Fix the conflict with the environment variable name used by dune

[smorimoto]

As the title says. This is a bug that was found while investigating ocaml/dune#4166.

Related issue: #4068

[rjbou]

Thanks!

[rjbou]

PR to backport in 2.0.9

[smorimoto]

Thank you, too! Is there a timeline for the 2.0.9 release btw?

[rjbou]

The list of backported PRs/fixes is done on the fly, regarding the needs. (and no date set for 2.0.9 yet).

[smorimoto]

Got it, 2.1.0 doesn't seem to be released as early as I thought, so it would be helpful if 2.0.9 be released as soon as possible. (Because once put this change into the stable release, setup-ocaml can use the dune cache to speed up the entire workflow a couple of times.)

[rjbou]

Ok, noted!

[smorimoto]

But definitely there is no rush at all. Please release it at your convenience. Thanks for your effort on opam :)

[rjbou]

Until the release, you can change the sandbox file. It is in ~/.opam/opam-init/hooks/sandbox.sh (or sed it if in stateless scripty).

[smorimoto]

Indeed, I don't really like doing that kind of hack on the action side, but let me create another branch and check it if it works as expected.

[smorimoto]

OK, I replaced the file and it works as expected!