From b9afedbea1e1c85c97c97f1a7e41c17291ea7105 Mon Sep 17 00:00:00 2001
From: Suresh Sigera <ssigera@proton.me>
Date: Thu, 10 Sep 2026 23:07:15 -0400
Subject: [PATCH] fix: don't default null replicas/readyReplicas in Readiness
 checks

isReplicaSetReady and isReplicationControllerReady silently treated a
null spec.replicas as 1 and null status.readyReplicas as 0, which can
misreport readiness. isStatefulSetReady already had this exact issue
fixed by a maintainer in a prior review - this applies the same fix
to the two remaining copy-pasted methods, plus regression tests.
---
 .../io/kubernetes/client/util/Readiness.java  |  8 +--
 .../kubernetes/client/util/ReadinessTest.java | 50 ++++++++++++++++++-
 2 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/util/src/main/java/io/kubernetes/client/util/Readiness.java b/util/src/main/java/io/kubernetes/client/util/Readiness.java
index 715320574e..90191f7cc4 100644
--- a/util/src/main/java/io/kubernetes/client/util/Readiness.java
+++ b/util/src/main/java/io/kubernetes/client/util/Readiness.java
@@ -206,10 +206,10 @@ public static boolean isReplicaSetReady(V1ReplicaSet replicaSet) {
         Integer readyReplicas = status.getReadyReplicas();
 
         if (replicas == null) {
-            replicas = 1;
+            return false;
         }
         if (readyReplicas == null) {
-            readyReplicas = 0;
+            return false;
         }
 
         return replicas.equals(readyReplicas);
@@ -380,10 +380,10 @@ public static boolean isReplicationControllerReady(V1ReplicationController repli
         Integer readyReplicas = status.getReadyReplicas();
 
         if (replicas == null) {
-            replicas = 1;
+            return false;
         }
         if (readyReplicas == null) {
-            readyReplicas = 0;
+            return false;
         }
 
         return replicas.equals(readyReplicas);
diff --git a/util/src/test/java/io/kubernetes/client/util/ReadinessTest.java b/util/src/test/java/io/kubernetes/client/util/ReadinessTest.java
index e1683f0c44..f47a1709ac 100644
--- a/util/src/test/java/io/kubernetes/client/util/ReadinessTest.java
+++ b/util/src/test/java/io/kubernetes/client/util/ReadinessTest.java
@@ -222,6 +222,30 @@ void isReplicaSetReady_notAllReplicasReady_returnsFalse() {
         assertThat(Readiness.isReplicaSetReady(replicaSet)).isFalse();
     }
 
+    @Test
+    void isReplicaSetReady_nullSpecReplicas_returnsFalse() {
+        // Regression test: a null spec.replicas must not be silently treated as "1".
+        V1ReplicaSet replicaSet = new V1ReplicaSet()
+                .metadata(new V1ObjectMeta().name("test"))
+                .spec(new V1ReplicaSetSpec())
+                .status(new V1ReplicaSetStatus().readyReplicas(1));
+        assertThat(Readiness.isReplicaSetReady(replicaSet)).isFalse();
+    }
+
+    @Test
+    void isReplicaSetReady_nullReadyReplicas_returnsFalse() {
+        // Regression test: a null status.readyReplicas must not be silently treated as "0".
+        // Uses spec.replicas(0) specifically: under the old buggy code, a null readyReplicas
+        // defaulted to 0, so 0.equals(0) would wrongly report "ready" here. A non-zero
+        // replicas value wouldn't actually catch that bug, since it wouldn't match the
+        // default of 0 either way.
+        V1ReplicaSet replicaSet = new V1ReplicaSet()
+                .metadata(new V1ObjectMeta().name("test"))
+                .spec(new V1ReplicaSetSpec().replicas(0))
+                .status(new V1ReplicaSetStatus());
+        assertThat(Readiness.isReplicaSetReady(replicaSet)).isFalse();
+    }
+
     // ========== DaemonSet Tests ==========
 
     @Test
@@ -337,6 +361,30 @@ void isReplicationControllerReady_allReplicasReady_returnsTrue() {
         assertThat(Readiness.isReplicationControllerReady(rc)).isTrue();
     }
 
+    @Test
+    void isReplicationControllerReady_nullSpecReplicas_returnsFalse() {
+        // Regression test: a null spec.replicas must not be silently treated as "1".
+        V1ReplicationController rc = new V1ReplicationController()
+                .metadata(new V1ObjectMeta().name("test"))
+                .spec(new io.kubernetes.client.openapi.models.V1ReplicationControllerSpec())
+                .status(new V1ReplicationControllerStatus().readyReplicas(1));
+        assertThat(Readiness.isReplicationControllerReady(rc)).isFalse();
+    }
+
+    @Test
+    void isReplicationControllerReady_nullReadyReplicas_returnsFalse() {
+        // Regression test: a null status.readyReplicas must not be silently treated as "0".
+        // Uses spec.replicas(0) specifically: under the old buggy code, a null readyReplicas
+        // defaulted to 0, so 0.equals(0) would wrongly report "ready" here. A non-zero
+        // replicas value wouldn't actually catch that bug, since it wouldn't match the
+        // default of 0 either way.
+        V1ReplicationController rc = new V1ReplicationController()
+                .metadata(new V1ObjectMeta().name("test"))
+                .spec(new io.kubernetes.client.openapi.models.V1ReplicationControllerSpec().replicas(0))
+                .status(new V1ReplicationControllerStatus());
+        assertThat(Readiness.isReplicationControllerReady(rc)).isFalse();
+    }
+
     // ========== PersistentVolumeClaim Tests ==========
 
     @Test
@@ -447,4 +495,4 @@ void isReady_delegatesToCorrectMethod_forJob() {
                                         .status("True"))));
         assertThat(Readiness.isReady(job)).isTrue();
     }
-}
+}
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