Re: [DISCUSS] Increased use of feature branches
> On 13 Jun 2016, at 22:49, Colin McCabe wrote: > > Feature branch code will receive fewer test runs > since it's not tested in every precommit build like trunk code is. I do > agree that good and well-thought out tests should be a precondition of > merging any big feature branch. That's fixable in Jenkins and Yetus > But we have to expect that merges will > be destabilizing in Hadoop, just like in every other software project > out there. true. The cost of a merge is generally a function of patches and duration of branch (which is really the O(#of other patches merged in to trunk) - To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org
Re: [DISCUSS] Increased use of feature branches
> > I agree with the concerns you raise around feature rot. For a feature like >> EC, it'd be untenable to leave it in trunk-incompat since the rebases would >> be impossible. I imagine we'd also need a very motivated maintainer (or >> maintainers) to handle the periodic integration of new trunk commits, since >> you'd potentially be doing it for multiple large features. If some brave >> and experienced committer is willing to own maintenance of the >> trunk-incompat branch, I think it could work. However, this is a big shift >> from how we've historically done development. >> > > If an incompatible feature is ready (like EC here), should we consider > working towards the next major release? In other words, is it okay to defer > cutting branch-3 until we have a large incompatible feature that would be a > pain to keep up with? > So the idea is that we do trunk-incompat, then when the first large incompat feature hits, we switch to branch-3? I guess this might work, though it still requires someone to maintain trunk-incompat. I think it'd also be hard to make this decision, since EC for instance at one point was targeted for 2.x.
Re: [DISCUSS] Increased use of feature branches
Thanks for clarifying Andrew. Inline. On Mon, Jun 13, 2016 at 3:59 PM, Andrew Wang wrote: > > On Fri, Jun 10, 2016 at 9:39 PM, Karthik Kambatla > wrote: > >> I would like to understand the trunk-incompat part of the proposal a >> little better. >> >> Is trunk-incompat always going to be a superset of trunk? If yes, is it >> just a change in naming convention with a hope that our approach to trunk >> stability changes as Sangjin mentioned? >> >> Or, is it okay for trunk-incompat to be based off of an older commit in >> trunk with (in)frequent rebases? This has the risk of incompatible changes >> truly rotting. Periodic rebases will ensure these changes don't rot while >> also easing the burden of hosting two branches; if we choose this route, >> some guidance of the period and who rebases will be nice. >> > > Based on my understanding from Vinod on the previous "Looking to..." > thread, it would be the latter. The goal of trunk-incompat was to avoid > adding yet-another-branch we need to commit to every time, compared to the > branch-3 proposal. > > I agree with the concerns you raise around feature rot. For a feature like > EC, it'd be untenable to leave it in trunk-incompat since the rebases would > be impossible. I imagine we'd also need a very motivated maintainer (or > maintainers) to handle the periodic integration of new trunk commits, since > you'd potentially be doing it for multiple large features. If some brave > and experienced committer is willing to own maintenance of the > trunk-incompat branch, I think it could work. However, this is a big shift > from how we've historically done development. > If an incompatible feature is ready (like EC here), should we consider working towards the next major release? In other words, is it okay to defer cutting branch-3 until we have a large incompatible feature that would be a pain to keep up with? > > This is why I leaned toward Chris D's proposal, which is that we cut > branch-3 for 3.0.0-beta1, at which point trunk moves on to 4.0. In my mind, > this is the "default" proposal, since it's how we've previously done > things, with the slight adjustment that we defer cutting branch-3 until we > start enforcing compatibility. This is my current plan for the Hadoop 3 > series, and we already had a lot of +1's about releasing from trunk on the > previous thread. > I guess this makes sense. > > If there's a strong advocate for trunk-incompat over branch-3, let's have > that discussion. However, given that beta is still months (and multiple > releases) away, I don't think this decision affects my near-term goal of > getting 3.0.0-alpha1 released. > > Thanks, > Andrew >
Re: [DISCUSS] Increased use of feature branches
On Fri, Jun 10, 2016 at 9:39 PM, Karthik Kambatla wrote: > I would like to understand the trunk-incompat part of the proposal a > little better. > > Is trunk-incompat always going to be a superset of trunk? If yes, is it > just a change in naming convention with a hope that our approach to trunk > stability changes as Sangjin mentioned? > > Or, is it okay for trunk-incompat to be based off of an older commit in > trunk with (in)frequent rebases? This has the risk of incompatible changes > truly rotting. Periodic rebases will ensure these changes don't rot while > also easing the burden of hosting two branches; if we choose this route, > some guidance of the period and who rebases will be nice. > Based on my understanding from Vinod on the previous "Looking to..." thread, it would be the latter. The goal of trunk-incompat was to avoid adding yet-another-branch we need to commit to every time, compared to the branch-3 proposal. I agree with the concerns you raise around feature rot. For a feature like EC, it'd be untenable to leave it in trunk-incompat since the rebases would be impossible. I imagine we'd also need a very motivated maintainer (or maintainers) to handle the periodic integration of new trunk commits, since you'd potentially be doing it for multiple large features. If some brave and experienced committer is willing to own maintenance of the trunk-incompat branch, I think it could work. However, this is a big shift from how we've historically done development. This is why I leaned toward Chris D's proposal, which is that we cut branch-3 for 3.0.0-beta1, at which point trunk moves on to 4.0. In my mind, this is the "default" proposal, since it's how we've previously done things, with the slight adjustment that we defer cutting branch-3 until we start enforcing compatibility. This is my current plan for the Hadoop 3 series, and we already had a lot of +1's about releasing from trunk on the previous thread. If there's a strong advocate for trunk-incompat over branch-3, let's have that discussion. However, given that beta is still months (and multiple releases) away, I don't think this decision affects my near-term goal of getting 3.0.0-alpha1 released. Thanks, Andrew
Re: [DISCUSS] Increased use of feature branches
On Mon, Jun 13, 2016, at 12:41, Anu Engineer wrote: > Hi Colin, > > >Even if everyone used branches for all development, person X might merge > >their branch before person Y, forcing person Y to do a rebase or merge. > >It is not the presence of absence of branches that causes the need to > >merge or rebase, but the presence of absence of "churn." > > You are perfectly right on this technically. The issue is when a > branch developer gets caught in Commit, Revert, let-us-commit-again, > oh-it-is-not-fixed-completely, let-us-revert-the-revert cycle. > > I was hoping that branches will be exposed to less of this if everyone > had private branches and got some time to test and bake the feature > instead of just directly committing to trunk and then test. To be fair to developers, when something becomes problematic after it gets committed, it's usually because of something that didn't show up in testing on a private branch. For example, maybe unit tests fail occasionally with JDK7 instead of JDK8 (but the developer wasn't using JDK7, so how would he know?) Maybe there's a flaky test that shows up when the test machine is overloaded (but the developer's machine wasn't overloaded, so how would he see this?) Maybe there's some interaction with a new feature that just got added in trunk. And so on. > Once again, I agree with your point that in a perfect world, merges > should > be about the churn, but trunk is often treated as development branch, > So my point is that it gets unnecessary churn. I really appreciate the > thought in the thread - that is - let us be more responsible about how we > treat trunk. I think assuming that we will catch all bugs before branch merge is the "perfect world" view, and accepting that some of them will get through is the realistic view. Feature branch code will receive fewer test runs since it's not