[dpdk-dev] [PATCH] Changes to ABI Policy introducing major ABI versions

[Ray Kinsella]

TL;DR Abbreviation:
A major ABI version that all DPDK releases during a two year period
support. ABI versioning is managed at a project-level, in place of library-level
management. ABI changes to add new features are permitted, as long as ABI
compatibility with the major ABI version is maintained.

Detail:
This patch introduces a two year major ABI version, aligned with the LTS release
and supported by all subsequent releases within that two year period, including
the subsequent LTS release.

ABI changes that preserve ABI compatibility with the major ABI version are
permitted in subsequent releases. ABI changes, follow similar approval rules as
before with the additional gate of now requiring technical board approval. The
merging and release of ABI breaking changes would now be pushed to the
declaration of the next major ABI version.

This change encourages developers to maintain ABI compatibility with the
major ABI version, by promoting a permissive culture around those changes
that preserve ABI compatibility. This approach aligns DPDK with those projects
that declare major ABI versions (e.g. version 2.x, 3.x) and support those
versions for some period, typically two years or more.

To provide an example of how this might work in practice:

 * DPDK v20 is declared as the supported ABI version for two years, aligned with
   the DPDK v19.11 (LTS) release. All library sonames are updated to reflect the
   new ABI version, e.g. librte_eal.so.20, librte_acl.so.20...
 * DPDK v20.02 .. v21.08 releases are ABI compatible with the DPDK v20 ABI. ABI
   changes are permitted from DPDK v20.02 onwards, with the condition that ABI
   compatibility with DPDK v20 is preserved.
 * DPDK v21 is declared as the new supported ABI version for two years, aligned
   with the DPDK v21.11 (LTS) release. The DPDK v20 ABI is now depreciated,
   library sonames are updated to v21 and ABI compatibility breaking changes may
   be introduced.

Ray Kinsella (1):
  doc: Changes to ABI Policy introducing major ABI versions

 doc/guides/contributing/stable.rst     |  10 +-
 doc/guides/contributing/versioning.rst | 462 ++++++++++++++++++++++-----------
 2 files changed, 314 insertions(+), 158 deletions(-)

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