[hibernate-dev] Various expectation changes in hibernate-core after consolidating hibernate-entitymanager

[Vlad Mihalcea]

Hi,

I'll update the docs to match the changes.

Vlad

On Tue, May 3, 2016 at 6:18 AM, Steve Ebersole <steve at hibernate.org> wrote:

> Vlad, there is one last failure in those documentation
> tests: org.hibernate.userguide.flush.AutoFlushTest#testFlushAutoSQLNativeSession
>
> This is indicative of another change specifically consolidating Query.
>
> On Sat, Apr 30, 2016 at 9:06 AM Steve Ebersole <steve at hibernate.org>
> wrote:
>
>> We are seeing this too in your documentation tests.  So its ok to just
>> change those to wrap the writes/flushes in a transaction?  (they are not
>> now)
>>
>>
>> On Tue, Apr 26, 2016 at 10:09 AM Vlad Mihalcea <mihalcea.vlad at gmail.com>
>> wrote:
>>
>>> Hi,
>>>
>>> It's fine if we stick to the JPA spec so that only read ops are allowed
>>> to be executed outside of a transactional context. Most applications use
>>> either Java EE or Spring, so transaction boundaries are usually enforced
>>> anyway.
>>>
>>> It's also fine to throw an exception if the object being checked within
>>> the Persistence Context is not an entity. This might break some existing
>>> use cases, but we are covered by the JPA spec :D
>>>
>>> In the getTransaction() case, I still believe we should offer two
>>> strategies: a JPA and a native one, the choice being made based on the
>>> current bootstrap procedure or some configuration property.
>>>
>>> Vlad
>>>
>>> On Tue, Apr 26, 2016 at 5:53 PM, Steve Ebersole <steve at hibernate.org>
>>> wrote:
>>>
>>>> 2. "Another change in expectation is in regards to operations outside
>>>>> of a transaction" - in JPA we can execute queries outside a
>>>>> transaction, but any write will fail if there is no transactional context,
>>>>> which is reasonable for me too. If Hibernate allows writes outside of a
>>>>> transactional context, that's definitely a thing we should not support
>>>>> anyway.
>>>>>
>>>>
>>>> Well we'll agree to disagree about the validity of allowing queries
>>>> outside the scope of a transaction; it does not matter, because JPA says it
>>>> should be allowed, so we have to allow that.
>>>>
>>>> However, historically Hibernate allowed writes outside the scope of a
>>>> transaction as well (auto-commit support), so that is what I am talking
>>>> about.  After pulling over HEM logic we now have some test failures due to
>>>> tests trying to write data outside of an explicit transaction (
>>>> javax.persistence.TransactionRequiredException).
>>>>
>>>> So I propose we continue to expect that as a failure starting in 5.2.
>>>> For queries we will continue to supports it, but only because JPA requires
>>>> us to; not because it is a valid concept.
>>>>
>>>>
>>>>
>>>>> 3. "Asking a Session if is contains (Session/EntityManager#contains) a
>>>>>  non-entity" - we can handle this with the separate exception handler
>>>>> strategies to retain both JPA and Hibernate behaviors.
>>>>>
>>>>
>>>> Why?  This is exactly the kind of thing I have in mind when I talk
>>>> about the unnecessary complexity.  Clearly asking if the Session contains a
>>>> boolean e.g. is complete non-sense.  If JPA requires that condition to
>>>> throw an exception, why even worry about the other case?
>>>>
>>>>
>>>>
>>>>
>>>>> 4. "Accessing Session/EntityManager#getTransaction.  JPA says that is
>>>>> only allowed for JDBC transactions.  Hibernate always allows it." -
>>>>> I'd choose the Hibernate behavior because I don;t see how it can cause any
>>>>> issue and it's an enhancement as well.
>>>>>
>>>>
>>>> Well that's great in principle.  But JPA actually requires an exception
>>>> be thrown when #getTransaction() is called in the JTA case.  So there is no
>>>> simple "just allow it as an extension" solution, we'd have to specific
>>>> allow users to opt-in to allowing that.
>>>>
>>>>
>>>