tested in every precommit build like trunk code is. I do agree that good and well-thought out tests should be a precondition of merging any big feature branch. But we have to expect that merges will be destabilizing in Hadoop, just like in every other software project out there. Trunk *is* a development branch, and should be treated as such. Not everything that hits trunk needs to immediately hit the stable branches. It's OK for there to be some experimentation, as long as developers make a strong effort to test things thoroughly and avoid flaky or time-dependent tests. > > > I thought the feature branch merge voting period had been shortened to 5 > >days rather than 7? We should probably spell this out on > >https://hadoop.apache.org/bylaws.html > > Thanks for the link, right now it says 7 days. That is why I assumed it > is 7. > Would you be kind enough to point me to a thread that says it is 5 days > for a merge Vote? > I did a google search, but was not able to find a thread like that. > Thanks in advance. Hmm, perhaps I was thinking of the release vote process. Can anyone confirm? It would be nice if this information could appear on the bylaws page... best, Colin > > Thanks > Anu > > > On 6/13/16, 11:51 AM, "Colin McCabe" wrote: > > >On Sun, Jun 12, 2016, at 05:06, Steve Loughran wrote: > >> > On 10 Jun 2016, at 20:37, Anu Engineer wrote: > >> > > >> > I actively work on two branches (Diskbalancer and ozone) and I agree > >> > with most of what Sangjin said. > >> > There is an overhead in working with branches, there are both technical > >> > costs and administrative issues > >> > which discourages developers from using branches. > >> > > >> > I think the biggest issue with branch based development is that fact > >> > that other developers do not use a branch. > >> > If a small feature appears as a series of commits to > >> > âÂÂâÂÂdatanode.javaâÂÂâÂÂ, the branch based developer ends > >> > up rebasing > >> > and paying this price of rebasing many times. If everyone followed a > >> > model of branch + Pull request, other branches > >> > would not have to deal with continues rebasing to trunk commits. If we > >> > are moving to a branch based > > > >Even if everyone used branches for all development, person X might merge > >their branch before person Y, forcing person Y to do a rebase or merge. > >It is not the presence of absence of branches that causes the need to > >merge or rebase, but the presence of absence of "churn." > > > >We try to minimize "churn" in many ways. For example, we discourage > >people from making trivial whitespace changes to parts of the code > >they're not modifying in their patch. Or doing things like letting > >their editor change the line ending of files from LF to CR/LF. However, > >in the final analysis, churn will always exist because development > >exists. > > > >> > development, we should probably move to that model for most development > >> > to avoid this tax on people who > >> > actually end up working in the branches. > >> > > >> > I do have a question in my mind though:
Re: [DISCUSS] Increased use of feature branches
On 6/13/16, 12:41 PM, "Anu Engineer" wrote: >Hi Colin, > >>Even if everyone used branches for all development, person X might merge >>their branch before person Y, forcing person Y to do a rebase or merge. >>It is not the presence of absence of branches that causes the need to >>merge or rebase, but the presence of absence of "churn." > >You are perfectly right on this technically. The issue is when a >branch developer gets caught in Commit, Revert, let-us-commit-again, >oh-it-is-not-fixed-completely, let-us-revert-the-revert cycle. > >I was hoping that branches will be exposed to less of this if everyone >had private branches and got some time to test and bake the feature >instead of just directly committing to trunk and then test. > >Once again, I agree with your point that in a perfect world, merges should >be about the churn, but trunk is often treated as development branch, >So my point is that it gets unnecessary churn. I really appreciate the >thought in the thread - that is - let us be more responsible about how we >treat trunk. > >> I thought the feature branch merge voting period had been shortened to 5 >>days rather than 7? We should probably spell this out on >>https://hadoop.apache.org/bylaws.html > >Thanks for the link, right now it says 7 days. That is why I assumed it >is 7. >Would you be kind enough to point me to a thread that says it is 5 days >for a merge Vote? >I did a google search, but was not able to find a thread like that. >Thanks in advance. I remember 5days voting was related to release. Not sure that time we discussed about branch merge voting time. Here is the link: http://mail-archives.apache.org/mod_mbox/hadoop-hdfs-dev/201406.mbox/%3C64A 2c234-dd6a-4e4c-b52d-e91d5d472...@hortonworks.com%3E > >Thanks >Anu > > >On 6/13/16, 11:51 AM, "Colin McCabe" wrote: > >>On Sun, Jun 12, 2016, at 05:06, Steve Loughran wrote: >>> > On 10 Jun 2016, at 20:37, Anu Engineer >>>wrote: >>> > >>> > I actively work on two branches (Diskbalancer and ozone) and I agree >>>with most of what Sangjin said. >>> > There is an overhead in working with branches, there are both >>>technical costs and administrative issues >>> > which discourages developers from using branches. >>> > >>> > I think the biggest issue with branch based development is that fact >>>that other developers do not use a branch. >>> > If a small feature appears as a series of commits to >>>ââdatanode.javaââ, the branch based developer ends up rebasing >>> > and paying this price of rebasing many times. If everyone followed a >>>model of branch + Pull request, other branches >>> > would not have to deal with continues rebasing to trunk commits. If >>>we are moving to a branch based >> >>Even if everyone used branches for all development, person X might merge >>their branch before person Y, forcing person Y to do a rebase or merge. >>It is not the presence of absence of branches that causes the need to >>merge or rebase, but the presence of absence of "churn." >> >>We try to minimize "churn" in many ways. For example, we discourage >>people from making trivial whitespace changes to parts of the code >>they're not modifying in their patch. Or doing things like letting >>their editor change the line ending of files from LF to CR/LF. However, >>in the final analysis, churn will always exist because development >>exists. >> >>> > development, we should probably move to that model for most >>>development to avoid this tax on people who >>> > actually end up working in the branches. >>> > >>> > I do have a question in my mind though: What is being proposed is >>>that we move active development to branches >>> > if the feature is small or incomplete, however keep the trunk open >>>for check-ins. One of the biggest reason why we >>> > check-in into trunk and not to branch-2 is because it is a change >>>that will break backward compatibility. So do we >>> > have an expectation of backward compatibility thru the 3.0-alpha >>>series (I personally vote No, since 3.0 is experimental >>> > at this stage), but if we decide to support some sort of >>>backward-compact then willy-nilly committing to trunk >>> > and still maintaining the expectation we can release Alphas from 3.0 >>>does not look possible. >>> > >>> > And then comes the question, once 3.0 becomes official, where do we >>>check-in a change, if that would break something? >>> > so this will lead us back to trunk being the unstable â 3.0 being >>>the new âbranch-2â. >> >>I'm not sure I really understand the goal of the "trunk-incompat" >>proposal. Like Karthik asked earlier in this thread, isn't it really >>just a rename of the existing trunk branch? >>It sounds like the policy is going to be exactly the same as now: >>incompatible stuff in trunk/trunk-incompat/whatever, 3.x compatible >>changes in the 3.x line, 2.x compatible changes in the 2.x line, etc. >>etc. >> >>I think we should just create branch-3 and follow the same policy we >>followed with branch-2
Re: [DISCUSS] Increased use of feature branches
