improve the warning about multiple agents

CHANGELOG.md

@@ -6,6 +6,8 @@ We use [semantic versioning](http://semver.org/):
 
 # Next version
 
+- _agent_: improved logging when multiple agents are attached
+
 # 36.1.0
 - [feature] _impacted-test-engine_: Added support for JUnit 5.13 and 6.0
 - [feature] _agent_: Added support for Java 25 and experimental support for Java 26

agent/src/main/java/com/teamscale/jacoco/agent/PreMain.java

@@ -126,8 +126,14 @@ private static Pair<AgentOptions, List<Exception>> getAndApplyAgentOptions(Strin
 		List<String> javaAgents = ManagementFactory.getRuntimeMXBean().getInputArguments().stream().filter(
 				s -> s.contains("-javaagent")).collect(Collectors.toList());
 		// We allow multiple instances of the teamscale-jacoco-agent as we ensure with the #LOCKING_SYSTEM_PROPERTY to only use it once
-		if (!javaAgents.stream().allMatch(javaAgent -> javaAgent.contains("teamscale-jacoco-agent.jar"))) {
-			delayedLogger.warn("Using multiple java agents could interfere with coverage recording.");
+		List<String> differentAgents = javaAgents.stream()
+				.filter(javaAgent -> !javaAgent.contains("teamscale-jacoco-agent.jar")).collect(
+						Collectors.toList());
+
+		if (!differentAgents.isEmpty()) {
+			delayedLogger.warn(
+					"Using multiple java agents could interfere with coverage recording: " +
+							String.join(", ", differentAgents));
 		}
 		if (!javaAgents.get(0).contains("teamscale-jacoco-agent.jar")) {
 			delayedLogger.warn("For best results consider registering the Teamscale Java Profiler first.");

system-tests/multiple-agents-test/src/test/kotlin/com/teamscale/client/MultipleAgentsTest.kt

@@ -13,7 +13,7 @@ class MultipleAgentsTest {
 		assertThat(LOG_DIRECTORY).exists()
 		val lines = LOG_DIRECTORY.resolve("teamscale-jacoco-agent.log").readLines()
 		assertThat(lines)
-			.anyMatch { it.contains("Using multiple java agents could interfere with coverage recording.") }
+			.anyMatch { it.contains("Using multiple java agents could interfere with coverage recording") }
 		assertThat(lines)
 			.anyMatch { it.contains("For best results consider registering the Teamscale Java Profiler first.") }
 	}