Hi Vincent, On Wed, Feb 12, 2014 at 10:34 AM, [email protected] <[email protected]>wrote:
> Hi Denis, > > > On 12 Feb 2014 at 02:34:13, Denis Gervalle ([email protected](mailto: > [email protected])) wrote: > > > Hi Vincent, > > > > I have the exact same reading then Thomas. The @since tag should not be > use > > for anything else than what it is made for: notifying the user of any > > package/class/method at which point it has been introduced. A > > package/class/method is define by its canonical name, and any change in > it > > is therefore another package/class/method, even if it has the exact same > > signature. > > > > While I understand that this could have not been properly followed in the > > past, this is clearly a mistake, and it is mostly due to the lack of > > automation/check on these annotations. > > Ok, let’s put this part behind us since we agree :) I’m going to add the > following to our dev practices document, let me know if you guys are ok: > > ------ > = @Since tag practices = > > We follow the practices defined in the [[official JavaDoc guide>> > http://www.oracle.com/technetwork/java/javase/documentation/index-137868.html#@since] > ]. > > Specifically, the @since tag should be used in cases both when a new type > is introduced (class, interface, enum, method, public class field, etc) and > when a type is moved/renamed. > > Also note that when a type is moved to another package if it already had a > @since tag, it’s required to update it with the new version since the FQN > has changed. > > The preferred format for common @since messages are listed below. > > |=Reason|=@since Description > |Renamed a former method that’s been deprecated|@since <version>, rename > of {@link #someMethod()} > |Renamed a former type that’s not been deprecated (young API)|@since > <version>, rename of {@code <old FQN of type>} > |Generalization of method|@since <version>, replaced {@link #someMethod()} > |New type|@since <version> > ------ > > (inspired from > http://www.liferay.com/community/wiki/-/wiki/Main/Javadoc+Guidelines#section-Javadoc+Guidelines-@since+tags+for+methods > ). > +1 > > The removal of the @Unstable annotation has nothing to do with @since, > and > > should not be mixed up. > > > > I found very annoying to see the need to know for sure the introduction > > time of the @Unstable annotation, simple to respect a rules we have only > > voted to avoid those @Unstable to be left for ever. Normally, the "owner" > > of the newly introduced API, should take care to remove those @Unstable > as > > earlier as possible, and the maximum should only be reach in very rare > > cases. So, my feeling is that those rare case could be solved using Git > > history/blame if ever needed. > > Why do you say it’s rare? I have not said it is rare, but that it should be rare ! > Nobody remembers to remove @unstable, me being the first. I need a > reminder of some sort. And even if it was me removing them without a > reminder, I'd still need to remember when I introduced a new API... > You should follow the rules we defined for @Unstable, else it is useless to vote them: "However, the previous rule [ed: removal after a maximum of 1 full] is only a maximum and developers are encouraged to remove the unstable annotation whenever they feel that the API should come out of unstability. When this happens the standard deprecation mechanism then kicks in." This is an important rule. If we forgot about the @Unstable we have introduced, it means we do not use it right. Keeping stuff that we do not work on in an unstable state is useless, and does not help our users. If we forgot what you are working on, I am worried. > > > So I am not in favor of any of your "new" options. I would simply clarify > > the rules for @since (if really needed for those not understanding the > > obvious). I also remind all committers that it is your responsibility to > > remove the @Unstable you have introduce in due time. > > This is just wishful thinking and will never happen. We need some process > to ensure this either automated or manual. > > It’s like saying that it’s everyone’s responsibility to document the new > features he introduces in the release notes and on xwiki.org. Do you > think this worked by itself and that all devs did it by themselves? It > didn’t happen for 5 years and it wouldn’t have for the following 10 years > if we hadn’t set up a reminder. And the reminder is that when we release we > check jira for undocumented issues. This 1 year cycle reminder for > @unstable is exactly the same. If we knew how to automate it quickly we > would do it, except that we don’t so we have to set up a reminder. > While I understand your point, I am still really annoyed by this way of thinking. @Unstable should only be