Hi Colin, >Even if everyone used branches for all development, person X might merge >their branch before person Y, forcing person Y to do a rebase or merge. >It is not the presence of absence of branches that causes the need to >merge or rebase, but the presence of absence of "churn." You are perfectly right on this technically. The issue is when a branch developer gets caught in Commit, Revert, let-us-commit-again, oh-it-is-not-fixed-completely, let-us-revert-the-revert cycle. I was hoping that branches will be exposed to less of this if everyone had private branches and got some time to test and bake the feature instead of just directly committing to trunk and then test. Once again, I agree with your point that in a perfect world, merges should be about the churn, but trunk is often treated as development branch, So my point is that it gets unnecessary churn. I really appreciate the thought in the thread - that is - let us be more responsible about how we treat trunk. > I thought the feature branch merge voting period had been shortened to 5 >days rather than 7? We should probably spell this out on >https://hadoop.apache.org/bylaws.html Thanks for the link, right now it says 7 days. That is why I assumed it is 7. Would you be kind enough to point me to a thread that says it is 5 days for a merge Vote? I did a google search, but was not able to find a thread like that. Thanks in advance. Thanks Anu On 6/13/16, 11:51 AM, "Colin McCabe" wrote: >On Sun, Jun 12, 2016, at 05:06, Steve Loughran wrote: >> > On 10 Jun 2016, at 20:37, Anu Engineer wrote: >> > >> > I actively work on two branches (Diskbalancer and ozone) and I agree with >> > most of what Sangjin said. >> > There is an overhead in working with branches, there are both technical >> > costs and administrative issues >> > which discourages developers from using branches. >> > >> > I think the biggest issue with branch based development is that fact that >> > other developers do not use a branch. >> > If a small feature appears as a series of commits to >> > ââdatanode.javaââ, the branch based developer ends up rebasing >> > and paying this price of rebasing many times. If everyone followed a model >> > of branch + Pull request, other branches >> > would not have to deal with continues rebasing to trunk commits. If we are >> > moving to a branch based > >Even if everyone used branches for all development, person X might merge >their branch before person Y, forcing person Y to do a rebase or merge. >It is not the presence of absence of branches that causes the need to >merge or rebase, but the presence of absence of "churn." > >We try to minimize "churn" in many ways. For example, we discourage >people from making trivial whitespace changes to parts of the code >they're not modifying in their patch. Or doing things like letting >their editor change the line ending of files from LF to CR/LF. However, >in the final analysis, churn will always exist because development >exists. > >> > development, we should probably move to that model for most development to >> > avoid this tax on people who >> > actually end up working in the branches. >> > >> > I do have a question in my mind though: What is being proposed is that we >> > move active development to branches >> > if the feature is small or incomplete, however keep the trunk open for >> > check-ins. One of the biggest reason why we >> > check-in into trunk and not to branch-2 is because it is a change that >> > will break backward compatibility. So do we >> > have an expectation of backward compatibility thru the 3.0-alpha series (I >> > personally vote No, since 3.0 is experimental >> > at this stage), but if we decide to support some sort of backward-compact >> > then willy-nilly committing to trunk >> > and still maintaining the expectation we can release Alphas from 3.0 does >> > not look possible. >> > >> > And then comes the question, once 3.0 becomes official, where do we >> > check-in a change, if that would break something? >> > so this will lead us back to trunk being the unstable â 3.0 being the >> > new âbranch-2â. > >I'm not sure I really understand the goal of the "trunk-incompat" >proposal. Like Karthik asked earlier in this thread, isn't it really >just a rename of the existing trunk branch? >It sounds like the policy is going to be exactly the same as now: >incompatible stuff in trunk/trunk-incompat/whatever, 3.x compatible >changes in the 3.x line, 2.x compatible changes in the 2.x line, etc. >etc. > >I think we should just create branch-3 and follow the same policy we >followed with branch-2 and branch-1. Switching around the names doesn't >really change the policy, and it creates confusion since it's >inconsistent with what we did earlier. > >I think one of the big frustrations with trunk is that features sat >there a while without being released because they weren't compatible >with branch-2-- the shell script
Re: [DISCUSS] Increased use of feature branches
On Sun, Jun 12, 2016, at 05:06, Steve Loughran wrote: > > On 10 Jun 2016, at 20:37, Anu Engineer wrote: > > > > I actively work on two branches (Diskbalancer and ozone) and I agree with > > most of what Sangjin said. > > There is an overhead in working with branches, there are both technical > > costs and administrative issues > > which discourages developers from using branches. > > > > I think the biggest issue with branch based development is that fact that > > other developers do not use a branch. > > If a small feature appears as a series of commits to > > ââdatanode.javaââ, the branch based developer ends up rebasing > > and paying this price of rebasing many times. If everyone followed a model > > of branch + Pull request, other branches > > would not have to deal with continues rebasing to trunk commits. If we are > > moving to a branch based Even if everyone used branches for all development, person X might merge their branch before person Y, forcing person Y to do a rebase or merge. It is not the presence of absence of branches that causes the need to merge or rebase, but the presence of absence of "churn." We try to minimize "churn" in many ways. For example, we discourage people from making trivial whitespace changes to parts of the code they're not modifying in their patch. Or doing things like letting their editor change the line ending of files from LF to CR/LF. However, in the final analysis, churn will always exist because development exists. > > development, we should probably move to that model for most development to > > avoid this tax on people who > > actually end up working in the branches. > > > > I do have a question in my mind though: What is being proposed is that we > > move active development to branches > > if the feature is small or incomplete, however keep the trunk open for > > check-ins. One of the biggest reason why we > > check-in into trunk and not to branch-2 is because it is a change that will > > break backward compatibility. So do we > > have an expectation of backward compatibility thru the 3.0-alpha series (I > > personally vote No, since 3.0 is experimental > > at this stage), but if we decide to support some sort of backward-compact > > then willy-nilly committing to trunk > > and still maintaining the expectation we can release Alphas from 3.0 does > > not look possible. > > > > And then comes the question, once 3.0 becomes official, where do we > > check-in a change, if that would break something? > > so this will lead us back to trunk being the unstable â 3.0 being the new > > âbranch-2â. I'm not sure I really understand the goal of the "trunk-incompat" proposal. Like Karthik asked earlier in this thread, isn't it really just a rename of the existing trunk branch? It sounds like the policy is going to be exactly the same as now: incompatible stuff in trunk/trunk-incompat/whatever, 3.x compatible changes in the 3.x line, 2.x compatible changes in the 2.x line, etc. etc. I think we should just create branch-3 and follow the same policy we followed with branch-2 and branch-1. Switching around the names doesn't really change the policy, and it creates confusion since it's inconsistent with what we did earlier. I think one of the big frustrations with trunk is that features sat there a while without being released because they weren't compatible with branch-2-- the shell script rewrite, for example. However, this reflects a fundamental tradeoff-- either incompatible features can't be developed at all in the lifetime of Hadoop 3.x, or we will need somewhere to put them. The trunk-incompat proposal is like saying that you've solved the prison overcrowding problem by renaming all prisons to "correctional facilities." > > > > One more point: If we are moving to use a branch always â then we are > > looking at a model similar to using a git + pull > > request model. If that is so would it make sense to modify the rules to > > make these branches easier to merge? > > Say for example, if all commits in a branch has followed review and > > checking policy â just like trunk and commits > > have been made only after a sign off from a committer, would it be possible > > to merge with a 3-day voting period > > instead of 7, or treat it just like todayâs commit to trunk â but with > > 2 people signing-off? I thought the feature branch merge voting period had been shortened to 5 days rather than 7? We should probably spell this out on https://hadoop.apache.org/bylaws.html . Like I said above, I don't believe that *all* development should be on feature branches, just biggish stuff that is likely to be controversial and/or disruptive. The suggestion I made earlier is that if 3 people ask you for a branch, you should definitely strongly consider a branch. I do think we should shorten the voting period for adding new branch committers... making it 3 or 4 days would be fine. After all, the work of br
