[hibernate-dev] Compatibility Considerations wiki

Thu Aug 28 02:30:18 EDT 2014

2014-08-28 0:52 GMT+02:00 Steve Ebersole <steve at hibernate.org>:

> You have to admit that moving everything (again in this singular example)
> from org.hibernate.persister to a whole package would be extremely
> disruptive to OGM, et al.  Yes?
>

Yes, it would be disruptive. As said though, I personally would not not be
that annoyed about a package re-organization as it something I can quite
easily adapt to. Changed semantics of an API/SPI which require me to
actually re-program large parts of my application/integration would be more
scary.

Generally I think users (or integrators) are understanding about
incompatible changes in a major release, if there is a significant value to
these changes and they are not done for the fun of it. So it really boils
down to your question below whether we deem an api/spi/internal structure
worth it or not.

> So yes, making these changes is allowable under the rules laid out.  But
> that does not mean we run out ad try to screw over integrations :)  We
> still strive to maintain compatibility for SPIs as well as APIs.
>

Ok, that's good. The "But that is in no way by design; it just means that
it worked by happenstance" from before had me scared a bit :)

>  I think the relative question here is whether breaking these into
> api/spi/internal package structure (for OSGi, intention documentation
> purposes) alone warrants completely breaking compatibility with all
> integrations.  I'd tend to vote no.
>

I understand and I'd tend to agree for SPIs.

My point was more about parts considered internal where I don't see why
they couldn't be moved, because backwards-compatibility shouldn't be
relevant there. To sum it up, I'd be concerned about using annotations
(rather than packages) for marking parts as internal due to the reasons
outlined before, whereas using annotations for marking parts as SPI may be
a good middle-ground.

