|Andrew Bogott||Jul 2, 2012 12:16 pm|
|Russell Bryant||Jul 2, 2012 12:26 pm|
|Joshua Harlow||Jul 2, 2012 2:41 pm|
|Joshua Harlow||Jul 2, 2012 2:54 pm|
|Gabriel Hurley||Jul 2, 2012 3:18 pm|
|John Postlethwait||Jul 2, 2012 4:42 pm|
|Christopher B Ferris||Jul 2, 2012 5:41 pm|
|Thierry Carrez||Jul 3, 2012 2:31 am|
|Thierry Carrez||Jul 3, 2012 2:34 am|
|Doug Hellmann||Jul 3, 2012 5:37 am|
|James E. Blair||Jul 3, 2012 6:55 am|
|Joshua Harlow||Jul 3, 2012 10:46 am|
|Dan Prince||Jul 3, 2012 10:59 am|
|Gabriel Hurley||Jul 3, 2012 11:59 am|
|Andrew Bogott||Jul 3, 2012 12:47 pm|
|Joshua Harlow||Jul 3, 2012 2:09 pm|
|James E. Blair||Jul 3, 2012 2:54 pm|
|Eric Windisch||Jul 3, 2012 3:47 pm|
|Andrew Bogott||Jul 3, 2012 3:54 pm|
|Gabriel Hurley||Jul 3, 2012 4:53 pm|
|Timothy Daly||Jul 3, 2012 5:27 pm|
|Monty Taylor||Jul 3, 2012 6:17 pm|
|Thierry Carrez||Jul 4, 2012 2:56 am|
|Gabriel Hurley||Jul 4, 2012 3:17 pm|
|Eric Windisch||Jul 4, 2012 4:11 pm|
|Christopher B Ferris||Jul 5, 2012 4:29 am|
|Sean Dague||Jul 5, 2012 6:55 am|
|Doug Hellmann||Jul 5, 2012 7:16 am|
|Joshua Harlow||Jul 5, 2012 10:21 am|
|Mark McLoughlin||Jul 18, 2012 2:01 am|
|Mark McLoughlin||Jul 18, 2012 2:13 am|
|Mark McLoughlin||Jul 18, 2012 2:16 am|
|Mark McLoughlin||Jul 18, 2012 2:23 am|
|Thierry Carrez||Jul 18, 2012 4:00 pm|
|Doug Hellmann||Jul 23, 2012 8:50 am|
|Thierry Carrez||Jul 23, 2012 8:59 am|
|Doug Hellmann||Jul 23, 2012 9:04 am|
|Eric Windisch||Aug 2, 2012 1:05 pm|
|Christopher B Ferris||Aug 2, 2012 2:08 pm|
|Vishvananda Ishaya||Aug 2, 2012 3:47 pm|
|Jay Pipes||Aug 2, 2012 5:18 pm|
|Zhongyue Luo||Aug 2, 2012 5:24 pm|
|Eric Windisch||Aug 2, 2012 5:51 pm|
|Mark McLoughlin||Aug 2, 2012 10:26 pm|
|Thierry Carrez||Aug 3, 2012 2:49 am|
|Thierry Carrez||Aug 3, 2012 4:02 am|
|Jay Pipes||Aug 3, 2012 9:25 am|
|Eric Windisch||Aug 3, 2012 9:34 am|
|Subject:||Re: [Openstack] best practices for merging common into specific projects|
|From:||Dan Prince (dpri...@redhat.com)|
|Date:||Jul 3, 2012 10:59:53 am|
----- Original Message -----
From: "Russell Bryant" <rbry...@redhat.com>
Cc: "Andrew Bogott" <abog...@wikimedia.org>, open...@lists.launchpad.net
Sent: Monday, July 2, 2012 3:26:56 PM
Subject: Re: [Openstack] best practices for merging common into specific
On 07/02/2012 03:16 PM, Andrew Bogott wrote:
The openstack-common project is subject to a standard code-review process (and, soon, will also have Jenkins testing gates.) Sadly, patches that are merged into openstack-common are essentially orphans. Bringing those changes into actual use requires yet another step, a 'merge from common' patch where the code changes in common are copied into a specific project (e.g. nova.) Merge-from-common patches are generated via an automated process. Specific projects express dependencies on specific common components via a config file, e.g. 'nova/openstack-common.conf'. The actual file copy is performed by 'openstack-common/update.py,' and its behavior is governed by the appropriate openstack-common.conf file.
