UPSTREAM: <carry>: kcp modifications

Signed-off-by: Dr. Stefan Schimanski <[email protected]>

.prow.yaml

@@ -0,0 +1,13 @@
+presubmits:
+  - name: pull-controller-runtime-everything
+    always_run: true
+    decorate: true
+    clone_uri: "ssh://[email protected]/kcp-dev/controller-runtime.git"
+    labels:
+      preset-goproxy: "true"
+    spec:
+      containers:
+      - image: ghcr.io/kcp-dev/infra/build:1.22.2-1
+        command:
+        - make
+        - test

DOWNSTREAM_OWNERS

@@ -0,0 +1,5 @@
+approvers:
+  - sttts
+  - xrstf
+  - mjudeikis
+  - embik

go.mod

@@ -3,6 +3,7 @@ module sigs.k8s.io/controller-runtime
 go 1.22.0
 
 require (
+	github.com/evanphx/json-patch v5.6.0+incompatible // Using v4 to match upstream
 	github.com/evanphx/json-patch/v5 v5.9.0
 	github.com/fsnotify/fsnotify v1.7.0
 	github.com/go-logr/logr v1.4.2

go.sum

@@ -1,7 +1,7 @@
-github.com/antlr4-go/antlr/v4 v4.13.0 h1:lxCg3LAv+EUK6t1i0y1V6/SLeUi0eKEKdhQAlS8TVTI=
-github.com/antlr4-go/antlr/v4 v4.13.0/go.mod h1:pfChB/xh/Unjila75QW7+VU4TSnWnnk9UTnmpPaOR2g=
-github.com/asaskevich/govalidator v0.0.0-20190424111038-f61b66f89f4a h1:idn718Q4B6AGu/h5Sxe66HYVdqdGu2l9Iebqhi/AEoA=
-github.com/asaskevich/govalidator v0.0.0-20190424111038-f61b66f89f4a/go.mod h1:lB+ZfQJz7igIIfQNfa7Ml4HSf2uFQQRzpGGRXenZAgY=
+github.com/antlr/antlr4/runtime/Go/antlr/v4 v4.0.0-20230305170008-8188dc5388df h1:7RFfzj4SSt6nnvCPbCqijJi1nWCd+TqAT3bYCStRC18=
+github.com/antlr/antlr4/runtime/Go/antlr/v4 v4.0.0-20230305170008-8188dc5388df/go.mod h1:pSwJ0fSY5KhvocuWSx4fz3BA8OrA1bQn+K1Eli3BRwM=
+github.com/asaskevich/govalidator v0.0.0-20230301143203-a9d515a09cc2 h1:DklsrG3dyBCFEj5IhUbnKptjxatkF07cF2ak3yi77so=
+github.com/asaskevich/govalidator v0.0.0-20230301143203-a9d515a09cc2/go.mod h1:WaHUgvxTVq04UNunO+XhnAqY/wQc+bxr74GqbsZ/Jqw=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/blang/semver/v4 v4.0.0 h1:1PFHFE6yCCTv8C1TeyNNarDzntLi7wMI5i/pzqYIsAM=
@@ -18,8 +18,8 @@ github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/emicklei/go-restful/v3 v3.11.0 h1:rAQeMHw1c7zTmncogyy8VvRZwtkmkZ4FxERmMY4rD+g=
 github.com/emicklei/go-restful/v3 v3.11.0/go.mod h1:6n3XBCmQQb25CM2LCACGz8ukIrRry+4bhvbpWn3mrbc=
-github.com/evanphx/json-patch v0.5.2 h1:xVCHIVMUu1wtM/VkR9jVZ45N3FhZfYMMYGorLCR8P3k=
-github.com/evanphx/json-patch v0.5.2/go.mod h1:ZWS5hhDbVDyob71nXKNL0+PWn6ToqBHMikGIFbs31qQ=
+github.com/evanphx/json-patch v5.6.0+incompatible h1:jBYDEEiFBPxA0v50tFdvOzQQTCvpL6mnFh5mB2/l16U=
+github.com/evanphx/json-patch v5.6.0+incompatible/go.mod h1:50XU6AFN0ol/bzJsmQLiYLvXMP4fmwYFNcr97nuDLSk=
 github.com/evanphx/json-patch/v5 v5.9.0 h1:kcBlZQbplgElYIlo/n1hJbls2z/1awpXxpRi0/FOJfg=
 github.com/evanphx/json-patch/v5 v5.9.0/go.mod h1:VNkHZ/282BpEyt/tObQO8s5CMPmYYq14uClGH4abBuQ=
 github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
@@ -46,8 +46,11 @@ github.com/go-task/slim-sprig/v3 v3.0.0 h1:sUs3vkvUymDpBKi3qH1YSqBQk9+9D/8M2mN1v
 github.com/go-task/slim-sprig/v3 v3.0.0/go.mod h1:W848ghGpv3Qj3dhTPRyJypKRiqCdHZiAzKg9hl15HA8=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
+github.com/golang/glog v1.1.2 h1:DVjP2PbBOzHyzA+dn3WhHIq4NdVu3Q+pvivFICf/7fo=
+github.com/golang/glog v1.1.2/go.mod h1:zR+okUeTbrL6EL3xHUDxZuEtGv04p5shwip1+mL/rLQ=
 github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da h1:oI5xCqsCo564l8iNU+DwB5epxmsaqB+rhGL0m5jtYqE=
 github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
+github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
 github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
