I'm certainly sympathetic to you thinking here. Having qualifiers in
import statements is ugly at best. The challenge is that in the dev
cycle the API of something may change many many times. This would lead
to quite visible changes in unreasonable ways. For example, say we
introduce some API and then "break" it several times as we refine in
the dev cycle. Then the first release of the API might have version
42.23.27 or some such. Trying to manage API semantics during the
dev/release cycle seems like overkill. Clearly that is an over done
example but you get the point I hope.
Lets step back for a second. Some goals in decreasing order of
priority/importance.
Goal #1: ensure that at least all API packages have version numbers on
the exports.
Goal #2: be able to eat our own dog food wrt provisioning and version
management during the dev cycle.
Good news is that #1 is likely agreed to and *all* we have to do is put
the initial version numbers on the current packages and then have the
tooling help people manage them according to the current versioning
model.
The proposal for using .qualifier was actually one possible
implementation of goal #2. #2 is interesting because eating our own
dog food seems to greatly increase the likelihood of our technology
being good/useful. Without some sort of increasing version number on
the packages, p2 for example, will have a hard time figuring out what
to give you cause everything will look the same to it.
Can anyone think of another way of enabling #2? Of the top of my head
I'm thinking that something like the odd/even version pattern might
help...
Jeff
BJ Hargrave wrote:
If you change API during dev cycle,
that is the proper time to also change the major or minor version.
That
is the whole point. I would assume that API tooling will complain until
you do so. Just changing the qualifier is insufficient to capture an
API
change. Also, I think that last thing we want to see are bundles using
qualifiers in import package statements! So if you use qualifier to
denote
API change during dev, then other bundles will need to import using
qualifiers
to ensure they wire to the desire API if they use it. UGLY!
Qualifiers are useful to capture
implementation
changes. But API is a specified thing that changes deliberately and
(hopefully)
slowly and its version is not subject to implementation.
--
I understand your hestiation and actually agree with
you
from the "released code" point of view. However, we spend
a lot of time dealing with code and API that is in development. If
we are to have any hope of provisioning and managing that, we need to
know
the difference between the various iterations of the packages. For
example, when someone adds an API during the dev cycle and you want use
it, you need to import the right version of the package to ensure you
get
it. Changing the first three segments version number of the package
for every change done in the dev cycle feels too disruptive.
To a certain extent this could be handled in the provisioning system
but
that would force the situation of bundles in a particular context
(e.g.,
a build "lineup"). That is, bundles would no longer be
completely/accurately self-describing.
Jeff
BJ Hargrave wrote:
I would be extremely cautious about using qualifier on package
versions.
I must say that I have never seen it done.
It seems an over specification. I think that having build tools to
advise
you to increment the micro is more than sufficient.
--
| From:
|
Thomas
Watson/Austin/IBM@IBMUS
|
| To:
|
Equinox development
mailing list <equinox-dev@xxxxxxxxxxx>
|
| Date:
|
2008/09/02 10:45 AM
|
| Subject:
|
Re: [equinox-dev]
.qualifier for export
package? |
Before recommending every package uses a qualifier I have the following
concerns:
1) In Eclipse we have loads of packages. We better make sure all
identical
qualifier Strings are shared (interned etc.) for performance reasons.
Today
when loading from a cached state we share identical Version objects.
Because
package versions are managed independently we will end up with lots of
different versions that have the same qualifier exported by a bundle.
We
also will limit the ability to share Version objects across bundles
because
each will use a different qualifier (unless we happen to use the same
CVS
tag).
2) The qualifier will change even in cases where no code was touched in
the package. I'm not sure this is a valid concern. The code got
recompiled
so perhaps changing the version qualifier is warranted. But we need to
think about the consequences. For example, I can see API tooling start
to complain that the micro version of a package should be increased to
indicate a bug "fix" when comparing the package versions with
a base line. It will notice that the qualifier changed from a previous
release but the micro version was not increased.
3) What about versions of packages which we do not maintain the API for
at Eclipse. Things like org.osgi.* and orbit bundles. Shouldn't we use
the version the producers of the API have defined? Adding a qualifier
here
does not seem right, especially if a qualifier is already defined by
the
producers.
On the surface this sounds like a fine idea, and I am not completely
against
it. But I would like to take the first step of versioning the Eclipse
API
packages first to see what all the issues are with independent package
versioning. I'm sure we will run into other hurdles along the way. For
example, how does a developer maintain the version of a split package
across
all the bundles the package is split?
Tom
 "Chris
Aniszczyk" ---08/31/2008 02:46:34 PM---On Sun, Aug 31, 2008 at 5:53
AM, Jeff McAffer < jeff@xxxxxxxxx
On Sun, Aug 31, 2008 at 5:53 AM, Jeff McAffer <jeff@xxxxxxxxx>
wrote:
As version numbers on packages become more prevalent does it start
making
sense to use .qualifier on them in addition to bundle version numbers?
The logic here is the same as for bundles. we rev the version number of
the bundle to match the most extreme change for that release. in
between
if hte provisioning system is going to do its job, it needs to have
different
version numbers. Teh .qualifier allows for the auto-qualification of
bundle
version numbers. The same is true for folks using import/export package.
+1
In PDE, I plan on releasing some builder logic to flag exported
packages
without versions with a warning in M2. API Tooling also has items in
plan
that deal with package versioning, but that will be post M2
Thoughts for how/if this should be introduced?
I say before M2, we formulate a plan across the Eclipse proper projects
to deal with versions on package exports. We can than look at pushing
that
plan to other Eclipse.org projects as a best practice once we get the
hang
of it.
--
Cheers,
~ Chris Aniszczyk_______________________________________________
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