From 0caaf30cab67090e093039222f084f128701baf9 Mon Sep 17 00:00:00 2001
From: Rafael Winterhalter <rafael.wth@gmail.com>
Date: Wed, 8 Mar 2023 09:43:02 +0100
Subject: [PATCH] Throw exception on asking for configuration that is not
 available.

---
 .../java/co/elastic/apm/agent/impl/ElasticApmTracer.java | 9 ++++++---
 .../main/java/co/elastic/apm/agent/impl/NoopTracer.java  | 2 +-
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/apm-agent-core/src/main/java/co/elastic/apm/agent/impl/ElasticApmTracer.java b/apm-agent-core/src/main/java/co/elastic/apm/agent/impl/ElasticApmTracer.java
index 3f9a09a6076..8273b1f8d1e 100644
--- a/apm-agent-core/src/main/java/co/elastic/apm/agent/impl/ElasticApmTracer.java
+++ b/apm-agent-core/src/main/java/co/elastic/apm/agent/impl/ElasticApmTracer.java
@@ -378,11 +378,14 @@ public ConfigurationRegistry getConfigurationRegistry() {
     @Override
     @SuppressWarnings({"unchecked", "rawtypes"})
     public <T> T getConfig(Class<T> configProvider) {
+        T configuration = null;
         if (ConfigurationOptionProvider.class.isAssignableFrom(configProvider)) {
-            return (T) configurationRegistry.getConfig((Class) configProvider);
-        } else {
-            return null;
+             configuration = (T) configurationRegistry.getConfig((Class) configProvider);
+        }
+        if (configuration == null) {
+            throw new IllegalStateException("no configuration available for " + configProvider.getName());
         }
+        return configuration;
     }
 
     public void endTransaction(Transaction transaction) {
diff --git a/apm-agent-core/src/main/java/co/elastic/apm/agent/impl/NoopTracer.java b/apm-agent-core/src/main/java/co/elastic/apm/agent/impl/NoopTracer.java
index 76dc5f7db76..aff87d21c47 100644
--- a/apm-agent-core/src/main/java/co/elastic/apm/agent/impl/NoopTracer.java
+++ b/apm-agent-core/src/main/java/co/elastic/apm/agent/impl/NoopTracer.java
@@ -169,7 +169,7 @@ public <T extends co.elastic.apm.agent.tracer.Tracer> T require(Class<T> type) {
 
     @Override
     public <T> T getConfig(Class<T> configuration) {
-        return null;
+        throw new IllegalStateException();
     }
 
     @Override