Pin a package from a specific directory of a GitHub repository

Learning
1

I’m trying to add a package that exists in a specific directory of a GitHub repository. The command I’m running (which is also the one noted in their docs) is this one:

opam pin add bril https://github.com/sampsyo/bril/tree/master/bril-ocaml

However, I get this error from that command:

[ERROR] Error getting source from https://github.com/sampsyo/bril/tree/master/bril-ocaml:
          - Unknown archive type: /private/var/folders/28/5hk42_6s4z9d5mm7cqc0jng00000gn/T/opam-59021-9b8556/bril-ocaml

I’ve resulted to pinning the package from a local copy of that repository, and that works fine, but I’m wondering what I’m missing to make the suggested command work.

Thanks for any help!

2

Most likely, opam failed to inferred that your URL should be interpreted as the address to a (remote) git repository. Either one of the following should work:

opam pin add -k git bril https://github.com/sampsyo/bril/tree/master/bril-ocaml

or

opam pin add bril https://github.com/sampsyo/bril/tree/master/bril-ocaml.git
3

I tried unpinning the local copy and then running the commands. I get the same error from both of those commands:

[ERROR] Could not synchronize ./_opam/.opam-switch/sources/bril from "git+https://github.com/sampsyo/bril/tree/master/bril-ocaml":
        "/usr/bin/git fetch -q" exited with code 128 "fatal: repository 'https://github.com/sampsyo/bril/tree/master/bril-ocaml/' not found"
[ERROR] Error getting source from git+https://github.com/sampsyo/bril/tree/master/bril-ocaml:
          - git+https://github.com/sampsyo/bril/tree/master/bril-ocaml

Perhaps I should mention that I am using a switch for this project. Thank you for the suggestion, any other ideas I could try?

4

Ah yeah, of course, the url you’ve specified is to (the github tree view of) a sub-directory, it is not a git repository in itself. I don’t know if you can opam pin it that way then…

5

Opam 2.1.0 did at one point experimentally support pinning at a subpath of a repository (with pin --subpath), but the option has since been removed.

1 Like
6

Ah! Nice to know, thank you. Then would you say the best method of doing this sort of thing is cloning and pinning from the local directory?

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7

There are a few options, depending on what workflow you plan on having with the package, but yes cloning + pinning at the right subpath with -k path should work.

Since the package builds with Dune, one alternative is to vendor it by copying the package anywhere inside your source tree (e.g. with a Git submodule in a vendors/ directory) and installing its dependencies. Dune will pick up the library automatically, and you can use (vendored_dirs <path>) to avoid accidentally running its tests / formatting its source code. This has the advantage of being somewhat easier to replicate in CI & avoiding Opam invocations if you ever want to modify the library.

1 Like
8

Great, this is very helpful! Thank you.

1 Like