On Mar 29, 2012, at 9:29 PM, Caleb James DeLisle wrote: > > > On 03/29/2012 04:06 AM, Vincent Massol wrote: >> Transforming this thread in a brainstorming since we couldn't get to an >> agreement quickly. Once it's settled I'll launch a second vote. >> >> See below. >> >> On Mar 29, 2012, at 8:20 AM, Vincent Massol wrote: >> >>> Hi Caleb, >>> >>> On Mar 28, 2012, at 11:28 PM, Caleb James DeLisle wrote: >>> >>>> >>>> >>>> On 03/28/2012 02:03 PM, Vincent Massol wrote: >>>>> >>>>> On Mar 28, 2012, at 7:10 PM, Denis Gervalle wrote: >>>>> >>>>>> On Wed, Mar 28, 2012 at 12:27, Vincent Massol <[email protected]> wrote: >>>>>> >>>>>>> Hi devs, >>>>>>> >>>>>>> I'd like to change our deprecation strategy. Here's what we are >>>>>>> currently >>>>>>> supposed to use (we voted it a long time ago): >>>>>>> >>>>>>> http://dev.xwiki.org/xwiki/bin/view/Community/DevelopmentPractices#HDeprecation26LegacyStrategy >>>>>>> >>>>>>> " >>>>>>> In addition our rule is to keep @deprecated methods/classes for 2 final >>>>>>> releases after the version where they were first added has been >>>>>>> released as >>>>>>> final. >>>>>>> For example if a method is deprecated in, say XE 1.3M2 then the method >>>>>>> will be removed in 1.6M1 or after. Of course any major new release can >>>>>>> deprecate anything. For example a XWiki 2.0 release is allowed to break >>>>>>> backward compatibility (obviously we need to be careful to offer a >>>>>>> migration path for users of previous major versions). >>>>>>> " >>>>>>> >>>>>>> Issues: >>>>>>> * This seems a bit harsh to me for some of our users/devs in the >>>>>>> community. >>>>>>> * We're not following which proves to me it's not a good rule >>>>>>> * It doesn't say anything about Scripting APIs which require a greater >>>>>>> stability in order not to break all wiki pages >>>>>>> >>>>>>> Definition of a Scripting API: >>>>>>> * a Script Service (that's the new way of providing script apis) >>>>>>> * a class in the "api" package in xwiki-platform-oldcore (this is the >>>>>>> old >>>>>>> way of providing script apis) >>>>>>> >>>>>>> Thus I'd like to propose this new rule: >>>>>>> >>>>>>> * Deprecated methods can only be removed in the next Release Cycle. For >>>>>>> example something deprecated in version N.x can be removed in version >>>>>>> N+1.y >>>>>>> where x and y can be anything. This is logical since N+1 means a new >>>>>>> major >>>>>>> release and it's common to understand that major releases have no >>>>>>> guarantee >>>>>>> of API compatibility (See >>>>>>> http://en.wikipedia.org/wiki/Software_versioningfor example). >>>>>>> * For scripting APIs we can remove deprecated API only after 4 Release >>>>>>> Cycles. For example since we're in 4.x this means we >>>>>> >>>>>> >>>>>> Why four ? isn't it too much ? >>>>> >>>>> The reason I proposed 4 is because nowadays there still are quite a few >>>>> XWiki 1.x instances in the wild so if people have coded apps on 1.x and >>>>> then upgrade to 4.0 (for ex) it would be nice if their app still works. >>>>> However I think it's ok to not support apis done in 0.9. And next year it >>>>> would be ok to drop 1.x api support, etc. >>>>> >>>>> It's long but then we can see in the wild that it's important we provide >>>>> stable scripting apis for users since they're used a lot while java apis >>>>> are used by more savvy user (developers) and thus having a shorter >>>>> removing cycle for them (1 year) should be ok. >>>>> >>>>> What would you like to propose instead? >>>> >>>> I'd rather we had no hard rules lest dogmatic adherence to the rules >>>> becomes an excuse not to fulfill our obligation to do what's best for the >>>> software. >>>> I'm not exactly sure what `break' means since there's no reason I can see >>>> for these functions to be removed from the compatibility aspect. >>> >>> The reason for having a well-defined rule is: >>> >>> * I think it's better than having to send a vote every time we want to >>> remove a deprecated api. It certainly is much simpler. >>> * Publicly document it so that our users will know about this rule and >>> adapt their deprecation replacement strategy as a consequence >>> >>> I really think we ought to publish our deprecation and removal policy. >>> >>>> I propose: >>>> >>>> #1 Move remaining deprecated scripting API methods from oldcore into >>>> legacy-oldcore compatibility aspect. >>>> That means these: >>>> http://nexus.xwiki.org/nexus/service/local/repositories/releases/archive/org/xwiki/platform/xwiki-platform-oldcore/4.0-milestone-1/xwiki-platform-oldcore-4.0-milestone-1-javadoc.jar/!