`opam env` does not set OCAMLPATH

[Frigory33]

My system is Manjaro. A lot of packages fail to install in switches other than the default one, for instance menhir or js_of_ocaml-ocamlbuild, with errors such as:

#=== ERROR while compiling js_of_ocaml-ocamlbuild.5.0 =========================#
# context     2.3.0 | linux/x86_64 | ocaml-base-compiler.5.2.1 | https://opam.ocaml.org#d87296a7b656d47b7042e7e608a5fa863b3a51f9
# path        ~/.opam/ocaml-base-compiler.5.2.1/.opam-switch/build/js_of_ocaml-ocamlbuild.5.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p js_of_ocaml-ocamlbuild -j 3 --promote-install-files=false @install
# exit-code   1
# env-file    ~/.opam/log/js_of_ocaml-ocamlbuild-38916-d17c67.env
# output-file ~/.opam/log/js_of_ocaml-ocamlbuild-38916-d17c67.out
### output ###
# (cd _build/default && /home/frigory/.opam/ocaml-base-compiler.5.2.1/bin/ocamlc.opt -w -40 -g -bin-annot -bin-annot-occurrences -I .ocamlbuild_js_of_ocaml.objs/byte -I /home/frigory/.opam/default/lib/ocamlbuild -I /home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/ocaml/str -I /home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/ocaml/unix -no-alias-deps -o .ocamlbuild_js_of_ocaml.objs/byte/ocamlb[...]
# File "ocamlbuild_js_of_ocaml.mli", line 1:
# Error: "/home/frigory/.opam/default/lib/ocamlbuild/ocamlbuild_plugin.cmi"
#        is not a compiled interface for this version of OCaml.
# It seems to be for a newer version of OCaml.

As you can see, it looks like some files are looked for in the default opam switch. There is -I /home/frigory/.opam/default/lib/ocamlbuild in the compilation command. With menhir, I have -I /home/frigory/.opam/default/lib/menhirLib -I /home/frigory/.opam/default/lib/menhirSdk.

Where does this problem come from? I don’t get those errors on Windows: my opam switches work on Windows. But I’m getting this error on my 2 Manjaro systems (which are not in sync).

[kit-ty-kate]

Somehow there seems to be a mixup between the environment of your default switch and your current switch (named ocaml-base-compiler.5.2.1).

Could you show the output of the env, opam env, ocamlc -config and which -a ocamlopt commands?

[Frigory33]

$ env
SHELL=/bin/bash
SESSION_MANAGER=local/Chambsyl-Manjaro:@/tmp/.ICE-unix/1244,unix/Chambsyl-Manjaro:/tmp/.ICE-unix/1244
CAML_LD_LIBRARY_PATH=/home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/stublibs:/home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/ocaml/stublibs:/home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/ocaml
WINDOWID=50331655
OCAML_TOPLEVEL_PATH=/home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/toplevel
COLORTERM=truecolor
OCAMLPATH=/home/frigory/.opam/default/lib
XDG_CONFIG_DIRS=/etc/xdg
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session0
NVM_INC=/home/frigory/.nvm/versions/node/v16.20.2/include/node
HISTCONTROL=ignoredups
XDG_MENU_PREFIX=xfce-
LC_ADDRESS=fr_FR.UTF-8
LC_NAME=fr_FR.UTF-8
SSH_AUTH_SOCK=/tmp/ssh-XXXXXXWnSCOa/agent.1324
GRADLE_HOME=/usr/share/java/gradle
XDG_CONFIG_HOME=/home/frigory/.config
DESKTOP_SESSION=xfce
LC_MONETARY=fr_FR.UTF-8
SSH_AGENT_PID=1325
EDITOR=vim
GTK_MODULES=canberra-gtk-module:canberra-gtk-module
XDG_SEAT=seat0
OCAMLTOP_INCLUDE_PATH=
PWD=/home/frigory
LOGNAME=frigory
XDG_SESSION_DESKTOP=xfce
QT_QPA_PLATFORMTHEME=qt5ct
XDG_SESSION_TYPE=x11
MANPATH=/home/frigory/.nvm/versions/node/v16.20.2/share/man::/home/frigory/.opam/ocaml-base-compiler.5.2.1/man
XAUTHORITY=/home/frigory/.Xauthority
OPAM_SWITCH_PREFIX=/home/frigory/.opam/ocaml-base-compiler.5.2.1
XDG_GREETER_DATA_DIR=/var/lib/lightdm-data/frigory
MOTD_SHOWN=pam
GDM_LANG=fr_FR.utf8
GTK2_RC_FILES=/home/frigory/.gtkrc-2.0
HOME=/home/frigory
LC_PAPER=fr_FR.UTF-8
LANG=fr_FR.utf8
XDG_CURRENT_DESKTOP=XFCE
VTE_VERSION=7803
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
XDG_CACHE_HOME=/home/frigory/.cache
NVM_DIR=/home/frigory/.nvm
XDG_SESSION_CLASS=user
LC_IDENTIFICATION=fr_FR.UTF-8
TERM=xterm-256color
USER=frigory
DISPLAY=:0.0
SHLVL=1
NVM_CD_FLAGS=
LC_TELEPHONE=fr_FR.UTF-8
LC_MEASUREMENT=fr_FR.UTF-8
XDG_VTNR=7
XDG_SESSION_ID=2
LD_LIBRARY_PATH=/home/frigory/.local/lib:/usr/local/lib
XDG_RUNTIME_DIR=/run/user/1000
DEBUGINFOD_URLS=https://debuginfod.archlinux.org 
LC_TIME=fr_FR.UTF-8
XDG_DATA_DIRS=/home/frigory/.local/share/flatpak/exports/share:/var/lib/flatpak/exports/share:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/usr/share
PATH=/home/frigory/.opam/ocaml-base-compiler.5.2.1/bin:/home/frigory/.nvm/versions/node/v16.20.2/bin:/home/frigory/.local/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/opt/android-sdk/platform-tools:/var/lib/flatpak/exports/bin:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/var/lib/snapd/snap/bin
GDMSESSION=xfce
SAL_USE_VCLPLUGIN=gtk
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
NVM_BIN=/home/frigory/.nvm/versions/node/v16.20.2/bin
MAIL=/var/spool/mail/frigory
LC_NUMERIC=fr_FR.UTF-8
OPAM_LAST_ENV=/home/frigory/.opam/.last-env/env-35f680a1cecbd39bc8b85bd8416bf196-0
_=/usr/bin/env

