Dependency Generation Does Not Include Executables?

[zepalmer]

It seems that, if a BuildDepends entry appears in an Executable but not in a Library, it is not included in the opam file. For instance, my project includes a single library with the following BuildDepends:

  BuildDepends:
    batteries,
    monadlib,
    ocaml-monadic,
    ppx_deriving.std (>= 2.0),
    yojson

It has a single executable with this BuildDepends:

  BuildDepends:
    batteries,
    jhupllib,
    oUnit,
    ppx_deriving.std (>= 2.0),
    ppx_deriving_yojson

The resulting opam file contains this depends entry:

depends: [
  "base-threads"
  "batteries"
  "monadlib"
  "oasis" {build & >= "0.4.7"}
  "ocaml-monadic"
  "ocamlbuild" {build}
  "ocamlfind" {build}
  "ounit" {build}
  "ppx_deriving" {>= "2.0"}
  "yojson"
]

As a result, the OPAM package fails to install unless the user has already manually installed ppx_deriving_yojson. Am I misunderstanding the function of these fields? Is this an oversight?

The above project can be found here. Steps to reproduce:

mkdir -p ztemp
cd ztemp
export OPAMROOT="$(pwd)/opam"
mkdir -p $OPAMROOT
opam init
eval `opam config env`
git clone https://github.com/JHU-PL-Lab/jhu-pl-lib.git
cd jhu-pl-lib
git checkout c901c56ea93640e5aaa0232e6b05000e5f87120b
opam pin add jhupllib .

The last command will fail with an error message something like this:

#=== ERROR while installing jhupllib.0.1+dev ==================================#
# opam-version 1.2.2
# os           linux
# command      ocaml setup.ml -configure --prefix /home/zpalmer/ztemp/opam/4.04.1
# path         /home/zpalmer/ztemp/opam/4.04.1/build/jhupllib.0.1+dev
# compiler     4.04.1
# exit-code    1
# env-file     /home/zpalmer/ztemp/opam/4.04.1/build/jhupllib.0.1+dev/jhupllib-4107-aaa640.env
# stdout-file  /home/zpalmer/ztemp/opam/4.04.1/build/jhupllib.0.1+dev/jhupllib-4107-aaa640.out
# stderr-file  /home/zpalmer/ztemp/opam/4.04.1/build/jhupllib.0.1+dev/jhupllib-4107-aaa640.err
### stderr ###
# ocamlfind: Package `ppx_deriving_yojson' not found

Please let me know if I can provide additional information. Thank you for the tool!