Cannot find -lhp on Ubuntu or other distributions

[sogaiu]

Describe the bug
Possibly pilot error, but failing to complete "Build from source" instructions.

Reproducing
Assuming an appropriate Ubuntu 19.10 installation:

1. Install opam (either via apt or from opam's repository using the make cold-install approach)
2. opam init
3. eval $(opam env)
4. opam switch create 4.09.0 4.09.0
5. eval $(opam env)
6. sudo apt-get install pkg-config libpcre3-dev
7. git clone https://github.com/comby-tools/comby
8. cd comby && opam install . --deps-only -y
9. eval $(opam env)
10. make

Observe error output ending in:

/usr/bin/ld: cannot find -lhp
collect2: error: ld returned 1 exit status
File "caml_startup", line 1:
Error: Error during linking
make: *** [Makefile:4: build] Error 1

See attached output below for more details.

Expected behavior
The make step completing without error.

Additional context
Output from make step should be attached.

make-output.txt

For the version of opam installed via apt:

$ opam --version
2.0.5

After some searching I'm guessing that -lhp refers to hack_parallel. Does that seem right?

I also tried installation on an Arch-derivative distribution with similar results.

[rvantonder]

Hey--thanks for the report. I ran into this but haven't had a chance to find out what changed to cause it. But yes, basically the static library for hack_parallel (lhp) isn't being picked up (it's not on the path) despite doing eval $(opam env) on Ubuntu or others (AFAIK this doesn't happen on Mac). So this is something I still need to look into. For now, you can get around this by doing, e.g.:

eval $(opam env)
LIBRARY_PATH=$OPAM_SWITCH_PREFIX/lib/hack_parallel opam exec -- dune build

instead of make. I'll keep this issue open until I've pinned down a better workaround.

[sogaiu]

Thanks!

The suggested work-around did it.

It's working well 👍

[rvantonder]

OK so it turns out that the static library is not being packaged in a way that dune (I think as of v2?) can pick it up. rvantonder/hack_parallel#14 will fix this.

[sogaiu]

Thanks for the heads up. Good to hear that a fix may be coming 👍

[rvantonder]

Should be fixed now when building from source, via 46bdbcf.

[sogaiu]

Unfortunately, I now get this:

$ make
dune build --profile dev
File "lib/language/omega_rule.ml", line 242, characters 4-11:
242 |   | Ok rule -> Or_error.return rule
          ^^^^^^^
Error: This pattern matches values of type ('a, 'b) Stdlib.result
       but a pattern was expected which matches values of type
         consume:Consume.t -> (expression list, string) Stdlib.result
File "lib/rewriter/rewrite_template.ml", line 22, characters 4-12:
22 |   | Ok label -> List.find_map label ~f:ident
         ^^^^^^^^
Error: This pattern matches values of type ('a, 'b) result
       but a pattern was expected which matches values of type
         consume:Consume.t -> (string option list, string) result
File "lib/matchers/omega.ml", line 333, characters 12-19:
333 |           | Error _ ->
                  ^^^^^^^
Error: This pattern matches values of type ('b, 'c) result
       but a pattern was expected which matches values of type
         consume:Consume.t -> (Omega.production * 'a, string) result
make: *** [Makefile:4: build] Error 1

I will file another issue.