fix misleading present/absent for headers

agent/structs/config_entry_discoverychain.go

@@ -115,9 +115,8 @@ func (e *ServiceRouterConfigEntry) Validate() error {
 				if hdr.Suffix != "" {
 					hdrParts++
 				}
-				// "absent" is the bare invert=true
-				if (hdrParts == 0 && !hdr.Invert) || (hdrParts > 1) {
-					return fmt.Errorf("Route[%d] Header[%d] should only contain one of Present, Exact, Prefix, Suffix, or Regex (or just Invert)", i, j)
+				if hdrParts != 1 {
+					return fmt.Errorf("Route[%d] Header[%d] should only contain one of Present, Exact, Prefix, Suffix, or Regex", i, j)
 				}
 			}
 

agent/structs/config_entry_discoverychain_test.go

@@ -883,9 +883,9 @@ func TestServiceRouterConfigEntry(t *testing.T) {
 		{
 			name: "route with header not present",
 			entry: makerouter(routeMatch(httpMatchHeader(ServiceRouteHTTPMatchHeader{
-				Name:   "foo",
-				Invert: true,
-				//Present: false,
+				Name:    "foo",
+				Present: true,
+				Invert:  true,
 			}))),
 		},
 		{

agent/xds/routes.go

@@ -240,12 +240,6 @@ func makeRouteMatchForDiscoveryRoute(discoveryRoute *structs.DiscoveryRoute, pro
 				eh.HeaderMatchSpecifier = &envoyroute.HeaderMatcher_PresentMatch{
 					PresentMatch: true,
 				}
-			case hdr.Invert: // THIS HAS TO BE LAST
-				eh.HeaderMatchSpecifier = &envoyroute.HeaderMatcher_PresentMatch{
-					// We set this to the misleading value of 'true' here
-					// because we'll generically invert it next.
-					PresentMatch: true,
-				}
 			default:
 				continue // skip this impossible situation
 			}

agent/xds/routes_test.go

@@ -156,8 +156,9 @@ func TestRoutesFromSnapshot(t *testing.T) {
 							},
 							{
 								Match: httpMatchHeader(structs.ServiceRouteHTTPMatchHeader{
-									Name:   "x-debug",
-									Invert: true,
+									Name:    "x-debug",
+									Present: true,
+									Invert:  true,
 								}),
 								Destination: toService("hdr-not-present"),
 							},