new convention for hsx project repository names

[John Coomes]

David Holmes (david.holmes at oracle.com) wrote:
> Hi John,
> 
> Can you clarify how the repository name change will affect the actual 
> hotspot version info that is maintained in the repo, and reported via 
> -version and -Xinternalversion.

Hi David,

The new convention only affects the repository names; the version
reported by the JVM will remain the same for now.

Changing the version string is an obvious future step, but since it's
visible to users (not just developers), we have to be a bit more
careful.  Look for more email on that in the coming weeks.

-John

> On 30/08/2013 2:09 PM, John Coomes wrote:
> > The hsx Project has maintained a version number for HotSpot that is
> > distinct from the JDK version--for example HotSpot version hs24 is
> > being delivered into jdk7u40, and hs25 into jdk8.  (For interested
> > readers, some background info about separate versions is included at
> > the end of this message.)
> >
> > The separate version has also been reflected in repository paths, e.g.:
> >
> > 	http://hg.openjdk.java.net/hsx/hsx24
> > 	http://hg.openjdk.java.net/hsx/hsx23
> > 	http://hg.openjdk.java.net/hsx/hsx23.2
> > 	http://hg.openjdk.java.net/hsx/hsx23.4
> > 	...
> >
> > One often-mentioned problem with this naming scheme is that the
> > correspondence between an hsx repository and the JDK release into which
> > it will be delivered is not obvious.  So we are planning on changing the
> > repository naming convention going forward.
> >
> > More precisely, the new repository for HotSpot (and HotSpot-related)
> > changes targeting jdk7u60 and later 7 updates would be:
> >
> > 	http://hg.openjdk.java.net/hsx/jdk7u
> >
> > (The old convention would have used the name http://.../hsx/hsx24.<N>)
> > This new repo will correspond to the jdk7u on-going development repo,
> > i.e., http://hg.openjdk.java.net/jdk7u/jdk7u.
> >
> > Extending this a little into the future, once jdk7u60 reaches a point
> > where a separate stabilization repo is needed, we will create
> > http://hg.openjdk.java.net/hsx/jdk7u60.  At that time the hsx/jdk7u
> > repo would change to target the following jdk7u update release (if
> > there is one).
> >
> > Similar conventions would apply to repositories for jdk8 updates once
> > we have a need for them.
> >
> > Existing hsx repos should continue to be used; in particular, we will
> > continue to use the on-going development repos for the forseeable
> > future:
> >
> > 	http://hg.openjdk.java.net/hsx/hotspot-main
> > 	http://hg.openjdk.java.net/hsx/hotspot-comp
> > 	http://hg.openjdk.java.net/hsx/hotspot-emb
> > 	http://hg.openjdk.java.net/hsx/hotspot-gc
> > 	http://hg.openjdk.java.net/hsx/hotspot-rt
> >
> > These are currently targeting jdk8, and will switch to jdk9 in the near
> > future.  At that point a new jdk8 stabilization repo would be created:
> >
> > 	http://hg.openjdk.java.net/hsx/jdk8
> >
> > to be used instead of the existing hsx/hsx25 repo (hsx/hsx25 is
> > currently used only by the hotspot gatekeeper, Alejandro Murillo).
> >
> > Despite the length of this message, I think the naming change is
> > straightforward and will (slightly) simplify HotSpot development.
> > Since there are already HotSpot changes pending for jdk7u60, I want to
> > create the new repo within the next few days.  If you have questions
> > or feedback, please follow-up on the list.
> >
> > Background on the separate HotSpot version number:
> >
> > Because the same HotSpot source has been delivered simultaneously into
> > multiple JDK releases (e.g., builds of hs23 were delivered into jdk8 and
> > into jdk7u4, builds of hs22 were delivered into early jdk8 builds and
> > into jdk7u2, and so on), a separate HotSpot version facilitated tracking
> > the sources as they propagated to different releases.  But at the same
> > time, it also imposed the overhead of having to map from a HotSpot
> > version to a JDK version and back again.  This is not always simple,
> > particularly for those that do not work with HotSpot on a day-to-day
> > basis.
> >
> > More recent hsx versions (hs24 and hs25), have really targeted only a
> > single JDK release (although a few builds of hs24 did go into both jdk8
> > and into jdk7u<N>).  We expect this trend to continue, and thus the
> > overhead of mapping from a HotSpot version to a JDK version is
> > unnecessary.
> >
> > -John
> >