_build in alt-ergo-lib-2.3.2 release

[shakthimaan]

I am trying to build alt-ergo-lib.2.3.2 with dune.2.6.0 and Multicore OCaml 4.10.0 as part of https://github.com/ocaml-bench/sandmark. We use bwrap sandboxing to build packages in a different directory, but, I see that the 2.3.2 release already has a _build/ directory in the release package. Hence, I get the following error when trying to compile alt-ergo-lib.2.3.2:

# [ERROR] ../sandmark/_opam exists, but does not appear to be a valid opam root. Please remove it and use `opam init', or specify a different `--root' argument
# Exception: End_of_file.

Is it possible to provide a tarball without the _build directory, or is there a way to clean the _build directory before running configure?

[ACoquereau]

Hi,
I forgot to clean the _build directory in the release package, sorry for that.
Does the archive (https://github.com/OCamlPro/alt-ergo/archive/2.3.2.tar.gz) from the release package in github does the job ? It should not contain the _build directory

[shakthimaan]

The https://github.com/OCamlPro/alt-ergo/archive/2.3.2.tar.gz has the configure and OPAM files in a sources/ directory, as compared to http://alt-ergo.ocamlpro.com/http/alt-ergo-2.3.2/alt-ergo-2.3.2.tar.gz where they are present in the top-level directory. Would it be possible to make a 2.3.3 minor release without the _build directory?

[ACoquereau]

The release should be done with the PR 16943(ocaml/opam-repository#16943) in opam-repository
You can also find the corrected archive here : https://alt-ergo.ocamlpro.com/http/alt-ergo-2.3.3/alt-ergo-2.3.3.tar.gz
Hope this will resolve your issue.

[shakthimaan]

In the configure script, ocaml unix.cma configure "$@" gets invoked, and I used the following to debug the error:

$ OPAMROOT=/local/sandmark/_opam /local/sandmark/_opam/opam-init/hooks/sandbox.sh build ./configure alt-ergo-lib

The following function in configure.ml is throwing the error for _opam exists, but does not appear to be a valid opam root..

(* Compute actual values for config options *)
let () =
  let prefix_set = !prefix ≠ "" in
  update "prefix" prefix (fun () -> opam_var "prefix");
  update "libdir" libdir (fun () ->
      if prefix_set
      then Filename.concat !prefix "lib"
      else opam_var "lib");
  update "sharedir" sharedir (fun () ->
      if prefix_set
      then Filename.concat !prefix "share"
      else opam_var "share");
  update "mandir" mandir (fun () ->
      if prefix_set
      then Filename.concat !prefix "man"
      else opam_var "man");
  update "pluginsdir" pluginsdir (fun () ->
      Filename.concat
        (Filename.concat !libdir "alt-ergo") "plugins"
    );
  update "preludesdir" preludesdir (fun () ->
      Filename.concat
        (Filename.concat !sharedir "alt-ergo") "preludes"
    );
  ()

The minimal example below suffices to throw the error:

(* Compute actual values for config options *)
let () =
  let prefix_set = !prefix ≠ "" in
  update "prefix" prefix (fun () -> opam_var "prefix");
  ()

What could be a possible fix?
Note: The version number in the *.opam files need to be bumped to use 2.3.3.

[ACoquereau]

#353 will make the release 2.3.3. I'll let @Gbury handle the _opam issue. When this will be done we will make the 2.3.3 release in the opam repository

[Gbury]

Since a few versions, opam has a concept of local switches (as in, local to a directory). Such local switches are stored in a folder named _opam in the directory of the switch, and thus to determine the current switch, opam looks for a _opam file in the parents directory of the current directory. I think here what happens is that you may use _opam for something else than a local switch, and hence when the configure script calls opam for some config variables, and opam looks for the current switch, it finds a _opam that is not a local switch, and hence errors out.
There is not much that can be done from the alt-ergo side, but I see two solutions:

• do not use the name _opam for something else than a local-switch (such folders are automatically created by opam, so just consider the name as reserved by opam, just as ~/.opam is)
• call the configure script with explicit values for all configurable parameters (prefix, libdir, mandir), which should skip the opam invocation.

[ACoquereau]

2.3.3 has been released, hope everything work for you @shakthimaan

[shakthimaan]

Yes, specifying prefix, and libdir to configure script helped build alt-ergo in the sandbox environment. Thanks @OCamlPro-Coquera and @Gbury.