used when you introduce new stuffs, and until you remove it, it is almost like you have not really add it for our users. It looks like unfinished work, that should still have at least a corresponding issue open. Announcing new @Unstable API in the RN is closing one issue, but opening another one which will lead to announce the same new API as stable at some later point. If you cannot open that second issue, why do you keep the API @Unstable, what do you fear (except the SPI aspect, see below) ? > Note that I did all the work of checking and you’re still complaining :) I > find that pretty unfair! Note that I raised the parts of the code where > @unstable had to be removed and ATM I’m still the only one to have removed > those tags but that’s probably because devs are still busy on 5.4.x and > didn’t get the time to look at 6.0. > Where did you see me complaining ? I have just said that what you had need to do should not have been in first place, except in rare cases. > > If you really want to add new annotations, I would be far more > interested > > to distinguish API and SPI, and provide them a different stability, > > allowing us more flexibility :) > > 1) Even if we were distinguishing API and SPI we would still need to be > able to remove @unstable tags at least for the API part so it doesn’t > change anything to the current discussion. > Not exactly, it would be easier to remove early the @Unstable annotation on API interfaces. Stabilizing an SPI is a bigger commitment, and require more time. > > 2) We started discussing API and SPI on the list and the main issue is > that xwiki is a dev platform and it’s hard to make a difference between an > API and a SPI. The only one that makes sense to me is a difference between > a Scripting API from a Java API (instead of API vs SPI) and I’d be willing > to define different rules for both. But we even discussed that and said we > wanted XWiki to be a dev platform and not just an Application, and if you > consider it like a dev platform then you need stable APIs for everything > (same as with a dev language, imagine Java breaking stuff in each release, > do you think it would have been successful?). In Java Platform, there are some distinctions between API and SPI as well, simply look at the spi packages, the Spi suffixed interface name, .... > If we want to encourage people to develop against our Java API we need > some stability. An API could be stable and be improved by adding new methods and deprecating older one, while an SPI cannot and require a separate additional interface, this is what I am talking about. > Now we could also say that we don’t want that anymore and that not a lot > of people are coding against our Java API and thus it doesn’t matter at > this stage if we break them since there are only a few affected persons. > I’d be ok with that provided we preserve the scripting APIs. We would need > to handle the Scripting API requiring PR though and decide if it’s ok to > break them. It would have to be ok as otherwise you can access the full > XWiki Java API from those… This means we would break a certain amount of > extensions since quite a few do use protected scripting API as they need it > and don’t have equivalent safe APIs. I do not see it that way. Declaring our interface as an API or an SPI would be more a declaration of our intent and our commitment. It is like when we put public stuff in an internal package, you may still use it externally, but you know the risks. Distinguishing would only help users implementing an interface, not users simply using it. For an interface declared API (the default, no annotation required), we declare that we may freely add new methods, when an interface is declared SPI, it is guaranteed to be left unchanged definitely. This does not prevent you to implement an API, but you know the risks. The benefit for us would be an increased flexibility when we evolved an API. It would reduced the need for a complete replacement, allowing a more smooth evolution of our API. Choosing is fairly simple for me. By default, all interfaces are API. Only a few of our existing public interface will be declared SPI, and we will ensure those will be frozen definitively. Which one ? The one we have precisely design to be also implemented by a user. Once again, it does not prevent a user to implement an API, but he will know that it should be prepare to a possible breakage. Let me take a very simple concrete example in my domain, the security authentication module. The AuthorizationManager interface is an API, we do not expect users to implement it differently most of the time. But the AuthorizationSettler interface has been designed for and will be an SPI. Users are encouraged to implement their own AuthorizationSettler