kubernetes: patch broken go version check

fixes #35403
patch from https://github.com/kubernetes/kubernetes/pull/58207
already merged upstream - remove for next version

pkgs/applications/networking/cluster/kubernetes/default.nix

@@ -29,6 +29,11 @@ stdenv.mkDerivation rec {
 
   outputs = ["out" "man" "pause"];
 
+  # patch broken go version check, see issue #35403
+  # patch is from https://github.com/kubernetes/kubernetes/pull/58207
+  #TODO: patch already merged upstream - remove for next k8s version
+  patches = [ ./go-version-check.patch ];
+
   postPatch = ''
     substituteInPlace "hack/lib/golang.sh" --replace "_cgo" ""
     substituteInPlace "hack/generate-docs.sh" --replace "make" "make SHELL=${stdenv.shell}"

pkgs/applications/networking/cluster/kubernetes/go-version-check.patch

@@ -0,0 +1,11 @@
+--- a/hack/lib/golang.sh
++++ b/hack/lib/golang.sh
+@@ -323,7 +323,7 @@ EOF
+   go_version=($(go version))
+   local minimum_go_version
+   minimum_go_version=go1.9.1
+-  if [[ "${go_version[2]}" < "${minimum_go_version}" && "${go_version[2]}" != "devel" ]]; then
++  if [[ "${minimum_go_version}" != $(echo -e "${minimum_go_version}\n${go_version[2]}" | sort -s -t. -k 1,1 -k 2,2n -k 3,3n | head -n1) && "${go_version[2]}" != "devel" ]]; then
+     kube::log::usage_from_stdin <<EOF
+ Detected go version: ${go_version[*]}.
+ Kubernetes requires ${minimum_go_version} or greater.