Compatibility Requirements (Was Re: [jboss-dev] AS 5.1 and JBoss Messaging 2)

[Jason T. Greene]

Tim Fox wrote:
> Adrian Brock wrote:
>> On Tue, 2009-02-17 at 14:00 -0600, Jason T. Greene wrote:
>>  
>>> Tim Fox wrote:
>>>    
>>>> Jason T. Greene wrote:
>>>>      
>>>>> I really wish we could. Tim said theres pretty much no was JBM2 can 
>>>>> make Beta1, but it could make CR1. The question is, would it be 
>>>>> stable and TCK compliant enough that it doesn't end up delaying GA?
>>>>>         
>>>> No, JBM 2.0 is a major release and is not compatible with JBM 1.4. 
>>>> That's why we can't replace JBM 1.4 in a minor release since AS 
>>>> minor versions need to be compatible, and why it's being offered as 
>>>> a technology preview, not replacement for default JMS provider.
>>>>       
>>> Where did this rule come, and what level of compatibility are we 
>>> talking about? We do need EE API compatibility, and ideally all of 
>>> our public APIs should be BC (so that developers don't have to 
>>> rewrite their apps), but IMO we don't need wire protocol 
>>> compatibility. You already can't cluster 5.1 and 5.0 together.
>>>
>>> The insane levels of compatibility should be reserved for EAP, but 
>>> 5.1 is the source of an EAP major version, so it doesn't need it.
>>>
>>>     
>>
>> No. JMS is a client/server protocol not a server/server protocol.
>>   
> Ah, but the compatibility requirements go beyond JMS (that API has been 
> static for years as you know).
> 
> What we were told at the time was that for minor releases, EAP requires 
> compatibility for the JMS stuff, but also all the other stuff we add 
> beyond JMS (read messaging JMX interface for messaging in 1.x).
> 
> Now.... if EAP is going to consume AS community version in lock step 
> fashion, then it also will need the same compatibility requirements. Ouch!
>

See the still ongoing EAP compatibility discussion on core. The short 
answer is that it's not required between major versions (provided there 
is a migration guide). Therefore we can break it in 5.1, since it's the 
first EAP 5 release. Any future 5.x release though will have to be more 
careful.

-- 
Jason T. Greene
JBoss, a division of Red Hat