Proposal to use hgupdate-sync label on bugs synced from JDK 9 to JDK 10

[joe darcy]

Hello,

With the policy of fixes in JDK 9 being periodically synced into JDK 10 
[1], the set of bugs in JBS and set of changesets in the JDK 10 forests 
will include both fixes unique and newly introduced to JDK 10 as well as 
hundreds of fixes "just" forward-ported from JDK 9.

A similar situation occurs in the update release train when fixes from 
the stabilization forest are pulled into the always-open forest. The bug 
tracking in the update releases is assisted by use of the 
"hgupdate-sync" label: "The 'hgupdate-sync' label is used to denote bug 
records which are already fixed in a previous release. When code lines 
are synced a new backport record will be created with the hgupdate-sync 
label to capture the sync activity. For the most part, such records can 
be ignored since they indicate that the issue was resolved in an earlier 
update release." [2]

For a particular example, the bug JDK-6515172: 
"Runtime.availableProcessors() ignores Linux taskset command" has 
several backports into the 8 update family. The earliest 8 update 
release with a backport is 8u121; there is no hgupdate-sync label in 
that case. However, when the fix was subsequently applied to 8u131 and 
8u152, the backports created for those releases have the hgupdate-sync 
label:

     8u121:    https://bugs.openjdk.java.net/browse/JDK-8173345
     8u131:    https://bugs.openjdk.java.net/browse/JDK-8174019 
hgupdate-sync
     8u152:    https://bugs.openjdk.java.net/browse/JDK-8166105 
hgupdate-sync

When the pushes/syncs into 8u131 and 8u152 occurred, Hg-updater saw that 
the bug was already fixed in an earlier 8uX release and thus added the 
hgupdate-sync label to the newly-created backports. The fixes unique to 
a release are (roughly) all the fixes with that fixVersion minus the 
fixes with the hgupdate-sync label.

The same convention may be helpful to follow for the bugs synced from 
JDK 9 into JDK 10. Some small changes to Hg-updater would be necessary 
to implement this policy since currently hgupdate-sync will only be 
applied to fixes within the same update release family. A bulk edit 
could be done to add the label retroactively to the JDK 9 changes 
recently synced into JDK 10.

Comments?

Thanks,

-Joe

[1] 
http://mail.openjdk.java.net/pipermail/jdk10-dev/2017-February/000054.html

[2] https://wiki.openjdk.java.net/display/general/JBS+Overview