opam switch create 5.0.0 fails

[fpottier]

Hello,
The creation of a fresh 5.0.0 switch fails with the following error message. I have just run opam update and I have removed the pre-existing 5.0.0 switch prior to running opam switch create 5.0.0. I am running MacOS with an Apple processor.

⬇ retrieved ocaml-config.3  (cached)
∗ installed base-bigarray.base
∗ installed base-threads.base
∗ installed base-unix.base
∗ installed host-arch-arm64.1
∗ installed host-system-other.1
∗ installed ocaml-options-vanilla.1
⬇ retrieved ocaml-base-compiler.5.0.0  (cached)
∗ installed ocaml-base-compiler.5.0.0
∗ installed ocaml-config.3
[ERROR] The compilation of ocaml.5.0.0 failed at "ocaml
        /Users/fpottier/.opam/5.0.0/share/ocaml-config/gen_ocaml_config.ml
        5.0.0 ocaml".

#=== ERROR while compiling ocaml.5.0.0 ========================================#
# context     2.1.5 | macos/arm64 | ocaml-base-compiler.5.0.0 | https://opam.ocaml.org#25082ca0
# path        ~/.opam/5.0.0/.opam-switch/build/ocaml.5.0.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build ocaml /Users/fpottier/.opam/5.0.0/share/ocaml-config/gen_ocaml_config.ml 5.0.0 ocaml
# exit-code   2
# env-file    ~/.opam/log/ocaml-68161-44c623.env
# output-file ~/.opam/log/ocaml-68161-44c623.out
### output ###
# Cannot find file /Users/fpottier/.opam/5.0.0/share/ocaml-config/gen_ocaml_config.ml.

[fpottier]

And running opam 2.1.6.

[fpottier]

Actually, I am seeing a similar problem with 5.2.0...

[rleonid]

I've also tried several switches and the problem seems to be that either the share or ocaml-config directory in ~/.opam/<switch>share/ocaml-config/gen_ocaml_config.ml is not created or correctly unpacked.

[hannesm]

Dear @fpottier and @rleonid, sorry for your inconvenience.

It seems to be caused by the removal of files, and discussed in #25961 and https://discuss.ocaml.org/t/the-compilation-of-ocaml-5-1-1-failed-at-ocaml-gen-ocaml-config-ml-5-1-1-ocaml/14731

So, the quick workaround: rm -rf ~/.opam/repo/default{,.tar.gz} && opam update default -- in the long run, ensure that you have a GNU patch installed (via homebrew or macports).

[fpottier]

Thanks @hannesm for the work-around, which worked. I had installed gpatch already but did not know how to fix my broken state. I am closing this issue.

[rleonid]

Thank you @hannesm !!!