Seungheonoh/npm submodule

[SeungheonOh]

Closes #1457.

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[SeungheonOh]

@aciceri @emiflake cc

[klntsky]

See comment

[SeungheonOh]

Fixed, package.json and package-lock.json can't use farmLink because how node2nix uses it.

[klntsky]

I am not sure this is the right usage of linkFarm. cp -r is still used.

[SeungheonOh]

package.json and package-lock.json are expected to be a file to be used in node2nix. Not much can be done here.

For other part, I'm not sure if it can be done without it.

[SeungheonOh]

@aciceri bump

[aciceri]

@SeungheonOh Only two perplexities:

• what happens if submodules is []? I guess you do a cp <linkFarmOut>/* . -r where <linkFarmOut> is an empty folder. If you want you could directly avoid the entire line if there are no submodules
• what happens if one wants to use a submodule which is the output of another derivation? For instance consider

submodules = [
  (pkgs.runCommand "foo-submodule" {} "mkdir -p $out/foo; magic > $out/foo")
]

The builtins.baseNameOf this derivation would be foo-submodule (I believe, haven't tested it). Is this what you want? I would make a test to check if this works.
Moreover I really don't like depending on builtins.baseNameOf, it looks flaky. But I can't give you any alternative that doesn't imply making the UI more complex:

submodules = [
 {
   name = "foo";
   path = ./foo-submodule;   
 }
 {
   name = "bar";
   path = mkBarSubmodule { inherit pkgs; src = ./bar-stuff; };   
 }
]

Said this, if it works it looks good to me, these are improvements that can be made when (and if) these problems arise.

[SeungheonOh]

Thanks for the review. I haven't consider using output of derivation as a submodule. Mainly, it was intended for subdirectories.

Because I was mainly considering subdirectories, builtins.baseNameOf was good as it gave concise and consistent paths to be imported in package.json. That being said, I'm also happy with explicit path.

[klntsky]

@SeungheonOh please implement explicit paths and avoid calling cp when submodules is [].

[emiflake]

Can this be merged? Or at least someone pick this up? We're still depending on this branch in several projects. cc: @SeungheonOh, @aciceri

[aciceri]

@klntsky In my opinion it's already mergeable.

[emiflake]

Once again bumping this PR :)
@klntsky
If it needs a rebase, or whatnot I'd be happy to help.