fix: merge InferencePool route configs during HTTPRoute merge (#3964)

pkg/ingress/kube/gateway/istio/testdata/http.status.yaml.golden

@@ -14,6 +14,22 @@ metadata:
 spec: null
 status: {}
 ---
+apiVersion: inference.networking.k8s.io/v1
+kind: InferencePool
+metadata:
+  name: infpool-model1
+  namespace: default
+spec: null
+status: {}
+---
+apiVersion: inference.networking.k8s.io/v1
+kind: InferencePool
+metadata:
+  name: infpool-model2
+  namespace: default
+spec: null
+status: {}
+---
 apiVersion: gateway.networking.k8s.io/v1beta1
 kind: GatewayClass
 metadata:
@@ -49,7 +65,7 @@ status:
     status: "True"
     type: Programmed
   listeners:
-  - attachedRoutes: 11
+  - attachedRoutes: 13
     conditions:
     - lastTransitionTime: fake
       message: No errors found
@@ -272,6 +288,54 @@ status:
 ---
 apiVersion: gateway.networking.k8s.io/v1beta1
 kind: HTTPRoute
+metadata:
+  name: multi-route-infpool-1
+  namespace: default
+spec: null
+status:
+  parents:
+  - conditions:
+    - lastTransitionTime: fake
+      message: Route was valid
+      reason: Accepted
+      status: "True"
+      type: Accepted
+    - lastTransitionTime: fake
+      message: All references resolved
+      reason: ResolvedRefs
+      status: "True"
+      type: ResolvedRefs
+    controllerName: higress.io/gateway-controller
+    parentRef:
+      name: gateway
+      namespace: higress-system
+---
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: HTTPRoute
+metadata:
+  name: multi-route-infpool-2
+  namespace: default
+spec: null
+status:
+  parents:
+  - conditions:
+    - lastTransitionTime: fake
+      message: Route was valid
+      reason: Accepted
+      status: "True"
+      type: Accepted
+    - lastTransitionTime: fake
+      message: All references resolved
+      reason: ResolvedRefs
+      status: "True"
+      type: ResolvedRefs
+    controllerName: higress.io/gateway-controller
+    parentRef:
+      name: gateway
+      namespace: higress-system
+---
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: HTTPRoute
 metadata:
   name: multiple-inferencepool-backend-refs
   namespace: default

pkg/ingress/kube/gateway/istio/testdata/http.yaml

@@ -421,3 +421,80 @@ spec:
     name: vllm-llama3-8b-instruct-epp
     port:
       number: 9002
+---
+# Test case for multiple HTTPRoutes with InferencePools on same gateway.
+# This verifies that InferencePool configs in Config.Extra are preserved when
+# the routes are merged into a single VirtualService.
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: HTTPRoute
+metadata:
+  name: multi-route-infpool-1
+  namespace: default
+spec:
+  parentRefs:
+    - name: gateway
+      namespace: higress-system
+  hostnames: ["multi-infpool.domain.example"]
+  rules:
+    - matches:
+        - path:
+            type: PathPrefix
+            value: /model1
+      backendRefs:
+        - name: infpool-model1
+          group: inference.networking.k8s.io
+          kind: InferencePool
+          port: 80
+---
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: HTTPRoute
+metadata:
+  name: multi-route-infpool-2
+  namespace: default
+spec:
+  parentRefs:
+    - name: gateway
+      namespace: higress-system
+  hostnames: ["multi-infpool.domain.example"]
+  rules:
+    - matches:
+        - path:
+            type: PathPrefix
+            value: /model2
+      backendRefs:
+        - name: infpool-model2
+          group: inference.networking.k8s.io
+          kind: InferencePool
+          port: 80
+---
+apiVersion: inference.networking.k8s.io/v1
+kind: InferencePool
+metadata:
+  name: infpool-model1
+  namespace: default
+spec:
+  targetPorts:
+    - number: 8000
+  selector:
+    matchLabels:
+      app: model1-server
+  endpointPickerRef:
+    name: model1-epp
+    port:
+      number: 9002
+---
+apiVersion: inference.networking.k8s.io/v1
+kind: InferencePool
+metadata:
+  name: infpool-model2
+  namespace: default
+spec:
+  targetPorts:
+    - number: 8000
+  selector:
+    matchLabels:
+      app: model2-server
+  endpointPickerRef:
+    name: model2-epp
+    port:
+      number: 9002

pkg/ingress/kube/gateway/istio/testdata/http.yaml.golden

@@ -242,6 +242,35 @@ spec:
 ---
 apiVersion: networking.istio.io/v1alpha3
 kind: VirtualService
+metadata:
+  annotations:
+    internal.istio.io/parents: HTTPRoute/multi-route-infpool-1.default,HTTPRoute/multi-route-infpool-2.default
+    internal.istio.io/route-semantics: gateway
+  name: higress-system~gateway-istio-autogenerated-k8s-gateway-default~multi-infpool.domain.example
+  namespace: default
+spec:
+  gateways:
+  - higress-system/gateway-istio-autogenerated-k8s-gateway-default
+  hosts:
+  - multi-infpool.domain.example
+  http:
+  - match:
+    - uri:
+        prefix: /model1
+    name: default/multi-route-infpool-1
+    route:
+    - destination:
+        host: infpool-model1-ip-aaaaf2d6.default.svc.domain.suffix
+  - match:
+    - uri:
+        prefix: /model2
+    name: default/multi-route-infpool-2
+    route:
+    - destination:
+        host: infpool-model2-ip-f857bff9.default.svc.domain.suffix
+---
+apiVersion: networking.istio.io/v1alpha3
+kind: VirtualService
 metadata:
   annotations:
     internal.istio.io/parents: HTTPRoute/redirect-prefix-replace.default