Re: [DISCUSS] Increased use of feature branches
> On 10 Jun 2016, at 20:37, Anu Engineer wrote: > > I actively work on two branches (Diskbalancer and ozone) and I agree with > most of what Sangjin said. > There is an overhead in working with branches, there are both technical costs > and administrative issues > which discourages developers from using branches. > > I think the biggest issue with branch based development is that fact that > other developers do not use a branch. > If a small feature appears as a series of commits to “”datanode.java””, the > branch based developer ends up rebasing > and paying this price of rebasing many times. If everyone followed a model of > branch + Pull request, other branches > would not have to deal with continues rebasing to trunk commits. If we are > moving to a branch based > development, we should probably move to that model for most development to > avoid this tax on people who > actually end up working in the branches. > > I do have a question in my mind though: What is being proposed is that we > move active development to branches > if the feature is small or incomplete, however keep the trunk open for > check-ins. One of the biggest reason why we > check-in into trunk and not to branch-2 is because it is a change that will > break backward compatibility. So do we > have an expectation of backward compatibility thru the 3.0-alpha series (I > personally vote No, since 3.0 is experimental > at this stage), but if we decide to support some sort of backward-compact > then willy-nilly committing to trunk > and still maintaining the expectation we can release Alphas from 3.0 does not > look possible. > > And then comes the question, once 3.0 becomes official, where do we check-in > a change, if that would break something? > so this will lead us back to trunk being the unstable – 3.0 being the new > “branch-2”. > > One more point: If we are moving to use a branch always – then we are looking > at a model similar to using a git + pull > request model. If that is so would it make sense to modify the rules to make > these branches easier to merge? > Say for example, if all commits in a branch has followed review and checking > policy – just like trunk and commits > have been made only after a sign off from a committer, would it be possible > to merge with a 3-day voting period > instead of 7, or treat it just like today’s commit to trunk – but with 2 > people signing-off? > > What I am suggesting is reducing the administrative overheads of using a > branch to encourage use of branching. > Right now it feels like Apache’s process encourages committing directly to > trunk than a branch > > Thanks > Anu It's a per project process. In slider, we've used a git flow: all work goes in a feature branch, then merge in with a merge point. This gives a better history of workflow, as an individual body of work is an ordered sequence of operations, independent of everything else. This makes cherry picking a sequence easier, it even makes unrolling a series of changes easier: until the entire set of changes is committed, there is nothing to back out. 1. there's the rebase/merge problem: coping with conflicting change. Rebasing helps, but makes team dev complex. And, if there are big conflict changes, its often easier to take the current diff with trunk branch and reapply it than try to rebase a sequence of operations. You don't always need to rebase though; an FB can repeatedly merge in trunk, for a history which may not be self contained, but does isolate the feature dev from everyone else's work. 2. Changes don't get exposed more broadly until the feature is in. That may reduce review, but for those of us who work on downstream code it means: nothing breaks until the complete feature is in. You may not realise it, but those of us who do compile downstream things (slider, spark) against even branch-2 always fear discovering what's just broken at the API level alone. And that's "the stable branch". I haven't dared build against trunk for a while. 3. It's a real PITA trying to do development which spans >1 feature branch. Even today it's tricky with code spanning >1 patch (HADOOP-13207 and HADOP-13208 this weekend). There I'm working in one branch and generating two separate patches. That's hard to do in a single feature branch., 4. The rules for feature branch merge. If I get a patch into trunk, it's in the codebase. If I get it into a feature branch, there's the risk the entire feature branch doesn't get in. Fix: for short lived feature branches, we have an RTC policy strict enough we can say "if a feature branch commit is in. it's considered good enough, even if a few more successor commits are required before the whole sequence of commits are considered stable. 5. If you do lots of incremental patches (as feature branches encourage), the patch history gets very noisy. Maybe here the patches can be rolled up for the final commit. This is how Spark work
Re: [DISCUSS] Increased use of feature branches
ot;. Even if we release from the >>> trunk, if >>> >our bar for merging to trunk is low, the quality will not improve >>> >automatically. So I think we ought to tackle the quality question first. >>> > >>> >My 2 cents. >>> > >>> > >>> >On Fri, Jun 10, 2016 at 8:57 AM, Zhe Zhang wrote: >>> > >>> >> Thanks for the notes Andrew, Junping, Karthik. >>> >> >>> >> Here are some of my understandings: >>> >> >>> >> - Trunk is the "latest and greatest" of Hadoop. If a user starts using >>> >> Hadoop today, without legacy workloads, trunk is what he/she should >>> use. >>> >> - Therefore, each commit to trunk should be transactional -- atomic, >>> >> consistent, isolated (from other uncommitted patches); I'm not so sure >>> >> about durability, Hadoop might be gone in 50 years :). As a >>> committer, I >>> >> should be able to look at a patch and determine whether it's a >>> >> self-contained improvement of trunk, without looking at other >>> uncommitted >>> >> patches. >>> >> - Some comments inline: >>> >> >>> >> On Fri, Jun 10, 2016 at 6:56 AM Junping Du >>> wrote: >>> >> >>> >> > Comparing with advantages, I believe the disadvantages of shipping >>> any >>> >> > releases directly from trunk are more obvious and significant: >>> >> > - A lot of commits (incompatible, risky, uncompleted feature, etc.) >>> have >>> >> > to wait to commit to trunk or put into a separated branch that could >>> >> delay >>> >> > feature development progress as additional vote process get >>> involved even >>> >> > the feature is simple and harmless. >>> >> > >>> >> Thanks Junping, those are valid concerns. I think we should clearly >>> >> separate incompatible with uncompleted / half-done work in this >>> >> discussion. Whether people should commit incompatible changes to >>> trunk is a >>> >> much more tricky question (related to trunk-incompat etc.). But per my >>> >> comment above, IMHO, *not committing uncompleted work to trunk* >>> should be a >>> >> much easier principle to agree upon. >>> >> >>> >> >>> >> > - For small feature with only 1 or 2 commits, that need three +1 >>> from >>> >> PMCs >>> >> > will increase the bar largely for contributors who just start to >>> >> contribute >>> >> > on Hadoop features but no such sufficient support. >>> >> > >>> >> Development overhead is another valid concern. I think our >>> rule-of-thumb >>> >> should be that, small-medium new features should be proposed as a >>> single >>> >> JIRA/patch (as we recently did for HADOOP-12666). If the complexity >>> goes >>> >> beyond a single JIRA/patch, use a feature branch. >>> >> >>> >> >>> >> > >>> >> > Given these concerns, I am open to other options, like: proposed by >>> Vinod >>> >> > or Chris, but rather than to release anything directly from trunk. >>> >> > >>> >> > - This point doesn't necessarily need to be resolved now though, >>> since >>> >> > again we're still doing alphas. >>> >> > No. I think we have to settle down this first. Without a common >>> agreed >>> >> and >>> >> > transparent release process and branches in community, any release >>> >> (alpha, >>> >> > beta) bits is only called a private release but not a official >>> apache >>> >> > hadoop release (even alpha). >>> >> > >>> >> > >>> >> > Thanks, >>> >> > >>> >> > Junping >>> >> > >>> >> > From: Karthik Kambatla >>> >> > Sent: Friday, June 10, 2016 7:49 AM >>> >> > To: Andrew Wang >>> >> > Cc: common-...@hadoop.apache.org; hdfs-dev@hadoop.apache.org; >>> >> > mapreduce-...@hadoop.apache.org; yarn-...@hadoop.apache.org >>> >> > Subject: Re: [DISCUSS] Incre
