for the duration of this release cycle. This is commonly known as the *ABI
+breakage window*, and some amended rules apply during this cycle:
+
+ * The requirement to preserve compatibility with the previous major ABI
+ version, as described in the section :ref:`abi_changes` does not apply.
+ * Contributors of compatibility preserving code in previous releases, are now
+ required to remove this compatibility code, as described in the section
+ :ref:`abi_changes`.
+ * Symbol versioning references to the old ABI version are updated to reference
+ the new ABI version, as described in the section.
+ :ref:`deprecating_entire_abi`.
+ * Contributors of aliases to experimental in previous releases, as described in
+ section :ref:`aliasing_experimental_symbols`, are now required to remove
+ these aliases.
+ * Finally, the *ABI breakage window* is *not* permission to circumvent the
+ other aspects of the procedures to make ABI changes described in
+ :ref:`abi_changes`, that is, 3 ACKs of the requirement to break the ABI and
+ the observance of a deprecation notice are still considered mandatory.
+
.. _experimental_apis:
Experimental
------------
+Major ABI versions are usually but not always declared aligned with a
+:ref:`LTS release <stable_lts_releases>`.
+
APIs
~~~~
@@ -673,9 +673,9 @@ symbols.
-BIND_DEFAULT_SYMBOL(rte_acl_create, _v20, 20);
+BIND_DEFAULT_SYMBOL(rte_acl_create, _v21, 21);
-Lastly, any VERSION_SYMBOL macros that point to the old version node should be
-removed, taking care to keep, where need old code in place to support newer
-versions of the symbol.
+Lastly, any VERSION_SYMBOL macros that point to the old version nodes should be
+removed, taking care to preserve any code that is shared with the new version
+node.
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