if they want to customize the behavior of the AuthorizationManager. Even more typical, the RightDescription interface is only an SPI, since we never implement it. > Generally speaking, I’m fine with setting up a different process for > handling young apis but you have to propose something that can work. Just > proposing something that is sure to fail will not help, it’ll just push > stuff under the rug. > Introducing more flexibility in our backward compatibility promises is IMO a way to reduce as much as possible the length of time we keep the @Unstable annotation. Reducing the usage of @Unstable is beneficial to our users, and also to us. > > Now, are you willing to spend time writing an automated check when > @Unstable need to be removed? It can be done for sure, it could be > something like this: > - use checkstyle’s java code parser and write a checkstyle rule to find > all @unstable tags in javadoc (easy difficulty) > - for each @unstable found, use Git to find out when it was introduced. > There are some potential issues with this since the code needs to be > careful to follow renames for example (medium difficulty) > - then map the date with the XWiki version (hard difficulty since you need > to maintain a map or query xwiki.org, or easy difficulty if we use > @Unstable(“5.4M1”) since we have the XWiki version in the tag itself and > the previous step isn’t needed anymore and only the following step is > required) > - extract the current version from the pom.xml and report an error if > @unstable has to be removed > If we have the above need, I prefer we simply stop using the @Unstable annotation. It became counter productive for our users. If you have time for such automation, use it to automate the @since to make it more accurate, which will be far more helpful to us and our users. Thanks, > > Thanks > -Vincent > > > Thanks, > > > > > > > > On Tue, Feb 11, 2014 at 3:22 PM, Thomas Mortagne > > wrote: > > > > > On Tue, Feb 11, 2014 at 3:19 PM, Thomas Mortagne > > > wrote: > > > > On Tue, Feb 11, 2014 at 3:15 PM, [email protected] > > > wrote: > > > >> > > > >> See below. > > > >> > > > >> On 11 Feb 2014 at 13:17:03, Marius Dumitru Florea ( > > > [email protected](mailto:[email protected])) > > > wrote: > > > >> > > > >>> I agree with Thomas and Denis, but I must admit that I haven't > updated > > > >>> the @since version when I did refactorings in the past. I'll pay > > > >>> attention to this next time. > > > >>> > > > >>> Thanks, > > > >>> Marius > > > >>> > > > >>> On Mon, Feb 10, 2014 at 2:51 PM, Denis Gervalle wrote: > > > >>> > On Sun, Feb 9, 2014 at 11:16 PM, Thomas Mortagne > > > >>> > wrote: > > > >>> > > > > >>> >> On Sun, Feb 9, 2014 at 6:10 PM, [email protected] > > > >>> >> wrote: > > > >>> >> > Hi devs, > > > >>> >> > > > > >>> >> > I always ask myself this question so I think we need a common > > > agreement. > > > >>> >> > > > > >>> >> > So here's the question: > > > >>> >> > * I have added some code in version N and this I have a > "@since > > > N" in > > > >>> >> the code > > > >>> >> > * In version M (M > N), I move the class/interface to a new > > > package > > > >>> >> > > > > >>> >> > Question: Do I change the @since annotation to "@since M" or > not? > > > >>> >> > > > > >>> >> > 2 possibilities: > > > >>> >> > * Reasoning 1: it's a new class/interface since the FQN of the > > > >>> >> class/interface has changed and thus we should use "@since M" > > > >>> >> > * Reasoning 2: even though the FQN has changed it's still the > > > same code > > > >>> >> that was moved and from a user POV, it was still introduced in > > > version N > > > >>> >> and thus we should keep "@since N" > > > >>> >> > > > > >>> >> > WDYT? > > > >>> >> > > > > >>> >> > I'm hesitating. The most technically correct answer is > Reasoning > > > 1 IMO > > > >>> >> but the most useful one is probably Reasoning 2 since the > question > > > we wish > > > >>> >> to answer is probably: "when was this code first introduced?". > > > >>> >> > > > > >>> >> > Thus reasoning 2 seems slightly better to me. > > > >>> >> > > > >>> >> Big -1 for 2 which is totally out of context, @since indicate > that > > > you > > > >>> >> can use that class or method since that version in you code and > > > >>> >> indicate you which version you are going to be compatible with. > If > > > you > > > >>> >> change the class or method your can't keep the same @since. If > you > > > >>> >> want to know since when the feature exist look at xwiki.org... > > > >>> >> > > > >>> > > > > >>> > I completely agree with Thomas, a -1 for 2) > > > >>> > I would add that if you want to know from where the code come > from, > > > Git is > > > >>> > your best friend. > > > >> > > > >> > > > >> > > > >> I don't fully agree with