Re: [DISCUSS] Increased use of feature branches
the disadvantages of shipping >> any >> >> > releases directly from trunk are more obvious and significant: >> >> > - A lot of commits (incompatible, risky, uncompleted feature, etc.) >> have >> >> > to wait to commit to trunk or put into a separated branch that could >> >> delay >> >> > feature development progress as additional vote process get involved >> even >> >> > the feature is simple and harmless. >> >> > >> >> Thanks Junping, those are valid concerns. I think we should clearly >> >> separate incompatible with uncompleted / half-done work in this >> >> discussion. Whether people should commit incompatible changes to trunk >> is a >> >> much more tricky question (related to trunk-incompat etc.). But per my >> >> comment above, IMHO, *not committing uncompleted work to trunk* should >> be a >> >> much easier principle to agree upon. >> >> >> >> >> >> > - For small feature with only 1 or 2 commits, that need three +1 from >> >> PMCs >> >> > will increase the bar largely for contributors who just start to >> >> contribute >> >> > on Hadoop features but no such sufficient support. >> >> > >> >> Development overhead is another valid concern. I think our >> rule-of-thumb >> >> should be that, small-medium new features should be proposed as a >> single >> >> JIRA/patch (as we recently did for HADOOP-12666). If the complexity >> goes >> >> beyond a single JIRA/patch, use a feature branch. >> >> >> >> >> >> > >> >> > Given these concerns, I am open to other options, like: proposed by >> Vinod >> >> > or Chris, but rather than to release anything directly from trunk. >> >> > >> >> > - This point doesn't necessarily need to be resolved now though, >> since >> >> > again we're still doing alphas. >> >> > No. I think we have to settle down this first. Without a common >> agreed >> >> and >> >> > transparent release process and branches in community, any release >> >> (alpha, >> >> > beta) bits is only called a private release but not a official apache >> >> > hadoop release (even alpha). >> >> > >> >> > >> >> > Thanks, >> >> > >> >> > Junping >> >> > >> >> > From: Karthik Kambatla >> >> > Sent: Friday, June 10, 2016 7:49 AM >> >> > To: Andrew Wang >> >> > Cc: common-...@hadoop.apache.org; hdfs-dev@hadoop.apache.org; >> >> > mapreduce-...@hadoop.apache.org; yarn-...@hadoop.apache.org >> >> > Subject: Re: [DISCUSS] Increased use of feature branches >> >> > >> >> > Thanks for restarting this thread Andrew. I really hope we can get >> this >> >> > across to a VOTE so it is clear. >> >> > >> >> > I see a few advantages shipping from trunk: >> >> > >> >> >- The lack of need for one additional backport each time. >> >> >- Feature rot in trunk >> >> > >> >> > Instead of creating branch-3, I recommend creating branch-3.x so we >> can >> >> > continue doing 3.x releases off branch-3 even after we move trunk to >> 4.x >> >> (I >> >> > said it :)) >> >> > >> >> > On Thu, Jun 9, 2016 at 11:12 PM, Andrew Wang < >> andrew.w...@cloudera.com> >> >> > wrote: >> >> > >> >> > > Hi all, >> >> > > >> >> > > On a separate thread, a question was raised about 3.x branching >> and use >> >> > of >> >> > > feature branches going forward. >> >> > > >> >> > > We discussed this previously on the "Looking to a Hadoop 3 release" >> >> > thread >> >> > > that has spanned the years, with Vinod making this proposal >> (building >> >> on >> >> > > ideas from others who also commented in the email thread): >> >> > > >> >> > > >> >> > > >> >> > >> >> >> http://mail-archives.apache.org/mod_mbox/hadoop-common-dev/201604.mbox/browser >> >> > > >> >> > > Pasting here for ease: >> >> > > >> >> > > On an unrelated note, offline I was pitching to a bunch of >> >> > > contributors another idea to deal >> >> > > with rotting trunk post 3.x: *Make 3.x releases off of trunk >> directly*. >> >> > > >> >> > > What this gains us is that >> >> > > - Trunk is always nearly stable or nearly ready for releases >> >> > > - We no longer have some code lying around in some branch (today’s >> >> > > trunk) that is not releasable >> >> > > because it gets mixed with other undesirable and incompatible >> changes. >> >> > > - This needs to be coupled with more discipline on individual >> >> > > features - medium to to large >> >> > > features are always worked upon in branches and get merged into >> trunk >> >> > > (and a nearing release!) >> >> > > when they are ready >> >> > > - All incompatible changes go into some sort of a trunk-incompat >> >> > > branch and stay there till >> >> > > we accumulate enough of those to warrant another major release. >> >> > > >> >> > > Regarding "trunk-incompat", since we're still in the alpha stage >> for >> >> > 3.0.0, >> >> > > there's no need for this branch yet. This aspect of Vinod's >> proposal >> >> was >> >> > > still under a bit of discussion; Chris Douglas though we should >> cut a >> >> > > branch-3 for the first 3.0.0 beta, which aligns with my original >> >> > thinking. >> >> > > This point doesn't necessarily need to be resolved now though, >> since >> >> > again >> >> > > we're still doing alphas. >> >> > > >> >> > > What we should get consensus on is the goal of keeping trunk >> stable, >> >> and >> >> > > achieving that by doing more development on feature branches and >> being >> >> > > judicious about merges. My sense from the Hadoop 3 email thread >> (and >> >> the >> >> > > more recent one on the async API) is that people are generally in >> favor >> >> > of >> >> > > this. >> >> > > >> >> > > We're just about ready to do the first 3.0.0 alpha, so would >> greatly >> >> > > appreciate everyone's timely response in this matter. >> >> > > >> >> > > Thanks, >> >> > > Andrew >> >> > > >> >> > >> >> > - >> >> > To unsubscribe, e-mail: common-dev-unsubscr...@hadoop.apache.org >> >> > For additional commands, e-mail: common-dev-h...@hadoop.apache.org >> >> > >> >> > >> >> >> >> >
Re: [DISCUSS] Increased use of feature branches
> >unscientific suggestion may be if a feature takes more than dozen commits > >and longer than a month, we should probably have a bias towards a feature > >branch. > > > >Branch-based development also makes you go faster if your feature is > >larger. I wouldn't do it the other way for timeline service v.2 for > example. > > > >That said, feature branches don't come for free. Now the onus is on the > >feature developer to constantly rebase with the trunk to keep it > reasonably > >integrated with the trunk. More logistics is involved for the feature > >developer. Another big question is, when a feature branch gets big and > it's > >time to merge, would it get as scrutinized as a series of individual > >commits? Since the size of merge can be big, you kind of have to rely on > >those feature committers and those who help them. > > > >In terms of integrating/stabilizing, I don't think branch development > >necessarily makes it harder. It is again granularity. In case of direct > >commits on trunk, you do a lot more fine-grained integrations. In case of > >branch development, you do far fewer coarse-grained integrations via > >rebasing. If more people are doing branch-based development, it makes > >rebasing easier to manage too. > > > >Going back to the related topic of where to release (trunk v. branch-X), I > >think that is more of a proxy of the real question of "how do we maintain > >quality and stability of the trunk?". Even if we release from the trunk, > if > >our bar for merging to trunk is low, the quality will not improve > >automatically. So I think we ought to tackle the quality question first. > > > >My 2 cents. > > > > > >On Fri, Jun 10, 2016 at 8:57 AM, Zhe Zhang wrote: > > > >> Thanks for the notes Andrew, Junping, Karthik. > >> > >> Here are some of my understandings: > >> > >> - Trunk is the "latest and greatest" of Hadoop. If a user starts using > >> Hadoop today, without legacy workloads, trunk is what he/she should use. > >> - Therefore, each commit to trunk should be transactional -- atomic, > >> consistent, isolated (from other uncommitted patches); I'm not so sure > >> about durability, Hadoop might be gone in 50 years :). As a committer, I > >> should be able to look at a patch and determine whether it's a > >> self-contained improvement of trunk, without looking at other > uncommitted > >> patches. > >> - Some comments inline: > >> > >> On Fri, Jun 10, 2016 at 6:56 AM Junping Du wrote: > >> > >> > Comparing with advantages, I believe the disadvantages of shipping