From 8698c2a7d5096144f14680704c4fba707e196518 Mon Sep 17 00:00:00 2001
From: John Children <32305209+johnchildren@users.noreply.github.com>
Date: Fri, 24 May 2019 17:10:35 +0100
Subject: [PATCH] buildGoModule: pre-initialize module cache (#61967)

For some Go projects a go.mod file is included but there are no listed
dependencies. When this is encountered the Go toolchain will not create
a cache folder for downloaded dependencies which causes buildGoModule to
fail.

An example of a project like this that is widely used is:
https://github.com/golang/protobuf

This commit adds a mkdir command to ensure that the directory always
exists so it can be copied and prevent the failure.
---
 pkgs/development/go-modules/generic/default.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pkgs/development/go-modules/generic/default.nix b/pkgs/development/go-modules/generic/default.nix
index fed0234b46c..ca1bab1e087 100644
--- a/pkgs/development/go-modules/generic/default.nix
+++ b/pkgs/development/go-modules/generic/default.nix
@@ -54,6 +54,7 @@ let
 
       export GOCACHE=$TMPDIR/go-cache
       export GOPATH="$TMPDIR/go"
+      mkdir -p "''${GOPATH}/pkg/mod/cache/download"
 
       runHook postConfigure
     '';