this. > > > >> > > > >> The point of the @since tag is exactly to NOT have to check in Git > to > > > see when some code was introduced! And with your logic, the @since tag > is > > > never needed at all since we can always check in Git, and it's as easy > to > > > check in Git for Reasoning 1 than it is for Reasoning 2. > > > > > > > > The point of @since is to indicate since when a signature exist which > > > > means that 2 is completely wrong. I never talked about git, I don't > > > > care how you know since when a feature exist but please don't use > > > > @since which has a different meaning for that. > > > > > > > >> > > > >> If you start changing the @since then it makes it impossible to > > > properly remove the @Unstable annotations later on since for each > @Unstable > > > annotation you'll need to do some deep Git archeology to reconstruct > the > > > first time the API was introduced. > > > >> > > > >> Also, I can tell you that a lot of devs (the majority, if not 80%) > have > > > been doing Reasoning 2 since the beginning of our usage of @since, > since > > > it's the simplest thing to do and it's what you get by default if you > don't > > > do anything... I know I did it, I know Marius did too and I'm pretty > sure > > > others too. > > > >> > > > >> So to recap, my points are: > > > >> * If you need to find out when some class was moved in another > package > > > you can always check Git and you don't need the @since that for this > > > >> * Reasoning 1 makes it almost impossible in practice to remove > > > @Unstable annotations > > > >> * Reasoning 2 is complex to implement (the proof being that for > most of > > > our code it wasn't done) > > > >> > > > >> > > > >> > > > >> Note that this discussion is important since we never formalized > how to > > > use the @since annotation (it's not documented on > > > http://dev.xwiki.org/xwiki/bin/view/Community/DevelopmentPractices). > > > >> > > > >> Also note that > > > > http://www.oracle.com/technetwork/java/javase/documentation/index-137868.html#@sincedoesn'texplain > what to do when a class/interface is moved elsewhere. I > > > googled and couldn't find how other projects handle the since tag. > > > > > > It does no say it because it's obvious, if you change the package you > > > change the name, the class short name does not have any value in Java. > > > > > > >> > > > >> So taking everything into account we have the following options: > > > >> > > > >> A) Update the @since value when we move a class/interface to another > > > package. But force the @Unstable annotation to have a text specified > (ATM > > > it's optional) with the rule of specifying when the API is introduced. > For > > > example @Unstable("Introduced in 5.4M1"). > > > >> > > > >> B) Keep what we've been doing implicitly, which is to not change the > > > @since value when a class/interface is moved to another package and > > > consider that this @since tag corresponds to when the code was first > > > introduced independently of its class/interface location. In this case > no > > > need to use a text for the @Unstable annotation. > > > >> > > > >> C) Use some other annotation like for example @Introduced("5.2") or > > > @Introduced in 5.2 (javadoc). > > > >> > > > >> As for automating the addition of the since tags, I couldn't find > > > anything good for us to use. FTR I found: > > > >> - > > > > http://stackoverflow.com/questions/3417243/automatic-since-javadoc-tag-for-releasesbutthe > maven plugin doesn't do magic. > > > >> - > > > > http://help.eclipse.org/indigo/index.jsp?topic=%2Forg.eclipse.pde.doc.user%2Freference%2Fapi-tooling%2Fapi_since_tags.htm > > > >> > > > >> While I prefer A) which I find more technically correct I think it's > > > also a lot more work to enforce (in lots of places it means duplicating > > > information between @since and @unstable) so I'm hesitating, especially > > > since we've been doing B implicitly. > > > >> > > > >> Any idea/preference? > > > >> > > > >> Thanks > > > >> -Vincent > > > >> > > > >> > > > >>> > I take the occasion to also mention that it would be nice to > have a > > > better > > > >>> > way to maintain those @since. At least a check of presence, or > even > > > better > > > >>> > a check of correctness, in the build would nice to have. The must > > > being to > > > >>> > have those @since added automagically :) > > > >>> > > > > >>> > > > > >>> >> > > > >>> >> > > > > >>> >> > Thanks > > > >>> >> > -Vincent > > _______________________________________________ > devs mailing list > [email protected] > http://lists.xwiki.org/mailman/listinfo/devs > -- Denis Gervalle SOFTEC sa - CEO _______________________________________________ devs mailing list [email protected] http://lists.xwiki.org/mailman/listinfo/devs