$ opam env
OPAM_LAST_ENV='/home/frigory/.opam/.last-env/env-35f680a1cecbd39bc8b85bd8416bf196-0'; export OPAM_LAST_ENV;
OPAM_SWITCH_PREFIX='/home/frigory/.opam/ocaml-base-compiler.5.2.1'; export OPAM_SWITCH_PREFIX;
CAML_LD_LIBRARY_PATH='/home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/stublibs:/home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/ocaml/stublibs:/home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/ocaml'; export CAML_LD_LIBRARY_PATH;
OCAML_TOPLEVEL_PATH='/home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/toplevel'; export OCAML_TOPLEVEL_PATH;
MANPATH='/home/frigory/.nvm/versions/node/v16.20.2/share/man::/home/frigory/.opam/ocaml-base-compiler.5.2.1/man'; export MANPATH;
PATH='/home/frigory/.opam/ocaml-base-compiler.5.2.1/bin:/home/frigory/.nvm/versions/node/v16.20.2/bin:/home/frigory/.local/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/opt/android-sdk/platform-tools:/var/lib/flatpak/exports/bin:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/var/lib/snapd/snap/bin'; export PATH;

$ ocamlc -config
version: 5.2.1
standard_library_default: /home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/ocaml
standard_library: /home/frigory/.opam/ocaml-base-compiler.5.2.1/lib/ocaml
ccomp_type: cc
c_compiler: gcc
ocamlc_cflags:  -O2 -fno-strict-aliasing -fwrapv -pthread -fPIC  -pthread
ocamlc_cppflags:  -D_FILE_OFFSET_BITS=64 
ocamlopt_cflags:  -O2 -fno-strict-aliasing -fwrapv -pthread -fPIC  -pthread
ocamlopt_cppflags:  -D_FILE_OFFSET_BITS=64 
bytecomp_c_compiler: gcc  -O2 -fno-strict-aliasing -fwrapv -pthread -fPIC  -pthread  -D_FILE_OFFSET_BITS=64 
native_c_compiler: gcc  -O2 -fno-strict-aliasing -fwrapv -pthread -fPIC  -pthread  -D_FILE_OFFSET_BITS=64 
bytecomp_c_libraries: -lzstd  -lm  -lpthread
native_c_libraries:  -lm  -lpthread
native_ldflags: 
native_pack_linker: ld -r -o 
native_compiler: true
architecture: amd64
model: default
int_size: 63
word_size: 64
system: linux
asm: as
asm_cfi_supported: true
with_frame_pointers: false
ext_exe: 
ext_obj: .o
ext_asm: .s
ext_lib: .a
ext_dll: .so
os_type: Unix
default_executable_name: a.out
systhread_supported: true
host: x86_64-pc-linux-gnu
target: x86_64-pc-linux-gnu
flambda: false
safe_string: true
default_safe_string: true
flat_float_array: true
function_sections: true
afl_instrument: false
tsan: false
windows_unicode: false
supports_shared_libraries: true
native_dynlink: true
naked_pointers: false
exec_magic_number: Caml1999X034
cmi_magic_number: Caml1999I034
cmo_magic_number: Caml1999O034
cma_magic_number: Caml1999A034
cmx_magic_number: Caml1999Y034
cmxa_magic_number: Caml1999Z034
ast_impl_magic_number: Caml1999M034
ast_intf_magic_number: Caml1999N034
cmxs_magic_number: Caml1999D034
cmt_magic_number: Caml1999T034
linear_magic_number: Caml1999L034

$ which -a ocamlopt
/home/frigory/.opam/ocaml-base-compiler.5.2.1/bin/ocamlopt
/usr/bin/ocamlopt
/bin/ocamlopt

[Frigory33]

Indeed, the culprit is OCAMLPATH which is set in my .bashrc… I didn’t notice it! And I don’t remember why I set this variable. If I set it to the right value, things work.

Why isn’t this variable set by opam env?

[Frigory33]

OK, so this is about setting automatically OCAMLPATH by opam env to avoid such messes. Do you think it would be a good idea?