Dear OCaml Users,

I had to patch core to make it compile on cygwin and run into issues with opam's version selection mechanism with the patched and pinned core version. The root cause is that the opam file in

https://ocaml.janestreet.com/ocaml-core/113.33/files/core-113.33.03.tar.gz

which I used as source for my patch, and in my local opam repo (opam installed from scratch in fresh cygwin today):

D:\bin\cygwin_opam_64_test6\home\soegtrop\.opam\repo\default\packages\core\core.113.33.03

are different. The file in my local repo contains explicit version numbers for the dependencies, e.g.

  "bin_prot"        {>= "113.33.03" & < "113.34.00"}

while the version on git and in the tgz file doesn't, e.g.:

  "bin_prot"

This has the effect that opam tries to install the dependencies for core 113.33.03 with version 113.24.0, which doesn't work.

I wonder where opam gets the opam files for core from and why they are different. Does opam somehow modify the opam files in the local repository?

I use these commands to install the patched version of core:

    <download and unpack core into core-113.33.03>
    cd core-113.33.03
    patch -p1 -i ../core-113.33.03.patch
    opam pin add core . -n
   cd ..
    opam install core

Best regards,

Michael
Intel Deutschland GmbH
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