any > >> > releases directly from trunk are more obvious and significant: > >> > - A lot of commits (incompatible, risky, uncompleted feature, etc.) > have > >> > to wait to commit to trunk or put into a separated branch that could > >> delay > >> > feature development progress as additional vote process get involved > even > >> > the feature is simple and harmless. > >> > > >> Thanks Junping, those are valid concerns. I think we should clearly > >> separate incompatible with uncompleted / half-done work in this > >> discussion. Whether people should commit incompatible changes to trunk > is a > >> much more tricky question (related to trunk-incompat etc.). But per my > >> comment above, IMHO, *not committing uncompleted work to trunk* should > be a > >> much easier principle to agree upon. > >> > >> > >> > - For small feature with only 1 or 2 commits, that need three +1 from > >> PMCs > >> > will increase the bar largely for contributors who just start to > >> contribute > >> > on Hadoop features but no such sufficient support. > >> > > >> Development overhead is another valid concern. I think our rule-of-thumb > >> should be that, small-medium new features should be proposed as a single > >> JIRA/patch (as we recently did for HADOOP-12666). If the complexity goes > >> beyond a single JIRA/patch, use a feature branch. > >> > >> > >> > > >> > Given these concerns, I am open to other options, like: proposed by > Vinod > >> > or Chris, but rather than to release anything directly from trunk. > >> > > >> > - This point doesn't necessarily need to be resolved now though, since > >> > again we're still doing alphas. > >> > No. I think
Re: [DISCUSS] Increased use of feature branches
t;automatically. So I think we ought to tackle the quality question first. > >My 2 cents. > > >On Fri, Jun 10, 2016 at 8:57 AM, Zhe Zhang wrote: > >> Thanks for the notes Andrew, Junping, Karthik. >> >> Here are some of my understandings: >> >> - Trunk is the "latest and greatest" of Hadoop. If a user starts using >> Hadoop today, without legacy workloads, trunk is what he/she should use. >> - Therefore, each commit to trunk should be transactional -- atomic, >> consistent, isolated (from other uncommitted patches); I'm not so sure >> about durability, Hadoop might be gone in 50 years :). As a committer, I >> should be able to look at a patch and determine whether it's a >> self-contained improvement of trunk, without looking at other uncommitted >> patches. >> - Some comments inline: >> >> On Fri, Jun 10, 2016 at 6:56 AM Junping Du wrote: >> >> > Comparing with advantages, I believe the disadvantages of shipping any >> > releases directly from trunk are more obvious and significant: >> > - A lot of commits (incompatible, risky, uncompleted feature, etc.) have >> > to wait to commit to trunk or put into a separated branch that could >> delay >> > feature development progress as additional vote process get involved even >> > the feature is simple and harmless. >> > >> Thanks Junping, those are valid concerns. I think we should clearly >> separate incompatible with uncompleted / half-done work in this >> discussion. Whether people should commit incompatible changes to trunk is a >> much more tricky question (related to trunk-incompat etc.). But per my >> comment above, IMHO, *not committing uncompleted work to trunk* should be a >> much easier principle to agree upon. >> >> >> > - For small feature with only 1 or 2 commits, that need three +1 from >> PMCs >> > will increase the bar largely for contributors who just start to >> contribute >> > on Hadoop features but no such sufficient support. >> > >> Development overhead is another valid concern. I think our rule-of-thumb >> should be that, small-medium new features should be proposed as a single >> JIRA/patch (as we recently did for HADOOP-12666). If the complexity goes >> beyond a single JIRA/patch, use a feature branch. >> >> >> > >> > Given these concerns, I am open to other options, like: proposed by Vinod >> > or Chris, but rather than to release anything directly from trunk. >> > >> > - This point doesn't necessarily need to be resolved now though, since >> > again we're still doing alphas. >> > No. I think we have to settle down this first. Without a common agreed >> and >> > transparent release process and branches in community, any release >> (alpha, >> > beta) bits is only called a private release but not a official apache >> > hadoop release (even alpha). >> > >> > >> > Thanks, >> > >> > Junping >> > >> > From: Karthik Kambatla >> > Sent: Friday, June 10, 2016 7:49 AM >> > To: Andrew Wang >> > Cc: common-...@hadoop.apache.org; hdfs-dev@hadoop.apache.org; >> > mapreduce-...@hadoop.apache.org; yarn-...@hadoop.apache.org >> > Subject: Re: [DISCUSS] Increased use of feature branches >> > >> > Thanks for restarting this thread Andrew. I really hope we can get this >> > across to a VOTE so it is clear. >> > >> > I see a few advantages shipping from trunk: >> > >> >- The lack of need for one additional backport each time. >> >- Feature rot in trunk >> > >> > Instead of creating branch-3, I recommend creating branch-3.x so we can >> > continue doing 3.x releases off branch-3 even after we move trunk to 4.x >> (I >> > said it :)) >> > >> > On Thu, Jun 9, 2016 at 11:12 PM, Andrew Wang >> > wrote: >> > >> > > Hi all, >> > > >> > > On a separate thread, a question was raised about 3.x branching and use >> > of >> > > feature branches going forward. >> > > >> > > We discussed this previously on the "Looking to a Hadoop 3 release" >> > thread >> > > that has spanned the years, with Vinod making this proposal (building >> on >> > > ideas from others who also commented in the email thread): >> > > >> > > >> > > >> > >> http://mail-archive
Re: [DISCUSS] Increased use of feature branches
> transparent release process and branches in community, any release > (alpha, > > beta) bits is only called a private release but not a official apache > > hadoop release (even alpha). > > > > > > Thanks, > > > > Junping > > > > From: Karthik Kambatla > > Sent: Friday, June 10, 2016 7:49 AM > > To: Andrew Wang > > Cc: common-...@hadoop.apache.org; hdfs-dev@hadoop.apache.org; > > mapreduce-...@hadoop.apache.org; yarn-...@hadoop.apache.org > > Subject: Re: [DISCUSS] Increased use of feature branches > > > > Thanks for restarting this thread Andrew. I really hope we can get this > > across to a VOTE so it is clear. > > > > I see a few advantages shipping from trunk: > > > >- The lack of need for one additional backport each time. > >- Feature rot in trunk > > > > Instead of creating branch-3, I recommend creating branch-3.x so we can > > continue doing 3.x releases off branch-3 even after we move trunk to 4.x > (I > > said it :)) > > > > On Thu, Jun 9, 2016 at 11:12 PM, Andrew Wang > > wrote: > > > > > Hi all, > > > > > > On a separate thread, a question was raised about 3.x branching and use > > of > > > feature branches going forward. > > > > > > We discussed this previously on the "Looking to a Hadoop 3 release" > > thread > > > that has spanned the years, with Vinod making this proposal (building > on > > > ideas from others who also commented in the email thread): > > > > > > > > > > > > http://mail-archives.apache.org/mod_mbox/hadoop-common-dev/201604.mbox/browser > > > > > > Pasting here for ease: > > > > > > On an unrelated note, offline I was pitching to a bunch of > > > contributors another idea to deal > > > with rotting trunk post 3.x: *Make 3.x releases off of trunk directly*. > > > > > > What this gains us is that > > > - Trunk is always nearly stable or nearly ready for releases > > > - We no longer have some code lying around in some branch (today’s > > > trunk) that is not releasable > > > because it gets mixed with other undesirable and incompatible changes. > > > - This needs to be coupled with more discipline on individual > > > features - medium to to large > > > features are always worked upon in branches and get merged into trunk > > > (and a nearing release!) > > > when they are ready > > > - All incompatible changes go into some sort of a trunk-incompat > > > branch and stay there till > > > we accumulate enough of those to warrant another major release. > > > > > > Regarding "trunk-incompat", since we're still in the alpha stage for > > 3.0.0, > > > there's no need for this branch yet. This aspect of Vinod's proposal > was > > > still under a bit of discussion; Chris Douglas though we should cut a > > > branch-3 for the first 3.0.0 beta, which aligns with my original > > thinking. > > > This point doesn't necessarily need to be resolved now though, since > > again > > > we're still doing alphas. > > > > > > What we should get consensus on is the goal of keeping trunk stable, > and > > > achieving that by doing more development on feature branches and being > > > judicious about merges. My sense from the Hadoop 3 email thread (and > the > > > more recent one on the async API) is that people are generally in favor > > of > > > this. > > > > > > We're just about ready to do the first 3.0.0 alpha, so would greatly > > > appreciate everyone's timely response in this matter. > > > > > > Thanks, > > > Andrew > > > > > > > - > > To unsubscribe, e-mail: common-dev-unsubscr...@hadoop.apache.org > > For additional commands, e-mail: common-dev-h...@hadoop.apache.org > > > > >
