update kube and vendor dependencies

With kubernetes 1.18 release of client-go, signatures on methods in
generated clientsets, dynamic, metadata, and scale clients have been
modified to accept context.Context as a first argument.
Signatures of Create, Update, and Patch methods have been updated
to accept CreateOptions, UpdateOptions and PatchOptions respectively.
Signatures of Delete and DeleteCollection methods now accept
DeleteOptions by value instead of by reference.
These changes are now accommodated with this PR and client-go
and dependencies are updated to v1.18.0

Signed-off-by: Humble Chirammal <hchiramm@redhat.com>

vendor/k8s.io/code-generator/cmd/go-to-protobuf/protobuf/cmd.go

@@ -29,9 +29,6 @@ import (
 	"strings"
 
 	flag "github.com/spf13/pflag"
-	"gonum.org/v1/gonum/graph"
-	"gonum.org/v1/gonum/graph/simple"
-	"gonum.org/v1/gonum/graph/topo"
 
 	"k8s.io/code-generator/pkg/util"
 	"k8s.io/gengo/args"
@@ -374,38 +371,73 @@ func deps(c *generator.Context, pkgs []*protobufPackage) map[string][]string {
 	return ret
 }
 
+// given a set of pkg->[]deps, return the order that ensures all deps are processed before the things that depend on them
 func importOrder(deps map[string][]string) ([]string, error) {
-	nodes := map[string]graph.Node{}
-	names := map[int64]string{}
-	g := simple.NewDirectedGraph()
-	for pkg, imports := range deps {
-		for _, imp := range imports {
-			if _, found := nodes[pkg]; !found {
-				n := g.NewNode()
-				g.AddNode(n)
-				nodes[pkg] = n
-				names[n.ID()] = pkg
-			}
-			if _, found := nodes[imp]; !found {
-				n := g.NewNode()
-				g.AddNode(n)
-				nodes[imp] = n
-				names[n.ID()] = imp
-			}
-			g.SetEdge(g.NewEdge(nodes[imp], nodes[pkg]))
+	// add all nodes and edges
+	var remainingNodes = map[string]struct{}{}
+	var graph = map[edge]struct{}{}
+	for to, froms := range deps {
+		remainingNodes[to] = struct{}{}
+		for _, from := range froms {
+			remainingNodes[from] = struct{}{}
+			graph[edge{from: from, to: to}] = struct{}{}
 		}
 	}
 
-	ret := []string{}
-	sorted, err := topo.Sort(g)
-	if err != nil {
-		return nil, err
+	// find initial nodes without any dependencies
+	sorted := findAndRemoveNodesWithoutDependencies(remainingNodes, graph)
+	for i := 0; i < len(sorted); i++ {
+		node := sorted[i]
+		removeEdgesFrom(node, graph)
+		sorted = append(sorted, findAndRemoveNodesWithoutDependencies(remainingNodes, graph)...)
+	}
+	if len(remainingNodes) > 0 {
+		return nil, fmt.Errorf("cycle: remaining nodes: %#v, remaining edges: %#v", remainingNodes, graph)
 	}
 	for _, n := range sorted {
-		ret = append(ret, names[n.ID()])
-		fmt.Println("topological order", names[n.ID()])
+		fmt.Println("topological order", n)
+	}
+	return sorted, nil
+}
+
+// edge describes a from->to relationship in a graph
+type edge struct {
+	from string
+	to   string
+}
+
+// findAndRemoveNodesWithoutDependencies finds nodes in the given set which are not pointed to by any edges in the graph,
+// removes them from the set of nodes, and returns them in sorted order
+func findAndRemoveNodesWithoutDependencies(nodes map[string]struct{}, graph map[edge]struct{}) []string {
+	roots := []string{}
+	// iterate over all nodes as potential "to" nodes
+	for node := range nodes {
+		incoming := false
+		// iterate over all remaining edges
+		for edge := range graph {
+			// if there's any edge to the node we care about, it's not a root
+			if edge.to == node {
+				incoming = true
+				break
+			}
+		}
+		// if there are no incoming edges, remove from the set of remaining nodes and add to our results
+		if !incoming {
+			delete(nodes, node)
+			roots = append(roots, node)
+		}
+	}
+	sort.Strings(roots)
+	return roots
+}
+
+// removeEdgesFrom removes any edges from the graph where edge.from == node
+func removeEdgesFrom(node string, graph map[edge]struct{}) {
+	for edge := range graph {
+		if edge.from == node {
+			delete(graph, edge)
+		}
 	}
-	return ret, nil
 }
 
 type positionOrder struct {