Commit merging: scope and cadence
Commits are merged into branches according to criteria specific to each phase of the Ceph release lifecycle. This chapter codifies these criteria.
Development releases (i.e. x.0.z)
What ?
Features
Bug fixes
Where ?
Features are merged to the master branch. Bug fixes should be merged to the corresponding named branch (e.g. nautilus for 14.0.z, pacific for 16.0.z, etc.). However, this is not mandatory - bug fixes and documentation enhancements can be merged to the master branch as well, since the master branch is itself occasionally merged to the named branch during the development releases phase. In either case, if a bug fix is important it can also be flagged for backport to one or more previous stable releases.
When ?
After each stable release, candidate branches for previous releases enter phase 2 (see below). For example: the jewel named branch was created when the infernalis release candidates entered phase 2. From this point on, master was no longer associated with infernalis. After he named branch of the next stable release is created, master will be occasionally merged into it.
Branch merges
The latest stable release branch is merged periodically into master.
The master branch is merged periodically into the branch of the stable release.
The master is merged into the stable release branch immediately after each development (x.0.z) release.
Stable release candidates (i.e. x.1.z) phase 1
What ?
Bug fixes only
Where ?
The stable release branch (e.g. jewel for 10.0.z, luminous for 12.0.z, etc.) or master. Bug fixes should be merged to the named branch corresponding to the stable release candidate (e.g. jewel for 10.1.z) or to master. During this phase, all commits to master will be merged to the named branch, and vice versa. In other words, it makes no difference whether a commit is merged to the named branch or to master - it will make it into the next release candidate either way.
When ?
After the first stable release candidate is published, i.e. after the x.1.0 tag is set in the release branch.
Branch merges
The stable release branch is merged periodically into master.
The master branch is merged periodically into the stable release branch.
The master branch is merged into the stable release branch immediately after each x.1.z release candidate.
Stable release candidates (i.e. x.1.z) phase 2
What ?
Bug fixes only
Where ?
The stable release branch (e.g. mimic for 13.0.z, octopus for 15.0.z ,etc.). During this phase, all commits to the named branch will be merged into master. Cherry-picking to the named branch during release candidate phase 2 is performed manually since the official backporting process begins only when the release is pronounced "stable".
When ?
After Sage Weil announces that it is time for phase 2 to happen.
Branch merges
The stable release branch is occasionally merged into master.
Stable releases (i.e. x.2.z)
What ?
Bug fixes
Features are sometime accepted
Commits should be cherry-picked from master when possible
Commits that are not cherry-picked from master must pertain to a bug unique to the stable release
See also the backport HOWTO document
Where ?
The stable release branch (hammer for 0.94.x, infernalis for 9.2.x, etc.)
When ?
After the stable release is published, i.e. after the "vx.2.0" tag is set in the release branch.
Branch merges
Never