Add plugin flag to opam-0install

[dra27]

No description provided.

[talex5]

What's this for? I thought the solver was available as a built-in now anyway?

[dra27]

The opam package is named opam-0install which means it's capable of being invoked as a plugin (i.e. as opam 0install with opam automatically delegating the command line to it) and we (opam) had a bug report with it being used that way, so I assumed it intended to be used as a plugin?

There may be errors in assumption at any stage of this!

[dra27]

I was following a regression related to ocaml/opam#4554 - the command shown in there doesn't work in opam 2.1 because opam 2.1 is more pernickety about the plugin flag being specified than opam 2.0.

[talex5]

Hmm. It's not supposed to be used as a plugin!

That command doesn't work for me in opam 2.0 either, though:

$ docker run --rm -it ocaml/opam
opam@7a58ad95d269:~$ opam --version
2.0.10
opam@7a58ad95d269:~$ opam 0install dune
[ERROR] 0install is not a known command or plugin (package opam-0install.0.4.2 does not have the 'plugin' flag set).

Maybe it's a typo in the issue?

[dra27]

Ah, my bad - in which case this and the opam-repository PR can be closed, and sorry for the noise!