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. So do we want to keep our deprecated APIs forever with a special vote each time we really need to remove something from legacy? 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
