> Should target release be 4.1. (not 4.0.x) ?
No, in my opinion the target should be 4.0.x. We are reaching for a shippable
trunk and this has no public API impacts. This work is IMO central to achieving
a shippable trunk, either way. The only reason I do not target 3.x is that it
would be too burdensome.
> My concern is that changing code and tests at the same time risks regressions…
I’ve never heard this position before. Would you care to elaborate? It is quite
normal for us to update tests alongside changes to the code.
> And seconding Benjamin's comments… some documentation on how to write a test,
> and a simple test example, that this CEP then allows us to write would help a
> lot (a la "working backwards").
1) This work is to _enable_ the development of tests, with the only test
originally planned to arrive alongside it the fairly sophisticated LWT
Verifier. This is something we have sorely needed as a project, as we have had
serious correctness violations for multiple years. This broad category of
integrated test for verifying correctness is the main goal of the work and is
not easily condensed into an example snippet.
2) It is _possible_ that some simple and fluid APIs will be introduced in a
later phase of this work, but they haven’t been designed yet, so I cannot share
snippets.
In principle, however, you would be able to do something like:
@Nemesis volatile int x = 0;
int foo() {
x = x + 1;
return x;
}
@Test
void test() {
Future<?> f1 = executor.submit(() -> foo());
Future<?> f2 = executor.submit(() -> foo());
Assert.assertTrue(f1.get() == 1 || f2.get() == 1);
}
From: Mick Semb Wever <m...@apache.org>
Date: Tuesday, 13 July 2021 at 10:28
To: dev@cassandra.apache.org <dev@cassandra.apache.org>
Subject: Re: [DISCUSS] CEP-10: Cluster and Code Simulations
>
> To achieve this, significant modifications will be required to the codebase,
> mostly cleaning up existing abstractions. Specifically, we will need to be
> able to mock executors, any blocking concurrency primitives, time, filesystem
> access and internode streaming.
>
> The work is – in large part – already complete, with JIRA and PRs to follow
> in the coming weeks. Of course, the work is subject to the usual community
> input and review, so this does not preclude changes to the work (even
> significant ones, if they are warranted). I know a lot of incoming CEP are
> likely to be backed up by significant off-list development as a result of the
> focus on a shippable 4.0. Hopefully this is just a temporary growing pain,
> particularly as we move towards a shippable trunk.
>
> I hope this work will be of huge value to the project, particularly as we
> race to catch up on years of limited feature development.
>
> JIRA and PRs will follow, but I wanted to kick-off discussion in advance.
>
Should target release be 4.1. (not 4.0.x) ?
I'd be interested in seeing a rough timeline/plan of how the proposed
changes are to be defined in JIRAs and ordered.
I'd like to hear a bit more about the test plan. Not so much about how
the CEP itself improves testability of the project, but for example
the testing required to be in place to introduce the changes of the
CEP (and if it already exists, where). My concern is that changing
code and tests at the same time risks regressions…
And seconding Benjamin's comments… some documentation on how to write
a test, and a simple test example, that this CEP then allows us to
write would help a lot (a la "working backwards").
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