[Release-testers] RFC: Release process changes

[Tom Stellard via Release-testers]

Hi,

I would like to propose a few changes to the LLVM release process.  The
current process is documented here:  https://llvm.org/docs/HowToReleaseLLVM.html

There are two parts to this proposal.  The first is a list of clarifications,
which are things we are currently doing that aren't documented. The second
is a list of changes which would actually modify how releases are currently
managed.



*** Proposed Clarifications ***



**  Release manager is allowed to commit changes to the release branch without
    code owner approval.  However, the release manager is encouraged to consult
    with code owners or patch reviewers for non-trivial changes.

It's not practical to get code owner approval every time.  Either because there
is no code owner or because the number of backports is too high (e.g. pre-rc1 / pre-rc2).
This proposed clarification matches how releases are currently managed.


** There is no official release criteria.

We have time-based releases and when the release is 'ready' has been
up to the discretion of the release manager.  Changing the release
criteria is out of the scope of this proposal, but I do think it would
be good to have a discussion about this as a community, so I'm going to
start a separate thread to discuss this.



*** Proposed Changes ***



** Create a time-based bug-fix release schedule.  After each major release, make
   a new bug-fix release every 2 weeks for 12 weeks (6 releases total).

** Eliminate release candidates for bug-fix releases.

The current unofficial bug-fix release schedule is:

X.Y.1-rc1 (6 weeks after major release)
X.Y.1-rc2 (10 weeks after major release)
X.Y.1-final (12 weeks after major release)

I think this change will improve the overall test coverage of the release branch.
I don't think the branch itself or even the release candidates get the same
level of testing as the final releases.  If we are consistently snapshotting
the release branch and putting out releases, I think this will make it easier
and thus more likely that users will test out the release branch code.

Additionally, with more frequent bug-fix release it removes the need to have
release candidate releases. Every bug-fix release (up until the last one)
would serve the same purpose as our current release candidates in that they
are intended to give users an easier way to test the code before the final
release.


** Create clear rules for what kind of backports are accepted during each
   release phase.

* Before RC1:Patches should be limited to bug fixes, important optimization
  improvements, or completion of features that were started before the branch
  was created.  As with all phases, release managers and code owners can reject
  patches that are deemed too invasive.

* Before RC2: Patches should be limited to bug fixes or backend specific
  improvements that are determined to be very safe.

* Before RC3/Final: Major Release* Patches should be limited to critical
  bugs or regressions.
 
* Bug fix releases: Patches should be limited to bug fixes or very safe
  and critical performance improvements.  Patches must maintain both API and
  ABI compatibility with the previous major release.
 
* Final bug fix release: Patches should be limited to critical bug fixes only.



What does everyone thing about these changes?


-Tom