> > I would argue that we must *at least* do the following for now.
If we get this right, the extra staging branches can certainly wait to be assessed until later. IMO, any patch should have a branch in CI for each affected mainline branch, and should have the commit completely wired up (CHANGES.txt, commit message, the works), so that it can be merged straight in. If it conflicts significantly, it can be bumped back to the author/reviewer to refresh. On Thu, May 7, 2015 at 4:16 PM, Aleksey Yeschenko <alek...@apache.org> wrote: > I would argue that we must *at least* do the following for now. > > If your patch is 2.1-based, you need to create a private git branch for > that and a merged trunk branch (XXXX and XXXX-trunk). And you don’t push > anything until cassci validates all of those three branches, first. > > An issue without a link to cassci for both of those branches passing > doesn’t qualify as done to me. > > That alone will be enough to catch most merge-related regressions. > > Going with staging branches would also prevent any issues from concurrent > pushes, but given the opposition, I’m fine with dropping that requirement, > for now. > > -- > AY > > On May 7, 2015 at 18:04:20, Josh McKenzie (josh.mcken...@datastax.com) > wrote: > > > > > Merging is *hard*. Especially 2.1 -> 3.0, with many breaking API changes > > (this is before 8099, which is going to make a *world* of hurt, and will > > stick around for a year). It is *very* easy to break things, with even > the > > utmost care. > > > While I agree re:merging, I'm not convinced the proportion of commits that > will benefit from a staging branch testing pipeline is high enough to > justify the time and complexity overhead to (what I expect are) the vast > majority of commits that are smaller, incremental changes that won't > benefit from this. > > On Thu, May 7, 2015 at 9:56 AM, Ariel Weisberg < > ariel.weisb...@datastax.com> > wrote: > > > Hi, > > > > Sorry didn't mean to blame or come off snarky. I just it is important not > > to #include our release process from somewhere else. We don't have to do > > anything unless it is necessary to meet some requirement of what we are > > trying to do. > > > > So the phrase "Trunk is always releasable" definitely has some wiggle > room > > because you have to define what your release process is. > > > > If your requirement is that at any time you be able to tag trunk and ship > > it within minutes then yes staging branches help solve that problem. > > > > The reality is that the release process always takes low single digit > days > > because you branch trunk, then wait for longer running automated tests to > > run against that branch. If there happens to be a failure you may have to > > update the branch, but you have bounded how much brokeness sits between > you > > and release already. We also don't have a requirement to be able to ship > > nigh immediately. > > > > We can balance the cost of extra steps and process against the cost of > > having to delay some releases some of the time by a few days and pick > > whichever is more important. We are stilly reducing the amount of time it > > takes to get a working release. Reduced enough that we should be able to > > ship every month without difficulty. I have been on a team roughly our > size > > that shipped every three weeks without having staging branches. Trunk > broke > > infrequently enough it wasn't an issue and when it did break it wasn't > hard > > to address. The real pain point was flapping tests and the diffusion of > > responsibility that prevented them from getting fixed. > > > > If I were trying to sell staging branches I would work the angle that I > > want to be able to bisect trunk without coming across broken revisions. > > Then balance the value of that with the cost of the process. > > > > Ariel > > > > On Thu, May 7, 2015 at 10:41 AM, Benedict Elliott Smith < > > belliottsm...@datastax.com> wrote: > > > > > It's a bit unfair to characterize Aleksey as subscribing to a cargo > cult. > > > *We* agreed to define the new release process as "keeping trunk always > > > releasable". > > > > > > Your own words that catalyzed this: "If we release off trunk it is > pretty > > > much necessary for trunk to be in a releasable state all the time" > > > > > > It is possible we have been imprecise in our discussions, and people > have > > > agreed to different things. But it does seem to me we agreed to the > > > position Aleksey is taking, and he is not blindly following some other > > > process that is not ours. > > > > > > On Thu, May 7, 2015 at 3:25 PM, Ariel Weisberg < > > > ariel.weisb...@datastax.com> > > > wrote: > > > > > > > Hi, > > > > > > > > Whoah. Our process is our own. We don't have to subscribe to any > cargo > > > cult > > > > book buying seminar giving process. > > > > > > > > And whatever we do we can iterate and change until it works for us > and > > > > solves the problems we want solved. > > > > > > > > Ariel > > > > > > > > On Thu, May 7, 2015 at 10:13 AM, Aleksey Yeschenko < > alek...