go-modules: Add useVend flag to go-modules

doc/languages-frameworks/go.xml

@@ -64,6 +64,11 @@ pet = buildGoModule rec {
       <varname>subPackages</varname> limits the builder from building child packages that have not been listed. If <varname>subPackages</varname> is not specified, all child packages will be built.
      </para>
     </callout>
+    <callout arearefs='ex-buildGoModule-3'>
+     <para>
+         <varname>runVend</varname> runs the vend command to generate the vendor directory. This is useful if your code depends on c code and go mod tidy does not include the needed sources to build.
+     </para>
+    </callout>
    </calloutlist>
   </para>
 

pkgs/development/go-modules/generic/default.nix

@@ -1,4 +1,4 @@
-{ go, cacert, git, lib, removeReferencesTo, stdenv }:
+{ go, cacert, git, lib, removeReferencesTo, stdenv, vend }:
 
 { name ? "${args'.pname}-${args'.version}"
 , src
@@ -20,6 +20,9 @@
 , vendorSha256
 # Whether to delete the vendor folder supplied with the source.
 , deleteVendor ? false
+# Whether to run the vend tool to regenerate the vendor directory.
+# This is useful if any dependency contain C files.
+, runVend ? false
 
 , modSha256 ? null
 
@@ -48,6 +51,8 @@ let
 
   deleteFlag = if deleteVendor then "true" else "false";
 
+  vendCommand = if runVend then "${vend}/bin/vend" else "false";
+
   go-modules = if vendorSha256 != null then go.stdenv.mkDerivation (let modArgs = {
 
     name = "${name}-go-modules";
@@ -87,7 +92,13 @@ let
         echo "vendor folder exists, please set 'vendorSha256=null;' or 'deleteVendor=true;' in your expression"
         exit 10
       fi
-      go mod vendor
+
+      if [ ${vendCommand} != "false" ]; then
+        echo running vend to rewrite vendor folder
+        ${vendCommand}
+      else
+        go mod vendor
+      fi
       mkdir -p vendor
 
       runHook postBuild

pkgs/top-level/all-packages.nix

@@ -7419,6 +7419,8 @@ in
 
   vcstool = callPackage ../development/tools/vcstool { };
 
+  vend = callPackage ../development/tools/vend { };
+
   verilator = callPackage ../applications/science/electronics/verilator {};
 
   verilog = callPackage ../applications/science/electronics/verilog {};