fix: Health status for HTTPRoute with multiple generations (#24958) (#24959)

Signed-off-by: Alexander Lindeskär <lindeskar@users.noreply.github.com>

resource_customizations/gateway.networking.k8s.io/HTTPRoute/health.lua

@@ -9,10 +9,39 @@ function checkConditions(conditions, conditionType)
   return true
 end
 
+-- isParentGenerationObserved checks if a parent's conditions match the current resource generation
+-- For HTTPRoute, observedGeneration is stored in each condition within a parent
+function isParentGenerationObserved(obj, parent)
+  if obj.metadata.generation == nil then
+    -- If no generation is set, accept all conditions
+    return true
+  end
+
+  if parent.conditions == nil or #parent.conditions == 0 then
+    return false
+  end
+
+  -- Check if all conditions have observedGeneration matching current generation
+  for _, condition in ipairs(parent.conditions) do
+    if condition.observedGeneration ~= nil then
+      if condition.observedGeneration ~= obj.metadata.generation then
+        return false
+      end
+    end
+  end
+
+  return true
+end
+
 if obj.status ~= nil then
   if obj.status.parents ~= nil then
     for _, parent in ipairs(obj.status.parents) do
       if parent.conditions ~= nil then
+        -- Skip this parent if it's not from the current generation
+        if not isParentGenerationObserved(obj, parent) then
+          goto continue
+        end
+
         local resolvedRefsFalse, resolvedRefsMsg = checkConditions(parent.conditions, "ResolvedRefs")
         local acceptedFalse, acceptedMsg = checkConditions(parent.conditions, "Accepted")
 
@@ -44,15 +73,20 @@ if obj.status ~= nil then
           hs.message = "Parent " .. (parent.parentRef.name or "") .. ": " .. progressingMsg
           return hs
         end
+
+        ::continue::
       end
     end
 
     if #obj.status.parents > 0 then
       for _, parent in ipairs(obj.status.parents) do
         if parent.conditions ~= nil and #parent.conditions > 0 then
-          hs.status = "Healthy"
-          hs.message = "HTTPRoute is healthy"
-          return hs
+          -- Only mark as healthy if we found a parent from the current generation
+          if isParentGenerationObserved(obj, parent) then
+            hs.status = "Healthy"
+            hs.message = "HTTPRoute is healthy"
+            return hs
+          end
         end
       end
     end

resource_customizations/gateway.networking.k8s.io/HTTPRoute/health_test.yaml

@@ -14,4 +14,8 @@ tests:
 - healthStatus:
     status: Progressing
     message: "Parent example-gateway: Route is still being programmed"
-  inputPath: testdata/progressing.yaml
+  inputPath: testdata/progressing.yaml
+- healthStatus:
+    status: Healthy
+    message: HTTPRoute is healthy
+  inputPath: testdata/healthy_multiple_generations.yaml

resource_customizations/gateway.networking.k8s.io/HTTPRoute/testdata/healthy_multiple_generations.yaml

@@ -0,0 +1,59 @@
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: example-httproute
+  generation: 2
+spec:
+  parentRefs:
+    - kind: Gateway
+      name: eg
+      namespace: envoy-gateway-system
+      sectionName: foo-nonexistent
+  hostnames:
+    - "example-httproute.example.com"
+  rules:
+    - backendRefs:
+        - name: example-service
+          port: 8080
+status:
+  parents:
+    - conditions:
+        - lastTransitionTime: "2025-10-14T11:19:41Z"
+          message: No listeners match this parent ref
+          observedGeneration: 1
+          reason: NoMatchingParent
+          status: "False"
+          type: Accepted
+        - lastTransitionTime: "2025-10-14T11:19:41Z"
+          message: Resolved all the Object references for the Route
+          observedGeneration: 1
+          reason: ResolvedRefs
+          status: "True"
+          type: ResolvedRefs
+      controllerName: gateway.envoyproxy.io/gatewayclass-controller
+      parentRef:
+        group: gateway.networking.k8s.io
+        kind: Gateway
+        name: eg
+        namespace: envoy-gateway-system
+        sectionName: foo-nonexistent
+    - conditions:
+        - lastTransitionTime: "2025-10-14T11:25:18Z"
+          message: Route is accepted
+          observedGeneration: 2
+          reason: Accepted
+          status: "True"
+          type: Accepted
+        - lastTransitionTime: "2025-10-14T11:25:18Z"
+          message: Resolved all the Object references for the Route
+          observedGeneration: 2
+          reason: ResolvedRefs
+          status: "True"
+          type: ResolvedRefs
+      controllerName: gateway.envoyproxy.io/gatewayclass-controller
+      parentRef:
+        group: gateway.networking.k8s.io
+        kind: Gateway
+        name: eg
+        namespace: envoy-gateway-system
+        sectionName: https-net