Re: [DISCUSS] Increased use of feature branches
Thanks for the notes Andrew, Junping, Karthik. Here are some of my understandings: - Trunk is the "latest and greatest" of Hadoop. If a user starts using Hadoop today, without legacy workloads, trunk is what he/she should use. - Therefore, each commit to trunk should be transactional -- atomic, consistent, isolated (from other uncommitted patches); I'm not so sure about durability, Hadoop might be gone in 50 years :). As a committer, I should be able to look at a patch and determine whether it's a self-contained improvement of trunk, without looking at other uncommitted patches. - Some comments inline: On Fri, Jun 10, 2016 at 6:56 AM Junping Du wrote: > Comparing with advantages, I believe the disadvantages of shipping any > releases directly from trunk are more obvious and significant: > - A lot of commits (incompatible, risky, uncompleted feature, etc.) have > to wait to commit to trunk or put into a separated branch that could delay > feature development progress as additional vote process get involved even > the feature is simple and harmless. > Thanks Junping, those are valid concerns. I think we should clearly separate incompatible with uncompleted / half-done work in this discussion. Whether people should commit incompatible changes to trunk is a much more tricky question (related to trunk-incompat etc.). But per my comment above, IMHO, *not committing uncompleted work to trunk* should be a much easier principle to agree upon. > - For small feature with only 1 or 2 commits, that need three +1 from PMCs > will increase the bar largely for contributors who just start to contribute > on Hadoop features but no such sufficient support. > Development overhead is another valid concern. I think our rule-of-thumb should be that, small-medium new features should be proposed as a single JIRA/patch (as we recently did for HADOOP-12666). If the complexity goes beyond a single JIRA/patch, use a feature branch. > > Given these concerns, I am open to other options, like: proposed by Vinod > or Chris, but rather than to release anything directly from trunk. > > - This point doesn't necessarily need to be resolved now though, since > again we're still doing alphas. > No. I think we have to settle down this first. Without a common agreed and > transparent release process and branches in community, any release (alpha, > beta) bits is only called a private release but not a official apache > hadoop release (even alpha). > > > Thanks, > > Junping > > From: Karthik Kambatla > Sent: Friday, June 10, 2016 7:49 AM > To: Andrew Wang > Cc: common-...@hadoop.apache.org; hdfs-dev@hadoop.apache.org; > mapreduce-...@hadoop.apache.org; yarn-...@hadoop.apache.org > Subject: Re: [DISCUSS] Increased use of feature branches > > Thanks for restarting this thread Andrew. I really hope we can get this > across to a VOTE so it is clear. > > I see a few advantages shipping from trunk: > >- The lack of need for one additional backport each time. >- Feature rot in trunk > > Instead of creating branch-3, I recommend creating branch-3.x so we can > continue doing 3.x releases off branch-3 even after we move trunk to 4.x (I > said it :)) > > On Thu, Jun 9, 2016 at 11:12 PM, Andrew Wang > wrote: > > > Hi all, > > > > On a separate thread, a question was raised about 3.x branching and use > of > > feature branches going forward. > > > > We discussed this previously on the "Looking to a Hadoop 3 release" > thread > > that has spanned the years, with Vinod making this proposal (building on > > ideas from others who also commented in the email thread): > > > > > > > http://mail-archives.apache.org/mod_mbox/hadoop-common-dev/201604.mbox/browser > > > > Pasting here for ease: > > > > On an unrelated note, offline I was pitching to a bunch of > > contributors another idea to deal > > with rotting trunk post 3.x: *Make 3.x releases off of trunk directly*. > > > > What this gains us is that > > - Trunk is always nearly stable or nearly ready for releases > > - We no longer have some code lying around in some branch (today’s > > trunk) that is not releasable > > because it gets mixed with other undesirable and incompatible changes. > > - This needs to be coupled with more discipline on individual > > features - medium to to large > > features are always worked upon in branches and get merged into trunk > > (and a nearing release!) > > when they are ready > > - All incompatible changes go into some sort of a trunk-incompat > > branch and stay there till > > we accumulate enough of those to warrant another major rel
Re: [DISCUSS] Increased use of feature branches
June 10, 2016 7:49 AM > To: Andrew Wang > Cc: common-...@hadoop.apache.org; hdfs-dev@hadoop.apache.org; > mapreduce-...@hadoop.apache.org; yarn-...@hadoop.apache.org > Subject: Re: [DISCUSS] Increased use of feature branches > > Thanks for restarting this thread Andrew. I really hope we can get this > across to a VOTE so it is clear. > > I see a few advantages shipping from trunk: > >- The lack of need for one additional backport each time. >- Feature rot in trunk > > Instead of creating branch-3, I recommend creating branch-3.x so we can > continue doing 3.x releases off branch-3 even after we move trunk to 4.x (I > said it :)) > > On Thu, Jun 9, 2016 at 11:12 PM, Andrew Wang > wrote: > > > Hi all, > > > > On a separate thread, a question was raised about 3.x branching and use > of > > feature branches going forward. > > > > We discussed this previously on the "Looking to a Hadoop 3 release" > thread > > that has spanned the years, with Vinod making this proposal (building on > > ideas from others who also commented in the email thread): > > > > > > > http://mail-archives.apache.org/mod_mbox/hadoop-common-dev/201604.mbox/browser > > > > Pasting here for ease: > > > > On an unrelated note, offline I was pitching to a bunch of > > contributors another idea to deal > > with rotting trunk post 3.x: *Make 3.x releases off of trunk directly*. > > > > What this gains us is that > > - Trunk is always nearly stable or nearly ready for releases > > - We no longer have some code lying around in some branch (today’s > > trunk) that is not releasable > > because it gets mixed with other undesirable and incompatible changes. > > - This needs to be coupled with more discipline on individual > > features - medium to to large > > features are always worked upon in branches and get merged into trunk > > (and a nearing release!) > > when they are ready > > - All incompatible changes go into some sort of a trunk-incompat > > branch and stay there till > > we accumulate enough of those to warrant another major release. > > > > Regarding "trunk-incompat", since we're still in the alpha stage for > 3.0.0, > > there's no need for this branch yet. This aspect of Vinod's proposal was > > still under a bit of discussion; Chris Douglas though we should cut a > > branch-3 for the first 3.0.0 beta, which aligns with my original > thinking. > > This point doesn't necessarily need to be resolved now though, since > again > > we're still doing alphas. > > > > What we should get consensus on is the goal of keeping trunk stable, and > > achieving that by doing more development on feature branches and being > > judicious about merges. My sense from the Hadoop 3 email thread (and the > > more recent one on the async API) is that people are generally in favor > of > > this. > > > > We're just about ready to do the first 3.0.0 alpha, so would greatly > > appreciate everyone's timely response in this matter. > > > > Thanks, > > Andrew > > >
Re: [DISCUSS] Increased use of feature branches