 github.com/google/cel-go v0.20.1 h1:nDx9r8S3L4pE61eDdt8igGj8rf5kjYR3ILxWIpWNi84=
@@ -60,20 +63,27 @@ github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeN
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/gofuzz v1.2.0 h1:xRy4A+RhZaiKjJ1bPfwQ8sedCA+YS2YcCHW6ec7JMi0=
 github.com/google/gofuzz v1.2.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
-github.com/google/pprof v0.0.0-20240525223248-4bfdf5a9a2af h1:kmjWCqn2qkEml422C2Rrd27c3VGxi6a/6HNq8QmHRKM=
-github.com/google/pprof v0.0.0-20240525223248-4bfdf5a9a2af/go.mod h1:K1liHPHnj73Fdn/EKuT8nrFqBihUSKXoLYU0BuatOYo=
-github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
-github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/grpc-ecosystem/grpc-gateway/v2 v2.20.0 h1:bkypFPDjIYGfCYD5mRBvpqxfYX1YCS1PXdKYWi8FsN0=
-github.com/grpc-ecosystem/grpc-gateway/v2 v2.20.0/go.mod h1:P+Lt/0by1T8bfcF3z737NnSbmxQAppXMRziHUxPOC8k=
-github.com/imdario/mergo v0.3.6 h1:xTNEAn+kxVO7dTZGu0CegyqKZmoWFI0rF8UxjlB2d28=
-github.com/imdario/mergo v0.3.6/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
-github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
-github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1 h1:K6RDEckDVWvDI9JAJYCmNdQXq6neHJOYx3V6jnqNEec=
+github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
+github.com/google/uuid v1.3.1 h1:KjJaJ9iWZ3jOFZIf1Lqf4laDRCasjl0BCmnEGxkdLb4=
+github.com/google/uuid v1.3.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/grpc-ecosystem/grpc-gateway/v2 v2.16.0 h1:YBftPWNWd4WwGqtY2yeZL2ef8rHAxPBD8KFhJpmcqms=
+github.com/grpc-ecosystem/grpc-gateway/v2 v2.16.0/go.mod h1:YN5jB8ie0yfIUg6VvR9Kz84aCaG7AsGZnLjhHbUqwPg=
+github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
+github.com/imdario/mergo v0.3.13 h1:lFzP57bqS/wsqKssCGmtLAb8A0wKjLGrve2q3PPVcBk=
+github.com/imdario/mergo v0.3.13/go.mod h1:4lJ1jqUDcsbIECGy0RUJAXNIhg+6ocWgb1ALK2O4oXg=
 github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
 github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
+github.com/kcp-dev/apimachinery/v2 v2.0.0-alpha.0.0.20230926071920-57d168bcbe34 h1:tom0JX5OmAeOOmkGv8LaYHDtA1xAKDiQL5U0vhYYgdM=
+github.com/kcp-dev/apimachinery/v2 v2.0.0-alpha.0.0.20230926071920-57d168bcbe34/go.mod h1:cWoaYGHl1nlzdEM2xvMzIASkEZJZLSf5nhe17M7wDhw=
+github.com/kcp-dev/controller-runtime/examples/kcp v0.0.0-20240429114249-607a854c2cfe h1:blMRNjSiWkdZHQeU4B0WraZVVVniDklkUSdom7FWlxU=
+github.com/kcp-dev/controller-runtime/examples/kcp v0.0.0-20240429114249-607a854c2cfe/go.mod h1:J5yVL/5SPHDegVbEV9k7K/WpjVFvQUZMt/KB+sPR0V0=
+github.com/kcp-dev/kcp/sdk v0.24.0 h1:ZTfStDOQshVU2cnrqjgMo9xb0VNblkmrgMRtl0PCQEY=
+github.com/kcp-dev/kcp/sdk v0.24.0/go.mod h1:Pd2xxw/qhgfF2xgHolVwheq9VOJwPtNrBmxgBlYmjfk=
+github.com/kcp-dev/logicalcluster/v3 v3.0.5 h1:JbYakokb+5Uinz09oTXomSUJVQsqfxEvU4RyHUYxHOU=
+github.com/kcp-dev/logicalcluster/v3 v3.0.5/go.mod h1:EWBUBxdr49fUB1cLMO4nOdBWmYifLbP1LfoL20KkXYY=
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
@@ -122,7 +132,7 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
@@ -216,11 +226,11 @@ gopkg.in/evanphx/json-patch.v4 v4.12.0 h1:n6jtcsulIzXPJaxegRbvFNNrZDjbij7ny3gmSP
 gopkg.in/evanphx/json-patch.v4 v4.12.0/go.mod h1:p8EYWUEYMpynmqDbY58zCKCFZw8pRWMG4EsWvDvM72M=
 gopkg.in/inf.v0 v0.9.1 h1:73M5CoZyi3ZLMOyDlQh031Cx6N9NDJ2Vvfl76EDAgDc=
 gopkg.in/inf.v0 v0.9.1/go.mod h1:cWUDdTG/fYaXco+Dcufb5Vnc6Gp2YChqWtbxRZE0mXw=
-gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.0/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 k8s.io/api v0.31.0 h1:b9LiSjR2ym/SzTOlfMHm1tr7/21aD7fSkqgD/CVJBCo=

