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RE: [eclipse-incubator-e4-dev] Re: Avoiding Bloat

I have been enjoying reading this exchange. I was going to stay out, but when the subject turned to provisional API I decided to take the time to share some lessons learned the hard way at WTP. I am putting my thoughts in a blog post so that they can be more widely read. Take a look if you are interested. You might even learn what not to do. ;)



Konstantin Komissarchik | Consulting Member of Technical Staff
Phone: +1 425 201 1795 | Mobile: +1 206 898 0611
Oracle Eclipse Tooling
411 108th Ave NE, Suite 2100 | Bellevue, WA 98004


From: eclipse-incubator-e4-dev-bounces@xxxxxxxxxxx [mailto:eclipse-incubator-e4-dev-bounces@xxxxxxxxxxx] On Behalf Of Krzysztof Daniel
Sent: Tuesday, October 21, 2008 2:29 AM
To: E4 developer list
Subject: RE: [eclipse-incubator-e4-dev] Re: Avoiding Bloat


Hi Martin,

The sources you have mentioned also say:
[2] After the API freeze, there is really no such thing as "provisional API". Either it is complete and committed platform API, or it is internal code.
Moreover it reads:
[2] Technically, a provisional API can change arbitrarily or be removed at any time without notice.
I believe that this document indicates that there is strong "API"-"Internal" division after the release (and maybe this is only my interpretation).

In the [4] I have found interesting table:



Test Suite



Support Promise


Platform API












not quite


The table is bigger of course, but only those two cases are important for us. Note the public package in the provisional API. It is contradictory to the [2] unless provisional API becomes API after every release.

I am happy to see that someone is already using provisional API independent from release cycle, even happier that The TPTP project uses Provisional APIs for all new API introductions: the new API is released as provisional in release X and then hardened into platform APIs in release X+1. (4)

Maybe it would be good to ask TPTP team how this approach works in real environment?

What I'd expect from Eclipse is to adopt  slightly modified TPTP strategy - harden provisional API when it has not changed for one development cycle. Provisional API should be in public packages and has clear javadoc that would:
* warn the user that the API *may* change.
* encourage the user to register to particular mailing list/watch some wiki pages

On the other hand we could think about support from API tools, that would throw warnings/errors when the client access provisional API, and about completely new tool that would ask the user to register on mailing list, display messages from developer etc.


Commiter A creates:
package org.eclipse.component;
 * This is provisional API. It is believed to be stable, but still may change. For your own good subscribe to the list component-dev-provisional to be notified about changes.
 * @provisional
 * @since 3.5
public interface IInterface{
        public void method1();
        public void method2();

Now some client implements that interface. It is warned (by API tools) and prompted to register to the newsgroup.  During the development cycle we may ask clients if they got what they expected and if we can do anything better.

Eclipse 3.5 is released. A lot of people uses that interface, and it appears that third method is necessary. So the commiter adds method3(), posts to concrete mailing list and all customers are informed about compatibility breaking change. Also steps necessary to adapt new method are described (and in the future maybe some more advanced refactoring scripts).

Eclipse 3.6 is released with that change, than 3.7 without change, so the @provisional tag should be deleted and... no refactoring at that point :-).

I hope that my vision is easier to understand now :-).

Christopher Daniel        
Technical Support Engineer
Eclipse Support Center    
IBM Software Group      


"Oberhuber, Martin" <Martin.Oberhuber@xxxxxxxxxxxxx>


"E4 developer list" <eclipse-incubator-e4-dev@xxxxxxxxxxx>


2008-10-20 17:43


RE: [eclipse-incubator-e4-dev] Re: Avoiding Bloat


Hi Krzysztof,
I'm afraid that I don't understand what you want to say.
The concept of provisional API in Eclipse exists today. We have provisional
API in releases -- For Debugging, for instance, some provisional API to
support better customization of views has been committed in Eclipse 3.2
and is still provisional as of today. See slide 4 of the EclipseCon 2008 DD
presentation [1] for reference. There are even clients of the provisional
API, but it'll be promoted to official finalized API only once everybody
agrees that it's the right way to go.
The point to be clear about is, that provisional API will always live
in "internal" packages [2]. Once the API promotes to public, existing
clients of the provisional API need to be refactored to the new (non-

internal) namespace. This need for refactoring might be one of the
reasons why some clients are reluctant to adopt provisional API.
Perhaps we'll need to better educate clients here, that this kind of

simple rename refactoring doesn't really hurt that much. The only
thing that it truly requires, is that clients which adopt provisional API
need to be developed along with upcoming Eclipse releases: When
a release makes the API public, the client needs to be updated at
the same time as Eclipse in order to support it.
Note that as per the Eclipse Guidelines, all packages need to be
exported [3]
, internal or not, so everybody can adopt them. This
seems to be exactly what you are requesting?
I agree that we need more feedback on API while it is still provisional,
do you have any ideas for better soliciting such feedback?
[1] EclipseCon 2008 Device Debugging (DD) Update
Martin Oberhuber, Senior Member of Technical Staff, Wind River
Target Management Project Lead, DSDP PMC Member

From: eclipse-incubator-e4-dev-bounces@xxxxxxxxxxx [mailto:eclipse-incubator-e4-dev-bounces@xxxxxxxxxxx] On Behalf Of Krzysztof Daniel
Friday, October 17, 2008 4:10 PM
[eclipse-incubator-e4-dev] Re: Avoiding Bloat

As it was said before there is a huge conflict of interests between developers & adopters.

It is a common guideline, almost requirement, to create new API only where there is at least one consumer. And this is a big problem. A consumer does not have to be an expert in particular area. His requirement may be just a part of bigger functionality, or some not-necessary-adequate point of view. More over, he probably tries to solve his problem, and does not care about quality of Eclipse solution (because commiters do it). So, commiters analyze, code, test, analyze again, discuss, create some more code, and...

...API is finished when there is no more time (This is a lesson learned from API workshop on last EclipseCon).

What happens next? New adopters arrive. Adopters of stable releases, which are believed to be well designed and stable (and they are indeed in most cases). The real, big feedback appears, and API evolves, but due to strict rules it is necessary to maintain binary & contract compatibility.

I believe this is a problem - that the true feedback & adoption occurs after the API is frozen.

Yes, I agree with some previous posts: we certainly need API evolution approach in longer than release cycle and more feedback about provisional API.

I think it would be good to allow provisional API in Eclipse releases and make it stable if the changes during new cycle are small enough.  Of course this solution has certain disadvantages - some code will be unstable despite it is public. At this point we could encourage/force adopters to give us feedback,

It is for their good - the more feedback they give the more chances some functionality will graduate to API.

We could thing also about automatic refactoring scripts or some refactoring tools that would support upgrading to next release. Or just point to critical places in the code and indicate what should be done.

Christopher Daniel        
Technical Support Engineer
Eclipse Support Center    
IBM Software Group      
eclipse-incubator-e4-dev mailing list

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