problem with OCAMLFIND_DESTDIR and OCAMLPATH

[sweeks]

If I have OCAMLFIND_DESTDIR and OCAMLPATH set in my environment, then
opam install res fails with the complaint below:

[ERROR] while installing res.3.2.0
= [RUN] "make install"
...
. Installing library with ocamlfind
. ocamlfind install  res META res.mli strat.mli pres_intf.mli nopres_intf.mli strat.cmi pres_intf.cmi nopres_intf.cmi weak_intf.cmi res.cmi res.cma res.cmxa res.a
. make[1]: Leaving directory `/mnt/local/janevg-data/sweeks/dot-opam/jane-elisp/build/res.3.2.0/lib'
* ocamlfind: Bad configuration: Cannot mkdir /home/sweeks/lib/ocaml-site-lib/res because a path component does not exist or is not a directory
* make[1]: *** [libinstall] Error 2
* make: *** [install] Error 2
  'opam install res' failed

I did run eval $(opam config -env), but I see that isn't setting (or
clearing) those variables.

[avsm]

Fixing this comprehensively either requires enumerating all the environment variables which might affect compilation (there are a lot) and overriding them, or by not inheriting any of the parent shell variables and specifically setting them in any OPAM-invoked shells.

The latter is somewhat more preferable in terms of deterministic output, but would need some support for the user to override some env variables (e.g. to support http://caml.inria.fr/mantis/view.php?id=5723 )

[sweeks]

Not inheriting parent shell variables sounds good.

I'm probably being naive, but I don't understand why that would
require changes to the OCaml tools (issue 5723). There is currently
some set of environment variables that are allowing me right now to
build the packages I am using. It seems to me that setting just that
set is sufficient, without any changes to OCaml tools.

[avsm]

Right, mandating a specific set of environment variables would be
fine, but it might be too limiting. Sometimes the user wants to
specify an extra variable to be sett (e.g., to globally activate
-g or -p in all pkgs). You can't do this with the current ocaml tools,
but the Mantis issue I linked proposes an env variable that ocamlc
picks up instead of laboriously going through all the Makefiles.

Although, it occurs to me that you can also already do this via compiler
spec files (which can include extra variables for that particular switch).
So it may be sufficient to simply not inherit environment variables.

-anil

On 17 Sep 2012, at 20:31, Stephen Weeks notifications@github.com wrote:

Not inheriting parent shell variables sounds good.

I'm probably being naive, but I don't understand why that would
require changes to the OCaml tools (issue 5723). There is currently
some set of environment variables that are allowing me right now to
build the packages I am using. It seems to me that setting just that
set is sufficient, without any changes to OCaml tools.

—
Reply to this email directly or view it on GitHub.

[samoht]

You seem not to be the first one to hit this issue, so I guess we should do something about it. Maybe starting from a fresh environment is the right way to go. And yes, for the compiler env variables, the right way to define them is in the compiler description files.

[samoht]

This should be fixed in 0.7. OPAM now displays a warning if the wrong environment variables are set.

[xavierleroy]

The recently-reported issue ocaml/Zarith#136 might be an instance of this old problem. I'll let you decide. [ Edit: fixed the URL ].