pkg/cache/cache.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"net/http"
 	"sort"
+	"strings"
 	"time"
 
 	"golang.org/x/exp/maps"
@@ -169,6 +170,14 @@ type Options struct {
 	// instead of `reconcile.Result{}`.
 	SyncPeriod *time.Duration
 
+	// NewInformerFunc is a function that is used to create SharedIndexInformers.
+	// Defaults to cache.NewSharedIndexInformer from client-go
+	NewInformerFunc client.NewInformerFunc
+
+	// Indexers is the indexers that the informers will be configured to use.
+	// Will always have the standard NamespaceIndex.
+	Indexers toolscache.Indexers
+
 	// ReaderFailOnMissingInformer configures the cache to return a ErrResourceNotCached error when a user
 	// requests, using Get() and List(), a resource the cache does not already have an informer for.
 	//
@@ -225,9 +234,6 @@ type Options struct {
 	// ByObject restricts the cache's ListWatch to the desired fields per GVK at the specified object.
 	// If unset, this will fall through to the Default* settings.
 	ByObject map[client.Object]ByObject
-
-	// newInformer allows overriding of NewSharedIndexInformer for testing.
-	newInformer *func(toolscache.ListerWatcher, runtime.Object, time.Duration, toolscache.Indexers) toolscache.SharedIndexInformer
 }
 
