[news.eclipse.technology.equinox] Re: Self Hosting Thread

["Jeff McAffer" <jeff_mcaffer_REMOVE@xxxxxxxxxx>]

"Olivier Gruber" <ogruber@xxxxxxxxxx> wrote in message
news:b3dt4n$6js$1@xxxxxxxxxxxxxxxx
> Because features are logical groupings of plug-ins and fragments,
> a project (plug-in or fragment) may have to be built several times
> for different target environments... not only OS,WM, and ARCH
> but also different feature profiles.  One word about feature profiles.
> When a feature F assumes a feature profile, it is a set of features
> that allows to satisfy the dependencies of the plug-ins of F .
> This does not mean that the feature F will only run if those features
> from the feature profile are present; it means that those features will
> contribute the necessary plug-ins to fulfill the plug-in dependencies of
> feature F.

There is a failure if this is true.  There is no magic here.  An individual
plugin/fragment can be compiled if all the required classes can be found at
compile time.  Assuming that the class definitions do not change, how they
are compiled has no bearing on how they are run.  This is standard Java
stuff.  So with a strong commitment to APIs and compatibility, one can
successfully compile their plugin against one configuration of plugins and
run against another.

The only time a plugin might need to be built multiple times is if it has
some OS/WS/ARCH dependency.  In general the approach there has been to
separate those dependencies into fragments which are specific to that
configuration.  Java (or Eclipse) does not support any conditional
building/compiling so rebuilding multiple times would likely yield the same
result each time.

> However, the update manager does not allow to install back-level
> features (Eclipse 2.1). This is very limiting to work across versions.
> This is pretty annoying when one needs to fix a bug on a plug-in for
> a back-level Eclipse... he has to work in a back-level Eclipse as a
> hosting environment. Things are made worse if one considers that
> the host environment (OS,WM,ARCH) may differ from the target
> one.

I don't understand this.  You can target whatever version of Eclipse you
want.  We do this all the time.  I know whole development teams that use 2.1
to develop 2.0 based products.

> That said, I understand that getting a self-hosting environment
> is difficult and Eclipse is certainly a great first pass at it. I simply
> believe that Equinox should make it a priority to improve on
> self-hosting because it would be such an attractive feature,
> pun intended, for future releases of Eclipse.

To rephrase, Equinox should make it a priority to understand the issues and
explore directions, and interest the Eclipse team in those results.  I
believe that the bulk of the work is stuff that the PDE team (in particular)
is very interested in doing.

Jeff