@apache.org > > > > > > > wrote: > > > > > > > > > Strictly speaking, the train schedule does demand that trunk, and > all > > > > > other branches, must be releasable at all times, whether you like > it > > or > > > > not > > > > > (for the record - I *don’t* like it, but here we are). > > > > > > > > > > This, and other annoying things, is what be subscribed to tick-tock > > vs. > > > > > supported branches experiment. > > > > > > > > > > > We still need to run CI before we release. So what does this buy > > us? > > > > > > > > > > Ideally (eventually?) we won’t have to run CI, including duration > > > tests, > > > > > before we release, because we’ll never merge anything that hadn’t > > > passed > > > > > the full suit, including duration tests. > > > > > > > > > > That said, perhaps it’s too much change at once. We still have > > missing > > > > > pieces of infrastructure, and TE is busy with what’s already > > > back-logged. > > > > > So let’s revisit this proposal in a few months, closer to 3.1 or > 3.2, > > > > maybe? > > > > > > > > > > -- > > > > > AY > > > > > > > > > > On May 7, 2015 at 16:56:07, Ariel Weisberg ( > > > ariel.weisb...@datastax.com) > > > > > wrote: > > > > > > > > > > Hi, > > > > > > > > > > I don't think this is necessary. If you merge with trunk, test, and > > > > someone > > > > > gets in a head of you just merge up and push to trunk anyways. Most > > of > > > > the > > > > > time the changes the other person made will be unrelated and they > > will > > > > > compose fine. If you actually conflict then yeah you test again but > > > this > > > > > doesn't happen often. > > > > > > > > > > The goal isn't to have trunk passing every single time it's to have > > it > > > > pass > > > > > almost all the time so the test history means something and when it > > > fails > > > > > it fails because it's broken by the latest merge. > > > > > > > > > > At this size I don't see the need for a staging branch to prevent > > trunk > > > > > from ever breaking. There is a size where it would be helpful I > just > > > > don't > > > > > think we are there yet. > > > > > > > > > > Ariel > > > > > > > > > > On Thu, May 7, 2015 at 5:05 AM, Benedict Elliott Smith < > > > > > belliottsm...@datastax.com> wrote: > > > > > > > > > > > A good practice as a committer applying a patch is to build and > run > > > the > > > > > > unit tests before updating the main repository, but to do this > for > > > > every > > > > > > branch is infeasible and impacts local productivity. > Alternatively, > > > > > > uploading the result to your development tree and waiting a few > > hours > > > > for > > > > > > CI to validate it is likely to result in a painful cycle of > > > > race-to-merge > > > > > > conflicts, rebasing and waiting again for the tests to run. > > > > > > > > > > > > So I would like to propose a new strategy: staging branches. > > > > > > > > > > > > Every major branch would have a parallel branch: > > > > > > > > > > > > cassandra-2.0 <- cassandra-2.0_staging > > > > > > cassandra-2.1 <- cassandra-2.1_staging > > > > > > trunk <- trunk_staging > > > > > > > > > > > > On commit, the idea would be to perform the normal merge process > on > > > the > > > > > > _staging branches only. CI would then run on every single git > ref, > > > and > > > > as > > > > > > these passed we would fast forward the main branch to the latest > > > > > validated > > > > > > staging git ref. If one of them breaks, we go and edit the > _staging > > > > > branch > > > > > > in place to correct the problem, and let CI run again. > > > > > > > > > > > > So, a commit would look something like: > > > > > > > > > > > > patch -> cassandra-2.0_staging -> cassandra-2.1_staging -> > > > > trunk_staging > > > > > > > > > > > > wait for CI, see 2.0, 2.1 are fine but trunk is failing, so > > > > > > > > > > > > git rebase -i trunk_staging <ref~1> > > > > > > fix the problem > > > > > > git rebase --continue > > > > > > > > > > > > wait for CI; all clear > > > > > > > > > > > > git checkout cassandra-2.0; git merge cassandra-2.0_staging > > > > > > git checkout cassandra-2.1; git merge cassandra-2.1_staging > > > > > > git checkout trunk; git merge trunk_staging > > > > > > > > > > > > This does introduce some extra steps to the merge process, and we > > > will > > > > > have > > > > > > branches we edit the history of, but the amount of edited history > > > will > > > > be > > > > > > limited, and this will remain isolated from the main branches. > I'm > > > not > > > > > sure > > > > > > how averse to this people are. An alternative policy might be to > > > > enforce > > > > > > that we merge locally and push to our development branches then > > await > > > > CI > > > > > > approval before merging. We might only require this to be > repeated > > if > > > > > there > > > > > > was a new merge conflict on final commit that could not > > automatically > > > > be > > > > > > resolved (although auto-merge can break stuff too). > > > > > > > > > > > > Thoughts? It seems if we want an "always releasable" set of > > branches, > > > > we > > > > > > need something along these lines. I certainly break tests by > > mistake, > > > > or > > > > > > the build itself, with alarming regularity. Fixing with merges > > > leaves a > > > > > > confusing git history, and leaves the build broken for everyone > > else > > > in > > > > > the > > > > > > meantime, so patches applied after, and development branches > based > > on > > > > > top, > > > > > > aren't sure if they broke anything themselves. > > > > > > > > > > > > > > > > > > > > > > > > -- > Joshua McKenzie > DataStax -- The Apache Cassandra Company >
