RFR: 8284772: GHA: Use GCC Major Version Dependencies Only

[Erik Joelsson]

On Tue, 22 Aug 2023 02:14:54 GMT, Andrew John Hughes <andrew at openjdk.org> wrote:

> GHA regularly breaks because we specify a very explicit GCC version, even down to the release versioning of the Ubuntu package.  In just this last week, it has caused issues with the testing of PRs on 11u (https://github.com/openjdk/jdk11u-dev/pull/2084) and 17u (https://github.com/openjdk/jdk17u-dev/pull/1672)
> 
> Rather than bumping this yet again like [JDK-8313428](https://bugs.openjdk.org/browse/JDK-8313428), this PR suggests dropping the specific version as we did some time ago in 8u and have now done in 11u (https://github.com/openjdk/jdk11u-dev/pull/2087). The requirement still specifies a specific major version of GCC. It just means the dependency isn't broken every time Ubuntu bumps to a new minor release or even just makes a minor change to the package alone.
> 
> Note that the current setup does not guarantee sticking with an exact version of GCC anyway, because - as seen by recent GHA breakage - older versions get removed from the package repository. All we get from this exact version requirement is sporadic breakage of testing and developer time wasted fixing & reviewing (and, in the case of backport trees, approving). If we truly want a static version of GCC, we need to provide our own - or maybe even a full devkit - as we do with the JDK.

In principle I very much prefer locking down dependency versions to keep the build as reliable as possible. Unfortunately, as we have experienced so far, this isn't possible with GHA because the exact package versions aren't kept available for very long. I suppose it would be possible with very diligent watching for new versions and manually testing and updating before the old version disappears, but that doesn't seem feasible in practice. On the other hand, I don't think we have actually seen any problems when bumping the versions so far, so I'm now inclined to agree with this change.

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Marked as reviewed by erikj (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15374#pullrequestreview-1589406551