[Development] Notes on "Managing Qt's branches" session @ QCS 2016

[Friedemann Kleint]

Hi,

the notes are at: https://wiki.qt.io/QtCS2016_Managing_Qt_Branches

* Number of existing branches (5.6LTS, 5.7.,5.8 dev) causes a number of 
problems

** Strain on COIN which also has release branches
** Merging becomes increasingly difficult
** Hard to manage for individual developers

* Branches

** Close 5.7 after 5.7.1. We then have LTS, stable, dev.
** After 5.7 is closed and sanity bot is upgraded (to handle 
cherry-picking), go into cherrypicking mode for 5.6. Developer is 
responsible for doing the cherrypicking
** Cherry-picking technicalities need to be figured out: Let sanity bot 
verify source ("cherrypicked from") the SHA1
** In the future, exact time for closing stable branches will be 
discussed for each one individually

* Submit Policy

** Target which branch?

** Long Term Support (5.6) Branch
*** Initially equal to stable, increasingly strict over time: Fix only 
severe issues, avoid regressions.

*** Bugs: For example, P2 for the first year, P1 for year 2, rest 
Security. Try to further objectify that: Jedrzei + Friedemann
*** Tests: Fix/stabilize tests itself, add tests
*** No performance improvements unless really significant 
(relevant/reduces O(n))
*** Upgrading 3rd party (including WebEngine)
*** Support new OS versions unless introducing new platforms, no rewrite 
of QPA
*** No cleanups, positively: -> dev
*** To aid customers with issues, patches for issues in LTS to be 
locally applied can be provided, but the fixes will be pushed to higher 
versions of Qt.


Regards,
Friedemann

-- 
Friedemann Kleint
The Qt Company GmbH