/index.html >>> >>> This is *already* our strategy, see the "2-step" strategy defined here: >>> http://dev.xwiki.org/xwiki/bin/view/Community/DevelopmentPractices#HDeprecation26LegacyStrategy >>> >>> Everyone is already supposed to do this and do this regularly. The issue is >>> that before being able to move a lot of code we need to fix a lot of >>> deprecation usages. >>> >>> <OT>It could be nice to organize a "deprecation day" where we try to squash >>> as many deprecation usages as possible</OT> >>> >>>> #2 Get xwiki-enterprise building and testing with xwiki-platform-oldcore >>>> instead of xwiki-platform-legacy-oldcore. >>>> Add an xwiki-enterprise-legacy-jetty-hsql build profile so that we can >>>> test in parallel, with and without legacy-oldcore. >>>> I ran the UI tests and it appears that we have a few dependencies on >>>> legacy-oldcore. IMO this is very bad. >>> >>> This is very very bad and goes against our current policy indeed. >>> >>>> However it doesn't look like we have too many. >>>> Lets get it running, see the failing tests, report the issues, then fix >>>> them. >>> >>> This is a very good idea and I'm all for it. >>> >>>> #3 Stop shipping legacy-oldcore by default. Users can always swap >>>> platform-oldcore for it on their own. >>> >>> It's not just oldcore, we have several legacy modules and theoretically we >>> can have as many as we have modules. >>> >>> I don't think we cans stop shipping a distribution with legacy modules but >>> what would be nice is to start shipping a distribution without legacy >>> modules. We could even highlight this one as first listed to raise >>> awareness. >>> >>>> #4 Aggressively move deprecated internal (non-script api) code into the >>>> compatibility aspect, this will allow us to simplify the oldcore, and >>>> potentially even remove dependencies. >>> >>> This is already our strategy. Again for some cases it's hard but I'm all >>> for it. A lot of us introduce new APIs but don't update the code to use the >>> new API creating a lot of deprecation usages suddenly. I'm all for this >>> too. >>> >>>> If we want to stall, we can stall at #3, having 1, 2, and some of 4 taken >>>> care of will make the final decision the flip of a switch. >>> >>> This is all great but it doesn't solve the VOTE. It's a different topic and >>> something we've already VOTED and doing. I agree it would be nice to do it >>> more aggressively but it's very different from the deprecation policy I'd >>> like to find an agreement on. >>> >>> Unless I misunderstood you and your proposal is to NEVER remove deprecated >>> APIs, which is a solution of course. I'm a bit afraid of the consequences. >> >> Actually this is not a bad idea. I've thought about it and couldn't find a >> real blocker to this strategy of never removing deprecated APIs. Some >> thoughts though: >> >> * When we remove a class to replace it with another one we need to invent a >> mechanism in the main code to allow pluggability. Sometimes this is nice to >> have but sometimes it's a bit contrived and it would be nice to remove this >> pluggability when it's no longer needed. Not that bad though. >> * We currently have no way to know if something in legacy is working since >> we're not using it anymore :) The only solution I could think of would be to >> add some functional tests to prove that these old apis still work. > > Writing additional tests for deprecated code means we are basically > maintaining it, I think this is the wrong direction, not to mention feasibly. > I suggested running the normal tests twice just to make sure legacy has not > broken something which we do use. > >> >> So do we want to keep our deprecated APIs forever with a special vote each >> time we really need to remove something from legacy? > > This only would make any sense in the context of legacy as a method graveyard > which was not shipped and only provided to users hoping to fix their broken > apps. > That said, unused unmaintained code in an evolving codebase is just as bad if > not worse than nonexistant code so +1 to removing things from legacy. > > WDYT of deprecating in place for a small span of time, then moving to -legacy > for a larger span of time and finally removing from legacy.
AFAIK this is exactly the current strategy :) What's different from what's already written on http://dev.xwiki.org/xwiki/bin/view/Community/DevelopmentPractices#HDeprecation26LegacyStrategy ? Thanks -Vincent > This paired with not shipping -legacy by default would give users a stepping > stone between "works" and "broken". > > Caleb > >> >> Thanks >> -Vincent >> >>> BTW I'd like to update our current strategy documentation to a 3-step >>> strategy: >>> * Step 1: deprecate >>> * Step 2: move to legacy modules (this means removing our usages of the >>> deprecated apis) >>> * Step 3: remove from legacy modules <-- This is what we're voting on here >>> >>> i.e. we could do step3 only when we've done steps 1 and 2 first. This is a >>> good strategy IMO because it means that we would have done step2 which is >>> required to be able to remove a deprecated api anyway… ;) >>> >>> Thanks >>> -Vincent >>> >>>> Caleb >>>> >>>> >>>> >>>>> >>>>> Thanks >>>>> -Vincent >>>>> >>>>>>> can remove deprecated APIs from 0.x releases. And when we start 5.x we >>>>>>> will be able to remove deprecated scripting apis deprecated in 1.x. >>>>>>> >>>>>>> Here's my +1 >>>>>>> >>>>>>> Thanks >>>>>>> -Vincent _______________________________________________ devs mailing list [email protected] http://lists.xwiki.org/mailman/listinfo/devs
