Hi all, +1 for enforcing "a" codestyle using "a" tool.
As the project grows both in terms of LOCs and contributors, this becomes more and more important as it eliminates some potential points of friction without any additional effort. >From the discussion, I am leaning towards having a single commit with all the codestyle-related changes. This will avoid sprinkling refactoring commits all over the place for the next year or more. But if this is the price to pay for having consensus on a tool, then I am ok with gradual implementation. I believe that the value added by having an automated process of enforcing a codestyle exceeds the cost of the nuisance of gradual refactoring. As for the actual format, I like the google-java-format but again, if the community agrees on a different one I would not oppose that (as long as it does not use the same amount of indentation for method args and method body :P). Cheers, Kostas On Wed, Oct 7, 2020 at 10:26 AM Chesnay Schepler <ches...@apache.org> wrote: > > To me, ratchet seems to combine the worst aspects of both approaches. > You get disruptive changes, but only in singular files, > for something mundane as a typo fix or import change, which would be > annoying to keep separate from the actual functional changes in a PR. > > On 10/7/2020 10:04 AM, Matthias Pohl wrote: > > I find the ratchet feature you're suggesting interesting. But Arvid has a > > point referring to the blog post about ignoring revisions in git blame [1]. > > Adding the configuration file for commits to ignore revs as proposed in the > > blog post makes it even easier. One problem I see is that this is not > > supported by Github (yet?) [2] as mentioned in [1]. > > > > Considering all that I prefer applying the code style in one go. I have no > > strong opinion on what codestyle is the best. > > > > PS: We used spotless in the project I previously worked on. It was > > convenient to use. > > > > [1] > > https://www.moxio.com/blog/43/ignoring-bulk-change-commits-with-git-blame > > [2] > > https://github.community/t/support-ignore-revs-file-in-githubs-blame-view/3256 > > > > On Tue, Oct 6, 2020 at 6:00 PM Aljoscha Krettek <aljos...@apache.org> wrote: > > > >> Maybe I wasn't very clear on how the ratchet works. The changes are > >> gradual yes, but it doesn't leave you an option: if you touch a file you > >> will it will have to conform to the coding style afterwards. It's not > >> like the previous gradual process we had before where it would be based > >> on people actively working towards a style. > >> > >> That being said, I also completely like the option of just doing one big > >> change commit. > >> > >> Regarding actual coding styles: we're a bit limited by what tools exist. > >> I like Spotless because it can be used to both check and apply a style. > >> Then you need a formatter that works with Spotless and of those we only > >> have the Eclipse Formatter, google-java-format, and Prettier. Prettier > >> is a Javascript tool that I would like to avoid. Eclipse is doable but > >> you need to fiddle with configuration files. I like google-java-format > >> because of it's take-it-or-leave-it approach. You either use the style > >> or you don't but it's very thorough. The downside is that it won't do > >> tabs-only formatting. > >> > >> Best, > >> Aljoscha > >> > >> On 06.10.20 17:43, Arvid Heise wrote: > >>> After having written that I did a quick search, you can even use git > >> blame > >>> with one big massive change commit [1], which would further help the idea > >>> of "just get over with it". > >>> > >>> With that option, I'd even change all whitespaces if the community thinks > >>> that it's a better option (a separate discussion that I'll gladly skip). > >>> > >>> [1] > >>> > >> https://www.moxio.com/blog/43/ignoring-bulk-change-commits-with-git-blame > >>> On Tue, Oct 6, 2020 at 5:38 PM Arvid Heise <ar...@ververica.com> wrote: > >>> > >>>> I'm also +1 for automatically enforceable code style. > >>>> > >>>> I also would just go over it as Chesnay said. While it makes some > >> changes > >>>> a bit harder to track (inline git blame), it's easy to skip over in any > >> git > >>>> history and if it's only one massive commit, then it's also much easier > >> to > >>>> ignore than many gradual changes. Further, if we just do it once, git > >> blame > >>>> will quickly become more reliable again. > >>>> > >>>> Btw I completely don't care about the code style as long as it plays > >> well > >>>> with IntelliJ (it used to be different, but things change :p). > >>>> > >>>> On Tue, Oct 6, 2020 at 5:23 PM Chesnay Schepler <ches...