fixes: fix mount removal in adjustments, add a test case for it.

pkg/adaptation/adaptation_suite_test.go

@@ -455,6 +455,9 @@ var _ = Describe("Plugin container creation adjustments", func() {
 			}
 			a.AddMount(mnt)
 
+		case "remove mount":
+			a.RemoveMount("/remove/test/destination")
+
 		case "environment":
 			if overwrite {
 				a.RemoveEnv("key")
@@ -560,6 +563,13 @@ var _ = Describe("Plugin container creation adjustments", func() {
 						PodSandboxId: "pod0",
 						Name:         "ctr0",
 						State:        api.ContainerState_CONTAINER_CREATED, // XXX FIXME-kludge
+						Mounts: []*api.Mount{
+							{
+								Type:        "bind",
+								Source:      "/remove/test",
+								Destination: "/remove/test/destination",
+							},
+						},
 					}
 				)
 
@@ -599,6 +609,15 @@ var _ = Describe("Plugin container creation adjustments", func() {
 					},
 				},
 			),
+			Entry("remove a mount", "remove mount",
+				&api.ContainerAdjustment{
+					Mounts: []*api.Mount{
+						{
+							Destination: api.MarkForRemoval("/remove/test/destination"),
+						},
+					},
+				},
+			),
 			Entry("adjust environment", "environment",
 				&api.ContainerAdjustment{
 					Env: []*api.KeyValue{

pkg/adaptation/result.go

@@ -331,6 +331,13 @@ func (r *result) adjustMounts(mounts []*Mount, plugin string) error {
 		r.reply.adjust.Mounts = append(r.reply.adjust.Mounts, m)
 	}
 
+	// next, apply deletions with no corresponding additions
+	for _, m := range del {
+		if _, ok := mod[api.ClearRemovalMarker(m.Destination)]; !ok {
+			r.reply.adjust.Mounts = append(r.reply.adjust.Mounts, m)
+		}
+	}
+
 	// finally, apply additions/modifications to plugin container creation request
 	create.Container.Mounts = append(create.Container.Mounts, add...)
 

pkg/api/helpers.go

@@ -57,3 +57,14 @@ func IsMarkedForRemoval(key string) (string, bool) {
 func MarkForRemoval(key string) string {
 	return "-" + key
 }
+
+// ClearRemovalMarker returns a key cleared from any removal marker.
+func ClearRemovalMarker(key string) string {
+	if key == "" {
+		return ""
+	}
+	if key[0] == '-' {
+		return key[1:]
+	}
+	return key
+}