Switch jdk7u development to Git/Skara

[erik.joelsson at oracle.com]

Hello jdk7u maintainers,

I would like to raise the subject of potentially moving jdk7u 
development over to Github/Skara at some point in the future. Currently 
the only 2 projects still on hg.openjdk.java.net are jdk7u and jdk8u, 
and we are currently in the process of figuring out the migration path 
for jdk8u [1]. If the current plan holds, then in April 2022, jdk7u will 
be the only project left. I don't know how long jdk7u will stay active, 
but even if it's for a limited time, the move would be greatly 
appreciated from an infrastructure support point of view.

The move for 7u is similar to 8u and a bit trickier than the previous 
move of 11u. We first need to consolidate the Mercurial repositories 
into one, like we did for 10. I have already produced a prototype 
conversion, both of a consolidated HG repo [2] and then also to Github 
[3]. In the jdk8u plan, we are aiming for a separate forest 
consolidation step in November, followed by a two step move to Git in 
February and April respectively. We can do the same thing for 7u, or we 
can do it all in one step. Note that the consolidation is the step that 
has the most potential for down time. I would recommend planning for a 
full week just in case something goes wrong, though expected time is 
more likely around 1-2 days.

I would like to hear from the maintainers of jdk7u what your preferred 
strategy would be and what timelines would potentially work for you.

/Erik

[1] 
https://mail.openjdk.java.net/pipermail/jdk8u-dev/2021-October/014316.html
[2] http://hg.openjdk.java.net/jdk7u/consol-proto/
[3] https://github.com/openjdk/jdk7u