 // ByObject offers more fine-grained control over the cache's ListWatch by object.
@@ -398,9 +404,10 @@ func newCache(restConfig *rest.Config, opts Options) newCacheFunc {
 				Transform:             config.Transform,
 				WatchErrorHandler:     opts.DefaultWatchErrorHandler,
 				UnsafeDisableDeepCopy: ptr.Deref(config.UnsafeDisableDeepCopy, false),
-				NewInformer:           opts.newInformer,
+				NewInformer:           opts.NewInformerFunc,
 			}),
 			readerFailOnMissingInformer: opts.ReaderFailOnMissingInformer,
+			clusterIndexes:              strings.HasSuffix(restConfig.Host, "/clusters/*"),
 		}
 	}
 }
@@ -507,6 +514,10 @@ func defaultOpts(config *rest.Config, opts Options) (Options, error) {
 	if opts.SyncPeriod == nil {
 		opts.SyncPeriod = &defaultSyncPeriod
 	}
+
+	if opts.NewInformerFunc == nil {
+		opts.NewInformerFunc = toolscache.NewSharedIndexInformer
+	}
 	return opts, nil
 }
 

pkg/cache/cache_test.go

@@ -544,14 +544,9 @@ func NonBlockingGetTest(createCacheFunc func(config *rest.Config, opts cache.Opt
 			Expect(err).NotTo(HaveOccurred())
 
 			By("creating the informer cache")
-			v := reflect.ValueOf(&opts).Elem()
-			newInformerField := v.FieldByName("newInformer")
-			newFakeInformer := func(_ kcache.ListerWatcher, _ runtime.Object, _ time.Duration, _ kcache.Indexers) kcache.SharedIndexInformer {
+			opts.NewInformerFunc = func(_ kcache.ListerWatcher, _ runtime.Object, _ time.Duration, _ kcache.Indexers) kcache.SharedIndexInformer {
 				return &controllertest.FakeInformer{Synced: false}
 			}
-			reflect.NewAt(newInformerField.Type(), newInformerField.Addr().UnsafePointer()).
-				Elem().
-				Set(reflect.ValueOf(&newFakeInformer))
 			informerCache, err = createCacheFunc(cfg, opts)
 			Expect(err).NotTo(HaveOccurred())
 			By("running the cache and waiting for it to sync")

pkg/cache/defaulting_test.go

@@ -401,6 +401,9 @@ func TestDefaultOpts(t *testing.T) {
 				t.Fatal(err)
 			}
 
+			// We cannot reference kcp.NewInformerWithClusterIndexes due to import cycle.
+			defaulted.NewInformerFunc = nil
+
 			if diff := tc.verification(defaulted); diff != "" {
 				t.Errorf("expected config differs from actual: %s", diff)
 			}

pkg/cache/informer_cache.go

@@ -31,6 +31,8 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/cache/internal"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
+
+	"github.com/kcp-dev/logicalcluster/v3"
 )
 
 var (
@@ -68,6 +70,7 @@ type informerCache struct {
 	scheme *runtime.Scheme
 	*internal.Informers
 	readerFailOnMissingInformer bool
+	clusterIndexes              bool
 }
 
 // Get implements Reader.
@@ -217,10 +220,10 @@ func (ic *informerCache) IndexField(ctx context.Context, obj client.Object, fiel
 	if err != nil {
 		return err
 	}
-	return indexByField(informer, field, extractValue)
+	return indexByField(informer, field, extractValue, ic.clusterIndexes)
 }
 