@apache.org> > >>>> wrote: > >>>> > >>>>> We shouldn't switch to spaces _now_; cutting this bit from your > >> proposal > >>>>> will massively simplify things and there's hardly any value in changing > >>>>> it. > >>>>> > >>>>> Also I'm getting rather tired of this constant idea of "gradual > >>>>> application". We've been doing this for 2-3 years now since we > >>>>> introduced Checkstyle and basically got nowhere. We should just bite > >> the > >>>>> bullet and get it over with; we could've solved this whole problem > >>>>> already. > >>>>> > >>>>> In conclusion, I'm +1 on finally locking down the codestyle and > >> applying > >>>>> it immediately, I'm -1 on any gradual application scheme because they > >>>>> _just don't work_. > >>>>> > >>>>> On 10/6/2020 2:15 PM, Aljoscha Krettek wrote: > >>>>>> Hi All, > >>>>>> > >>>>>> I know I know, but please keep reading because I recently learned > >>>>>> about some new developments in the area of coding-style automation. > >>>>>> > >>>>>> The tool I would propose we use is Spotless > >>>>>> (https://github.com/diffplug/spotless). This doesn't come with a > >>>>>> formatter but allows using other popular formatters such as > >>>>>> google-java-format. The nice thing about Spotless is that it serves as > >>>>>> a verifier for CI but can also apply the configured style > >>>>>> automatically. That is, for the programmer all she has to do is `mvn > >>>>>> spotless:apply` to fix any style violations. > >>>>>> > >>>>>> An interesting feature, which was (somewhat) recently added is > >>>>>> "ratchet" > >>>>>> ( > >> https://github.com/diffplug/spotless/blob/main/plugin-maven/README.md#ratchet > >> ). > >>>>>> With this, you can set up Spotless to only apply it's rules to files > >>>>>> that were changed after a configured commit. This would allow a > >>>>>> gradual application of the new coding style instead of one big change. > >>>>>> > >>>>>> If we decide to use Spotless, we would of course also have to decide > >>>>>> on a coding style. For this I would propose google-java-format, which > >>>>>> the flink-statefun project uses. The main difference from our current > >>>>>> "style" is that this uses spaces instead of tabs for indentation. By > >>>>>> default it would be 2 spaces but it can be configured to use 4 spaces > >>>>>> which would make code look more or less like our current style. There > >>>>>> are no more configuration knobs, so using tabs is not an option. > >>>>>> > >>>>>> Finally, why should we do this? I think most engineers agree that > >>>>>> having a common enforced style is good to have so I only want to > >>>>>> highlight a few thoughts here about things we could improve: > >>>>>> > >>>>>> - No more nits about coding style in reviews, this makes it easier > >>>>>> for both the reviewer and developer > >>>>>> > >>>>>> - No manual fixing of Checkstyle errors because Spotless can do that > >>>>>> automatically > >>>>>> > >>>>>> - Because Flink is such a big project little islands of coding style > >>>>>> have formed between people that commonly work on components. It can be > >>>>>> a nuisance when you work on a different component and then reviewers > >>>>>> don't like your typical coding style. And you first have to get used > >>>>>> to the slight differences in style when reading code. > >>>>>> > >>>>>> There are also downsides I see in this: > >>>>>> > >>>>>> - We break the history, but both "git blame" and modern IntelliJ can > >>>>>> ignore whitespace when attributing changes. So for files that are > >>>>>> already "well" formatted not much would change. > >>>>>> > >>>>>> - In the short-term it will be harder to apply changes both to > >> master > >>>>>> and one of the release-x branches because formatting will be > >>>>>> different. I think this is not too hard though because Spotless can > >>>>>> automatically apply the style. > >>>>>> > >>>>>> In summary, we would have some short-term pain with this but I think > >>>>>> it would be good in the long run. What are your thoughts? > >>>>>> > >>>>>> Best, > >>>>>> Aljoscha > >>>>>> > >>>>> > >>>> -- > >>>> > >>>> Arvid Heise | Senior Java Developer > >>>> > >>>> <https://www.ververica.com/> > >>>> > >>>> Follow us @VervericaData > >>>> > >>>> -- > >>>> > >>>> Join Flink Forward <https://flink-forward.org/> - The Apache Flink > >>>> Conference > >>>> > >>>> Stream Processing | Event Driven | Real Time > >>>> > >>>> -- > >>>> > >>>> Ververica GmbH | Invalidenstrasse 115, 10115 Berlin, Germany > >>>> > >>>> -- > >>>> Ververica GmbH > >>>> Registered at Amtsgericht Charlottenburg: HRB 158244 B > >>>> Managing Directors: Timothy Alexander Steinert, Yip Park Tung Jason, Ji > >>>> (Toni) Cheng > >>>> > >>> >