Comparing with advantages, I believe the disadvantages of shipping any releases directly from trunk are more obvious and significant: - A lot of commits (incompatible, risky, uncompleted feature, etc.) have to wait to commit to trunk or put into a separated branch that could delay feature development progress as additional vote process get involved even the feature is simple and harmless. - These commits left in separated branches are isolated and get more chance to conflict each other, and more bugs could be involved due to conflicts and/or less eyes watching/bless on isolated branches. - More unnecessary arguments/debates will happen on if some commits should land on trunk or a separated branch, just like what we have recently. - Because branches will get increased massively, more community efforts will be spent on review & vote for branches merge that means less effort will be spent on other commits review given our review bandwidth is quite short so far. - For small feature with only 1 or 2 commits, that need three +1 from PMCs will increase the bar largely for contributors who just start to contribute on Hadoop features but no such sufficient support. Given these concerns, I am open to other options, like: proposed by Vinod or Chris, but rather than to release anything directly from trunk. - This point doesn't necessarily need to be resolved now though, since again we're still doing alphas. No. I think we have to settle down this first. Without a common agreed and transparent release process and branches in community, any release (alpha, beta) bits is only called a private release but not a official apache hadoop release (even alpha). Thanks, Junping From: Karthik Kambatla Sent: Friday, June 10, 2016 7:49 AM To: Andrew Wang Cc: common-...@hadoop.apache.org; hdfs-dev@hadoop.apache.org; mapreduce-...@hadoop.apache.org; yarn-...@hadoop.apache.org Subject: Re: [DISCUSS] Increased use of feature branches Thanks for restarting this thread Andrew. I really hope we can get this across to a VOTE so it is clear. I see a few advantages shipping from trunk: - The lack of need for one additional backport each time. - Feature rot in trunk Instead of creating branch-3, I recommend creating branch-3.x so we can continue doing 3.x releases off branch-3 even after we move trunk to 4.x (I said it :)) On Thu, Jun 9, 2016 at 11:12 PM, Andrew Wang wrote: > Hi all, > > On a separate thread, a question was raised about 3.x branching and use of > feature branches going forward. > > We discussed this previously on the "Looking to a Hadoop 3 release" thread > that has spanned the years, with Vinod making this proposal (building on > ideas from others who also commented in the email thread): > > > http://mail-archives.apache.org/mod_mbox/hadoop-common-dev/201604.mbox/browser > > Pasting here for ease: > > On an unrelated note, offline I was pitching to a bunch of > contributors another idea to deal > with rotting trunk post 3.x: *Make 3.x releases off of trunk directly*. > > What this gains us is that > - Trunk is always nearly stable or nearly ready for releases > - We no longer have some code lying around in some branch (today’s > trunk) that is not releasable > because it gets mixed with other undesirable and incompatible changes. > - This needs to be coupled with more discipline on individual > features - medium to to large > features are always worked upon in branches and get merged into trunk > (and a nearing release!) > when they are ready > - All incompatible changes go into some sort of a trunk-incompat > branch and stay there till > we accumulate enough of those to warrant another major release. > > Regarding "trunk-incompat", since we're still in the alpha stage for 3.0.0, > there's no need for this branch yet. This aspect of Vinod's proposal was > still under a bit of discussion; Chris Douglas though we should cut a > branch-3 for the first 3.0.0 beta, which aligns with my original thinking. > This point doesn't necessarily need to be resolved now though, since again > we're still doing alphas. > > What we should get consensus on is the goal of keeping trunk stable, and > achieving that by doing more development on feature branches and being > judicious about merges. My sense from the Hadoop 3 email thread (and the > more recent one on the async API) is that people are generally in favor of > this. > > We're just about ready to do the first 3.0.0 alpha, so would greatly > appreciate everyone's timely response in this matter. > > Thanks, > Andrew > - To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org
Re: [DISCUSS] Increased use of feature branches
Thanks for restarting this thread Andrew. I really hope we can get this across to a VOTE so it is clear. I see a few advantages shipping from trunk: - The lack of need for one additional backport each time. - Feature rot in trunk Instead of creating branch-3, I recommend creating branch-3.x so we can continue doing 3.x releases off branch-3 even after we move trunk to 4.x (I said it :)) On Thu, Jun 9, 2016 at 11:12 PM, Andrew Wang wrote: > Hi all, > > On a separate thread, a question was raised about 3.x branching and use of > feature branches going forward. > > We discussed this previously on the "Looking to a Hadoop 3 release" thread > that has spanned the years, with Vinod making this proposal (building on > ideas from others who also commented in the email thread): > > > http://mail-archives.apache.org/mod_mbox/hadoop-common-dev/201604.mbox/browser > > Pasting here for ease: > > On an unrelated note, offline I was pitching to a bunch of > contributors another idea to deal > with rotting trunk post 3.x: *Make 3.x releases off of trunk directly*. > > What this gains us is that > - Trunk is always nearly stable or nearly ready for releases > - We no longer have some code lying around in some branch (today’s > trunk) that is not releasable > because it gets mixed with other undesirable and incompatible changes. > - This needs to be coupled with more discipline on individual > features - medium to to large > features are always worked upon in branches and get merged into trunk > (and a nearing release!) > when they are ready > - All incompatible changes go into some sort of a trunk-incompat > branch and stay there till > we accumulate enough of those to warrant another major release. > > Regarding "trunk-incompat", since we're still in the alpha stage for 3.0.0, > there's no need for this branch yet. This aspect of Vinod's proposal was > still under a bit of discussion; Chris Douglas though we should cut a > branch-3 for the first 3.0.0 beta, which aligns with my original thinking. > This point doesn't necessarily need to be resolved now though, since again > we're still doing alphas. > > What we should get consensus on is the goal of keeping trunk stable, and > achieving that by doing more development on feature branches and being > judicious about merges. My sense from the Hadoop 3 email thread (and the > more recent one on the async API) is that people are generally in favor of > this. > > We're just about ready to do the first 3.0.0 alpha, so would greatly > appreciate everyone's timely response in this matter. > > Thanks, > Andrew >
[DISCUSS] Increased use of feature branches
Hi all, On a separate thread, a question was raised about 3.x branching and use of feature branches going forward. We discussed this previously on the "Looking to a Hadoop 3 release" thread that has spanned the years, with Vinod making this proposal (building on ideas from others who also commented in the email thread): http://mail-archives.apache.org/mod_mbox/hadoop-common-dev/201604.mbox/browser Pasting here for ease: On an unrelated note, offline I was pitching to a bunch of contributors another idea to deal with rotting trunk post 3.x: *Make 3.x releases off of trunk directly*. What this gains us is that - Trunk is always nearly stable or nearly ready for releases - We no longer have some code lying around in some branch (today’s trunk) that is not releasable because it gets mixed with other undesirable and incompatible changes. - This needs to be coupled with more discipline on individual features - medium to to large features are always worked upon in branches and get merged into trunk (and a nearing release!) when they are ready - All incompatible changes go into some sort of a trunk-incompat branch and stay there till we accumulate enough of those to warrant another major release. Regarding "trunk-incompat", since we're still in the alpha stage for 3.0.0, there's no need for this branch yet. This aspect of Vinod's proposal was still under a bit of discussion; Chris Douglas though we should cut a branch-3 for the first 3.0.0 beta, which aligns with my original thinking. This point doesn't necessarily need to be resolved now though, since again we're still doing alphas. What we should get consensus on is the goal of keeping trunk stable, and achieving that by doing more development on feature branches and being judicious about merges. My sense from the Hadoop 3 email thread (and the more recent one on the async API) is that people are generally in favor of this. We're just about ready to do the first 3.0.0 alpha, so would greatly appreciate everyone's timely response in this matter. Thanks, Andrew