-func indexByField(informer Informer, field string, extractValue client.IndexerFunc) error {
+func indexByField(informer Informer, field string, extractValue client.IndexerFunc, clusterIndexes bool) error {
 	indexFunc := func(objRaw interface{}) ([]string, error) {
 		// TODO(directxman12): check if this is the correct type?
 		obj, isObj := objRaw.(client.Object)
@@ -233,6 +236,13 @@ func indexByField(informer Informer, field string, extractValue client.IndexerFu
 		}
 		ns := meta.GetNamespace()
 
+		keyFunc := internal.KeyToNamespacedKey
+		if clusterName := logicalcluster.From(obj); clusterIndexes && !clusterName.Empty() {
+			keyFunc = func(ns, val string) string {
+				return internal.KeyToClusteredKey(clusterName.String(), ns, val)
+			}
+		}
+
 		rawVals := extractValue(obj)
 		var vals []string
 		if ns == "" {
@@ -242,14 +252,15 @@ func indexByField(informer Informer, field string, extractValue client.IndexerFu
 			// if we need to add non-namespaced versions too, double the length
 			vals = make([]string, len(rawVals)*2)
 		}
+
 		for i, rawVal := range rawVals {
 			// save a namespaced variant, so that we can ask
 			// "what are all the object matching a given index *in a given namespace*"
-			vals[i] = internal.KeyToNamespacedKey(ns, rawVal)
+			vals[i] = keyFunc(ns, rawVal)
 			if ns != "" {
 				// if we have a namespace, also inject a special index key for listing
 				// regardless of the object namespace
-				vals[i+len(rawVals)] = internal.KeyToNamespacedKey("", rawVal)
+				vals[i+len(rawVals)] = keyFunc("", rawVal)
 			}
 		}
 

pkg/cache/internal/cache_reader.go

@@ -21,6 +21,9 @@ import (
 	"fmt"
 	"reflect"
 
+	kcpcache "github.com/kcp-dev/apimachinery/v2/pkg/cache"
+	"github.com/kcp-dev/logicalcluster/v3"
+
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	apimeta "k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/fields"
@@ -31,6 +34,7 @@ import (
 
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/internal/field/selector"
+	"sigs.k8s.io/controller-runtime/pkg/kontext"
 )
 
 // CacheReader is a client.Reader.
@@ -54,12 +58,22 @@ type CacheReader struct {
 }
 
 // Get checks the indexer for the object and writes a copy of it if found.
-func (c *CacheReader) Get(_ context.Context, key client.ObjectKey, out client.Object, _ ...client.GetOption) error {
+func (c *CacheReader) Get(ctx context.Context, key client.ObjectKey, out client.Object, _ ...client.GetOption) error {
 	if c.scopeName == apimeta.RESTScopeNameRoot {
 		key.Namespace = ""
 	}
 	storeKey := objectKeyToStoreKey(key)
 
+	// create cluster-aware key for KCP
+	_, isClusterAware := c.indexer.GetIndexers()[kcpcache.ClusterAndNamespaceIndexName]
+	clusterName, _ := kontext.ClusterFrom(ctx)
+	if isClusterAware && clusterName.Empty() {
+		return fmt.Errorf("cluster-aware cache requires a cluster in context")
+	}
+	if isClusterAware {
+		storeKey = clusterName.String() + "|" + storeKey
+	}
+
 	// Lookup the object from the indexer cache
 	obj, exists, err := c.indexer.GetByKey(storeKey)
 	if err != nil {
@@ -105,7 +119,7 @@ func (c *CacheReader) Get(_ context.Context, key client.ObjectKey, out client.Ob
 }
 
