opam pin failure on janestreet's packages

[Ninjapouet]

Hi,

I've a strange behavior using the current opam 2.0.0~rc:

$  opam pin add --debug -n -vvv ocaml-compiler-libs v0.10.0
00:00.001  GSTATE                  LOAD-GLOBAL-STATE @ /home/blond/.opam
00:00.001  RSTATE                  LOAD-REPOSITORY-STATE @ /home/blond/.opam
00:00.084  RSTATE                  Loaded /home/blond/.opam/repo/state.cache in 0.081s
00:00.206  RSTATE                  Cache found
00:00.206  STATE                   LOAD-SWITCH-STATE @ 4.06.1
00:00.254  STATE                   Detected changed packages (marked for reinstall): {}
00:00.257  STATE                   Switch state loaded in 0.051s
00:00.257  FILE(switch-state)      Wrote /home/blond/.opam/4.06.1/.opam-switch/backup/state-20180306162455.export in 0.000s
00:00.257  COMMAND                 pin ocaml-compiler-libs to  file://<path>/v0.10.0
00:00.258  UPDATE                  updating file:///<path>/v0.10.0
00:00.258  RSYNC                   rsync: src=/<path>/v0.10.0 dst=/home/blond/.opam/4.06.1/.opam-switch/sources/ocaml-compiler-libs
[ERROR] Error getting source from file:///<path>/v0.10.0
00:00.261  SYSTEM                  rm /home/blond/.opam/4.06.1/.opam-switch/backup/state-20180306162455.export
'opam pin add --debug -n -vvv ocaml-compiler-libs v0.10.0' failed.

Where <path> is a common and regular directory just masked for this is a production code. The same problem occurs on all package whose version starts with 'v' (didn't tried with another non-digit character, though). As shown by the traces above, source pinning got somehow confused and show no version (there is a double space) and a silly url with the <path> sided with the version. Please note that <path> seems to be the current working directory.

My opam-repository clone is based on 2.0.0 branch and the corresponding opam descriptions are unchanged.

Regards.

# opam config report
# opam-version      2.0.0~rc 
# self-upgrade      no
# system            arch=x86_64 os=linux os-distribution=linuxmint os-version=18.1
# solver            builtin-mccs+glpk
# install-criteria  -removed,-count[version-lag,request],-count[version-lag,changed],-changed
# upgrade-criteria  -removed,-count[version-lag,solution],-new
# jobs              4
# repositories      1 (http), 3 (local) (default repo at 9371f757)
# pinned            0
# current-switch    4.06.1

[Ninjapouet]

I wrote a small patch that fixes the issue but i wonder if trying to detect version/path is a good idea for, as far as i know, there is no real version naming convention for ocaml packages ?