When should changes from common be merged into other projects? What should a 'merge-from-common' patch look like? What code-review standards should core committers observe when reviewing merge-from-common patches?
I. As soon as a patch drops into common, the patch author should submit merge-from-common patches to all affected projects. A. (This should really be done by a bot, but that's not going to happen overnight)
All of the APIs in openstack-common right now are considered to be in incubation, meaning that breaking changes could be made. I don't think automated merges are good for anything in incubation.
Automation would be suitable for stable APIs. Once an API is no longer in incubation, we should be looking at how to make releases and treat it as a proper library. The copy/paste madness should be limited to APIs still in incubation.
There are multiple APIs close or at the point where I think we should be able to commit to them. I'll leave the specifics for a separate discussion, but I think moving on this front is key to reducing the pain we are seeing with code copying.
II. In the event that I. is not observed, merge-from-common patches will contain bits from multiple precursor patches. That is not only OK, but encouraged. A. Keeping projects in sync with common is important! B. Asking producers of merge-from-common patches to understand the full diff will discourage the generation of such merges.
I don't see this as much different as any other patches to nova (or whatever project is using common). It should be a proper patch series. If the person pulling it in doesn't understand the merge well enough to produce the patch series with proper commit messages, then they are the wrong person to be doing the merge in the first place.
I went on a bit of a rant about this on IRC yesterday. While I agree a patch
series is appropriate for many new features and bug fixes I don't think it
should be required for keeping openstack-common in sync. Especially since we
don't merge tests from openstack-common which would help verify that the person
doing the merges doesn't mess up the order of the patchset. If we were to
include the tests from openstack-common in each project this could change my
If someone wants to split openstack-common changes into patchsets that might be
Okay in small numbers. If you are merging say 5-10 changes from openstack common
into all the various openstack projects that could translate into a rather large
number of reviews (25+) for things that have been already reviewed once. For me
using patchsets to keep openstack-common in sync just causes thrashing of
Jenkins, SmokeStack, etc. for things that have already been gated. Seems like an
awful waste of review/CI time. In my opinion patchsets are the way to go with
getting things into openstack-common... but not when syncing to projects.
Hopefully this situation is short lived however and we start using a proper
library sooner rather than later.
III. Merge-from-common patches should be the product of a single unedited run of update.py.
Disagree, see above.
A. If a merge-from-common patch breaks pep8 or a test in nova, don't fix the patch; fix the code in common.
IV. Merge-from-common patches are 'presumed justified'. That means: A. Reviewers of merge-from-common patches should consider test failures and pep8 breakages, and obvious functional problems. B. Reviewers of merge-from-common patches should not consider the usefulness, design, etc. of merge-from-common patches. Such concerns need to be handled within the common review process. C. Merges from common should get reviewed early and approved readily in order to avoid project divergence
I think core reviewers of projects using openstack-common are justified in doing critical review of new code being used by their project. A core reviewer of nova for examp[le may have a very good reason why the code is not suitable for consumption in nova that openstack-common reviewers didn't think of.
I don't think blind approvals are ever a good idea.
V. Changes to openstack-common.conf are a special case. A. Patches with openstack-common.conf changes should include the relevant merge-from-common changes. B. Such patches should /not/ include any other merge-from-common changes. C. Such patches should not only include the common merges, but should also include whatever code changes make use of the new merge. D. Such patches require the same justification and scrutiny as any other standard project patch.
This all seems fine to me.
Please discuss! If we're able to reach general agreement about this process, I will document the process in the openstack-common HACKING guidelines.
-- Russell Bryant