RFR: 8325621: Improve jspawnhelper version checks

[Aleksey Shipilev]

On Mon, 11 Mar 2024 18:56:21 GMT, Bernd <duke at openjdk.org> wrote:

> with a protocol version you don’t have to care about micro versions and also it is more tolerant about the usual cpu updates which do not introduce incompatibilities most of the time.

I think we can only reasonably guarantee that jspawnhelper built for a particular JDK is compatible. Protocol version does not exactly capture that: there might be a slight change in JDK that jspawnhelper needs to be aware about, but which does not readily manifest in handshake protocol. Version quadruplet seems to get us what we want automatically. Plus, as you said, protocol number would probably communicate a wrong message that there is some guarantee about the protocol.

> btw just as a datapoint: we run into this issue with a longrunning Gerrit server which could no longer invoke external ssh client for incoming hooks (ad did not log this). It was not expected to use the system-vm which was updated on the running system by ubuntu.

Ouch!

-------------

PR Comment: https://git.openjdk.org/jdk/pull/18204#issuecomment-1989231670