Ensure that components configs are used

.. even if the subscriber got a newer generation than the
bootstrap subscriber for some reason.

1 files changed, 15 insertions, 1 deletions

diff --git a/container-core/src/main/java/com/yahoo/container/di/ConfigRetriever.java b/container-core/src/main/java/com/yahoo/container/di/ConfigRetriever.java
index aadaffe9acc..0817a87c506 100644
--- a/container-core/src/main/java/com/yahoo/container/di/ConfigRetriever.java
+++ b/container-core/src/main/java/com/yahoo/container/di/ConfigRetriever.java
@@ -81,7 +81,21 @@ public final class ConfigRetriever {
         if (newestBootstrapGeneration < leastGeneration) {
             return Optional.empty();
         }
-        return bootstrapConfigIfChanged();
+        return bootstrapConfigIfChanged()
+                // At this point, we normally assume that the bootstrap subscriber is one generation ahead
+                // of the component subscriber, but this is not always the case in practice.
+                .or(this::componentsSnapshotReceivedBeforeBootstrap);
+    }
+
+    private Optional<ConfigSnapshot> componentsSnapshotReceivedBeforeBootstrap() {
+        if (componentSubscriber.generation() == bootstrapSubscriber.generation()) {
+            // The component subscriber originally had a newer config generation than the bootstrap subscriber.
+            // Ensure that this generation is applied if it contains changed configs.
+            // The root cause is probably that the component subscriber skipped a generation and got
+            // one ahead of the bootstrap subscriber.
+            return componentsConfigIfChanged();
+        }
+        return Optional.empty();
     }
 
     private Optional<ConfigSnapshot> getComponentsSnapshot(long leastGeneration, boolean isInitializing) {