buildDotnetModule: allow passing derivations to nugetDeps

Sometimes I want to pass a different implementation of `mkNugetDeps`.
For example in private repos, it can be handy to use `__noChroot = true`
and bypass the deps.nix generation altogether. Or some Nuget packages
ship with ELF binaries that need to be patched, and that's best done as
soon as possible.

2 files changed, 4 insertions, 2 deletions

diff --git a/doc/languages-frameworks/dotnet.section.md b/doc/languages-frameworks/dotnet.section.md
index f7af28a1677..408446674e9 100644
--- a/doc/languages-frameworks/dotnet.section.md
+++ b/doc/languages-frameworks/dotnet.section.md
@@ -72,7 +72,7 @@ The `dotnetCorePackages.sdk` contains both a runtime and the full sdk of a given
 To package Dotnet applications, you can use `buildDotnetModule`. This has similar arguments to `stdenv.mkDerivation`, with the following additions:
 
 * `projectFile` has to be used for specifying the dotnet project file relative to the source root. These usually have `.sln` or `.csproj` file extensions. This can be an array of multiple projects as well.
-* `nugetDeps` has to be used to specify the NuGet dependency file. Unfortunately, these cannot be deterministically fetched without a lockfile. A script to fetch these is available as `passthru.fetch-deps`. This file can also be generated manually using `nuget-to-nix` tool, which is available in nixpkgs.
+* `nugetDeps` takes either a path to a `deps.nix` file, or a derivation. The `deps.nix` file can be generated using the script attached to `passthru.fetch-deps`. This file can also be generated manually using `nuget-to-nix` tool, which is available in nixpkgs. If the argument is a derivation, it will be used directly and assume it has the same output as `mkNugetDeps`.
 * `packNupkg` is used to pack project as a `nupkg`, and installs it to `$out/share`. If set to `true`, the derivation can be used as a dependency for another dotnet project by adding it to `projectReferences`.
 * `projectReferences` can be used to resolve `ProjectReference` project items. Referenced projects can be packed with `buildDotnetModule` by setting the `packNupkg = true` attribute and passing a list of derivations to `projectReferences`. Since we are sharing referenced projects as NuGets they must be added to csproj/fsproj files as `PackageReference` as well.
  For example, your project has a local dependency:
diff --git a/pkgs/build-support/dotnet/build-dotnet-module/default.nix b/pkgs/build-support/dotnet/build-dotnet-module/default.nix
index fa987237a75..96e7596ed62 100644
--- a/pkgs/build-support/dotnet/build-dotnet-module/default.nix
+++ b/pkgs/build-support/dotnet/build-dotnet-module/default.nix
@@ -78,7 +78,9 @@ let
     then linkFarmFromDrvs "${name}-project-references" projectReferences
     else null;
 
-  _nugetDeps = mkNugetDeps { inherit name; nugetDeps = import nugetDeps; };
+  _nugetDeps = if lib.isDerivation nugetDeps
+    then nugetDeps
+    else mkNugetDeps { inherit name; nugetDeps = import nugetDeps; };
 
   nuget-source = mkNugetSource {
     name = "${name}-nuget-source";