On Wed, Aug 27, 2014 at 1:20 AM, Gunnar Morling <gunnar at hibernate.org>
> wrote:
>
>> 2014-08-27 7:15 GMT+02:00 Steve Ebersole <steve at hibernate.org>:
>>
>> They are an SPI.  I'd break many Hibernate projects and third-party
>>> integrations if I just moved them...
>>>
>>
>> Yes, it would break client code using these SPIs, but isn't such breakage
>> covered by the rules you laid out before? You even allowed for breaking SPI
>> changes between minor release families (from 4.3 to 4.4), so such a
>> re-organization should be acceptable for a major release such as 5?
>>
>> Or are you saying that there is a category of changes which is "too big"
>> and thus never can be done? As a library user I personally can say that I'd
>> be ok with this sort of changes in a major upgrade, in particular if its as
>> easy to adapt to as just importing (otherwise un-altered) types from other
>> packages.
>>
>> Btw. what are the rules/expectations for API changes in a major version
>> (5), are breaking changes allowed there? The document only seems to
>> describe changes within a release family ("API contracts should be
>> considered stable across all releases within a major version (3.x or 4.x,
>> etc)").
>>
>>>
>>> On Tue, Aug 26, 2014 at 1:34 AM, Gunnar Morling <gunnar at hibernate.org>
>>> wrote:
>>>
>>>> 2014-08-25 18:37 GMT+02:00 Steve Ebersole <steve at hibernate.org>:
>>>>
>>>> This is all certainly true.  I think specifically of things like
>>>>> persisters, which by "package break down" are currently considered API.
>>>>>
>>>>
>>>> That's a good example. You say based on their package they are
>>>> considered API, but is that what you actually want for these types? Or, if
>>>> these types actually should not be considered an API, why can't they be
>>>> moved?
>>>>
>>>> If it's about not wanting to break existing users, I'd say then either
>>>> a) these types actually *are* an API (why otherwise would we care about
>>>> backwards compatibility with clients) or b) I wouldn't care about the
>>>> breakage (in a major release such as 5) because clients should not have
>>>> used those actually internal parts to begin with. Maybe the fact that those
>>>> parts are internal was not communicated clearly enough, but a major release
>>>> seems like the right occasion to fix this then.
>>>>
>>>> Also, as far as OSGi, I would suggest not worrying about that so much
>>>>> (Gunnar).  Keep in mind that even today this OSGi manifest info is
>>>>> generated by build logic.  Changing that build logic to look at annotations
>>>>> rather that parsing .class file path is not that big of a deal imo.
>>>>>  Devil's-in-the-details of course, but in theory it should not be a big
>>>>> deal.
>>>>>
>>>>>
>>>>> On Mon, Aug 18, 2014 at 6:12 AM, Sanne Grinovero <sanne at hibernate.org>
>>>>> wrote:
>>>>>
>>>>>> I won't speak for Steve's reasons, but I agree with the granularity
>>>>>> problem.
>>>>>>
>>>>>> For example you might not want to refactor the code to promote an SPI
>>>>>> to API (or simply fix a mistake), or viceversa demote an API to SPI,
>>>>>> as you moving the packages around would break backwards compatibility.
>>>>>> Essentially this means you can only fix the packages in that short
>>>>>> time in which you're in Alpha/Beta phase for a new major release,
>>>>>> which is a short period in which usually the team has other
>>>>>> priorities.
>>>>>>
>>>>>> The best example is ORM itself in it's current shape: we all know that
>>>>>> some classes should be moved into SPI or Impl, but we can't touch
>>>>>> them.
>>>>>> If your goal is to publish a nice set of javadocs for users which has
>>>>>> API only, annotations would allow to do this.
>>>>>>
>>>>>> Sanne
>>>>>>
>>>>>>
>>>>>> On 18 August 2014 08:14, Gunnar Morling <gunnar at hibernate.org> wrote:
>>>>>> > Hi Steve,
>>>>>> >
>>>>>> > Thanks for writing up these rules. That's very valuable information
>>>>>> for
>>>>>> > users and us as well.
>>>>>> >
>>>>>> > Only two remarks on the following:
>>>>>> >
>>>>>> >> The use of package names for this is unfortunately not granular
>>>>>> enough
>>>>>> > oftentimes.
>>>>>> >> Ultimately I would envision a better solution (annotations?)
>>>>>> >
>>>>>> > In which cases is it not granular enough? Can such case not always
>>>>>> be
>>>>>> > circumvented by refactoring code into separate classes within
>>>>>> separate
>>>>>> > packages?
>>>>>> >
>>>>>> > I'm fearing issues with e.g. distinguishing between public
>>>>>> (API/SPI) vs.
>>>>>> > internal parts on a finer level than the package, as that's what
>>>>>> OSGi but
>>>>>> > also JBoss Modules rely on. We cannot fully leverage the ability of
>>>>>> these
>>>>>> > module systems to "hide" internal parts of a module in that case.
>>>>>> >
>>>>>> > Also I think annotations are easier to "miss" than package names
>>>>>> when
>>>>>> > importing classes into an application, thus I'm concerned about
>>>>>> accidental
>>>>>> > referencing internal classes.
>>>>>> >
>>>>>> >> SPI contracts should be considered stable within a release family,
>>>>>> not
>>>>>> > necessarily across different release families.
>>>>>> >
>>>>>> > A specific example, similar to the API section, would be nice,
>>>>>> e.g.: "If
>>>>>> > you implement an application against an integration point from
>>>>>> Hibernate
>>>>>> > ORM 4.3.0, the expectation is that it works without changes when
>>>>>> updating
>>>>>> > to ORM 4.3.1. It should also continue to work when updating to ORM
>>>>>> 4.4.x in
>>>>>> > the very most cases, but that's not guaranteed."
>>>>>> >
>>>>>> > --Gunnar
>>>>>> >
>>>>>> >
>>>>>> > 2014-08-09 16:55 GMT+02:00 Steve Ebersole <steve at hibernate.org>:
>>>>>> >
>>>>>> >> There was a discussion in regards to our view on backwards
>>>>>> compatibility in
>>>>>> >> reference to HHH-9316.  I realized that we talk about this amongst
>>>>>> >> ourselves, but that I have never written these down.  So I did
>>>>>> that:
>>>>>> >>
>>>>>> >>
>>>>>> >>
>>>>>> https://github.com/hibernate/hibernate-orm/wiki/Compatibility-Considerations
>>>>>> >>
>>>>>> >> This is a first draft.  Let me know what you think.
>>>>>> >> _______________________________________________
>>>>>> >> hibernate-dev mailing list
>>>>>> >> hibernate-dev at lists.jboss.org
>>>>>> >> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>>>>>> >>
>>>>>> > _______________________________________________
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>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>