 // List lists items out of the indexer and writes them to out.
-func (c *CacheReader) List(_ context.Context, out client.ObjectList, opts ...client.ListOption) error {
+func (c *CacheReader) List(ctx context.Context, out client.ObjectList, opts ...client.ListOption) error {
 	var objs []interface{}
 	var err error
 
@@ -116,6 +130,9 @@ func (c *CacheReader) List(_ context.Context, out client.ObjectList, opts ...cli
 		return fmt.Errorf("continue list option is not supported by the cache")
 	}
 
+	_, isClusterAware := c.indexer.GetIndexers()[kcpcache.ClusterAndNamespaceIndexName]
+	clusterName, _ := kontext.ClusterFrom(ctx)
+
 	switch {
 	case listOpts.FieldSelector != nil:
 		requiresExact := selector.RequiresExactMatch(listOpts.FieldSelector)
@@ -125,11 +142,19 @@ func (c *CacheReader) List(_ context.Context, out client.ObjectList, opts ...cli
 		// list all objects by the field selector. If this is namespaced and we have one, ask for the
 		// namespaced index key. Otherwise, ask for the non-namespaced variant by using the fake "all namespaces"
 		// namespace.
-		objs, err = byIndexes(c.indexer, listOpts.FieldSelector.Requirements(), listOpts.Namespace)
+		objs, err = byIndexes(c.indexer, listOpts.FieldSelector.Requirements(), clusterName, listOpts.Namespace)
 	case listOpts.Namespace != "":
-		objs, err = c.indexer.ByIndex(cache.NamespaceIndex, listOpts.Namespace)
+		if isClusterAware && !clusterName.Empty() {
+			objs, err = c.indexer.ByIndex(kcpcache.ClusterAndNamespaceIndexName, kcpcache.ClusterAndNamespaceIndexKey(clusterName, listOpts.Namespace))
+		} else {
+			objs, err = c.indexer.ByIndex(cache.NamespaceIndex, listOpts.Namespace)
+		}
 	default:
-		objs = c.indexer.List()
+		if isClusterAware && !clusterName.Empty() {
+			objs, err = c.indexer.ByIndex(kcpcache.ClusterIndexName, kcpcache.ClusterIndexKey(clusterName))
+		} else {
+			objs = c.indexer.List()
+		}
 	}
 	if err != nil {
 		return err
@@ -177,16 +202,22 @@ func (c *CacheReader) List(_ context.Context, out client.ObjectList, opts ...cli
 	return apimeta.SetList(out, runtimeObjs)
 }
 
-func byIndexes(indexer cache.Indexer, requires fields.Requirements, namespace string) ([]interface{}, error) {
+func byIndexes(indexer cache.Indexer, requires fields.Requirements, clusterName logicalcluster.Name, namespace string) ([]interface{}, error) {
 	var (
 		err  error
 		objs []interface{}
 		vals []string
 	)
 	indexers := indexer.GetIndexers()
+	_, isClusterAware := indexers[kcpcache.ClusterAndNamespaceIndexName]
 	for idx, req := range requires {
 		indexName := FieldIndexName(req.Field)
-		indexedValue := KeyToNamespacedKey(namespace, req.Value)
+		var indexedValue string
+		if isClusterAware {
+			indexedValue = KeyToClusteredKey(clusterName.String(), namespace, req.Value)
+		} else {
+			indexedValue = KeyToNamespacedKey(namespace, req.Value)
+		}
 		if idx == 0 {
 			// we use first require to get snapshot data
 			// TODO(halfcrazy): use complicated index when client-go provides byIndexes
@@ -253,3 +284,9 @@ func KeyToNamespacedKey(ns string, baseKey string) string {
 	}
 	return allNamespacesNamespace + "/" + baseKey
 }
+
+// KeyToClusteredKey prefixes the given index key with a cluster name
+// for use in field selector indexes.
+func KeyToClusteredKey(clusterName string, ns string, baseKey string) string {
+	return clusterName + "|" + KeyToNamespacedKey(ns, baseKey)
+}