Opam sandboxing issues

[reynir]

On a new opam switch in the master branch of conan I get the following error when installing conan:

Entering directory '/home/reynir/workspace/conan'
Copying to _destdir/home/reynir/workspace/conan/_opam/lib/conan/META
Error: mkdir(_destdir): Read-only file system

While in another opam switch installing conan from opam results in a different but related error:

Entering directory '/home/reynir/workspace/builder-web'
Error: Unknown package conan!
Fatal error: exception Sys_error("_build/.filesystem-clock: Read-only file system")
Raised by primitive operation at Stdlib.open_out_gen in file "stdlib.ml", line 331, characters 29-55
Called from Stdune__io.Make.with_file_out in file "otherlibs/stdune/io.ml", line 102, characters 17-43
Called from Dune_engine__cached_digest.get_current_filesystem_time in file "src/dune_engine/cached_digest.ml", line 80, characters 2-38
Called from Dune_engine__cached_digest.delete_very_recent_entries in file "src/dune_engine/cached_digest.ml", line 94, characters 12-42
Called from Dune_engine__cached_digest.dump.(fun) in file "src/dune_engine/cached_digest.ml", line 117, characters 8-37
Called from Stdune__exn.protectx in file "otherlibs/stdune/exn.ml", line 12, characters 8-11
Re-raised at Stdune__exn.protectx in file "otherlibs/stdune/exn.ml", line 18, characters 4-11
Called from Stdlib.at_exit.new_exit in file "stdlib.ml", line 560, characters 59-63
Called from Stdlib.do_at_exit in file "stdlib.ml" (inlined), line 566, characters 20-61
Called from Stdlib.exit in file "stdlib.ml", line 569, characters 2-15
Called from Main in file "bin/main.ml", line 100, characters 4-10

[reynir]

For _destdir I found out reading dune install --help that dune install --create-install-files creates _destdir:

   --create-install-files
       Do not directly install, but create install files in the root
       directory and create substituted files if needed in destdir
       (_destdir by default)

I don't know what this does, if it's necessary, and maybe we can get away with adding in the opam file

install: ["dune" "install"]

The same dune install --create-install-files invocation is present in conan.0.2.0 in opam repository.

[dinosaure]

I mainly followed this tutorial from dune: https://dune.readthedocs.io/en/stable/sites.html?highlight=create-install-files#installation. And it says that we must add the --create-install-files. Probably @rgrinberg has a better knowledge than me about your error and my usage of dune-site.

[tmcgilchrist]

Similar but different error installing on macOS (Monterey) opam 2.1.4 and ocaml 4.14.1.

$ opam install conan
The following actions will be performed:
  ∗ install conan 0.0.2

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><>  🐫 
⬇ retrieved conan.0.0.2  (cached)
[ERROR] The compilation of conan.0.0.2 failed at "dune install --create-install-files conan".

#=== ERROR while compiling conan.0.0.2 ========================================#
# context     2.1.4 | macos/x86_64 | ocaml-base-compiler.4.14.1 | https://opam.ocaml.org/#26770281
# path        ~/code/ocaml/ocamlot/_opam/.opam-switch/build/conan.0.0.2
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune install --create-install-files conan
# exit-code   1
# env-file    ~/.opam/log/conan-14922-5c5eb5.env
# output-file ~/.opam/log/conan-14922-5c5eb5.out
### output ###
# Error: Unknown package conan!



<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><>  🐫 
┌─ The following actions failed
│ λ build conan 0.0.2
└─ 
╶─ No changes have been performed

[dinosaure]

I will try to look deeper on this issue, however, I suspect a dune issue here. Let me confirm that.

[reynir]

Hi, I did a git grep -- --create-install-files in opam-repository, and all other occurences add as well "-p" name" in the invocation. I will test if this fixes it for me and submit a PR.