From abec42e9190ae00b0f21f8ecb61c1d8203016943 Mon Sep 17 00:00:00 2001
From: SendableMetatype <263203301+SendableMetatype@users.noreply.github.com>
Date: Sun, 6 Sep 2026 19:25:48 +0200
Subject: [PATCH] fix: keep libwebrtc quiet by default and make logToDebug work
 again

Since the m152 update, libwebrtc initializes its logging configuration
on the first log line, with everything from LS_INFO upwards written to
stderr, and that configuration can be set only once. Its debug output
no longer consults the severity set by LogMessage::LogToDebug, so
Logging.logToDebug had no effect and every application got the full
INFO log on stderr, on every platform.

The library now initializes the configuration when it is loaded, with
the debug output disabled, which restores the previous behavior of
staying silent unless asked. Logging.logToDebug registers a log sink
that writes to the debugger output on Windows and to stderr elsewhere,
which is where libwebrtc wrote before; a sink can be added and removed
at any time, so the severity remains adjustable at runtime.
---
 webrtc-jni/src/main/cpp/src/JNI_Logging.cpp   | 49 ++++++++++++++++++-
 webrtc-jni/src/main/cpp/src/JNI_WebRTC.cpp    | 12 +++++
 .../onvoid/webrtc/logging/LoggingTests.java   |  9 ++++
 3 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/webrtc-jni/src/main/cpp/src/JNI_Logging.cpp b/webrtc-jni/src/main/cpp/src/JNI_Logging.cpp
index 6e680aa0..ff2252e6 100644
--- a/webrtc-jni/src/main/cpp/src/JNI_Logging.cpp
+++ b/webrtc-jni/src/main/cpp/src/JNI_Logging.cpp
@@ -23,7 +23,38 @@
 
 #include "rtc_base/logging.h"
 
+#include <cstdio>
 #include <memory>
+#include <mutex>
+
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
+namespace
+{
+	// libwebrtc no longer lets LogMessage::LogToDebug change the severity of its
+	// own debug output after the logging configuration is initialized. A sink
+	// registered with AddLogToStream can be added and removed at any time, so
+	// logToDebug is implemented with one that writes where libwebrtc used to:
+	// the debugger output on Windows and stderr everywhere.
+	class DebugLogSink : public webrtc::LogSink
+	{
+		public:
+			void OnLogMessage(const std::string & message) override
+			{
+#ifdef _WIN32
+				OutputDebugStringA(message.c_str());
+#endif
+				fputs(message.c_str(), stderr);
+				fflush(stderr);
+			}
+	};
+
+	DebugLogSink debugLogSink;
+	bool debugLogSinkAttached = false;
+	std::mutex debugLogSinkMutex;
+}
 
 JNIEXPORT void JNICALL Java_dev_onvoid_webrtc_logging_Logging_addLogSink
 (JNIEnv * env, jclass caller, jobject jseverity, jobject jsink)
@@ -53,8 +84,22 @@ JNIEXPORT void JNICALL Java_dev_onvoid_webrtc_logging_Logging_logToDebug
 {
 	int rtcSeverity = jni::JavaEnums::toNative<webrtc::LoggingSeverity>(env, jseverity);
 
-	if (rtcSeverity >= webrtc::LS_VERBOSE && rtcSeverity <= webrtc::LS_NONE) {
-		webrtc::LogMessage::LogToDebug(static_cast<webrtc::LoggingSeverity>(rtcSeverity));
+	if (rtcSeverity < webrtc::LS_VERBOSE || rtcSeverity > webrtc::LS_NONE) {
+		return;
+	}
+
+	auto severity = static_cast<webrtc::LoggingSeverity>(rtcSeverity);
+
+	std::lock_guard<std::mutex> lock(debugLogSinkMutex);
+
+	if (debugLogSinkAttached) {
+		webrtc::LogMessage::RemoveLogToStream(&debugLogSink);
+		debugLogSinkAttached = false;
+	}
+
+	if (severity != webrtc::LS_NONE) {
+		webrtc::LogMessage::AddLogToStream(&debugLogSink, severity);
+		debugLogSinkAttached = true;
 	}
 }
 
diff --git a/webrtc-jni/src/main/cpp/src/JNI_WebRTC.cpp b/webrtc-jni/src/main/cpp/src/JNI_WebRTC.cpp
index 4ac8813a..b932822d 100644
--- a/webrtc-jni/src/main/cpp/src/JNI_WebRTC.cpp
+++ b/webrtc-jni/src/main/cpp/src/JNI_WebRTC.cpp
@@ -19,6 +19,8 @@
 #include "JavaUtils.h"
 #include "WebRTCContext.h"
 
+#include "rtc_base/logging.h"
+
 #include <jni.h>
 
 jni::JavaContext * javaContext = nullptr;
@@ -31,6 +33,16 @@ JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM * vm, void * reserved)
 		return -1;
 	}
 
+	// libwebrtc initializes its logging configuration on the first log line,
+	// with everything from LS_INFO upwards written to stderr, and the
+	// configuration can be set only once. Initialize it here, before anything
+	// can log, so nothing is written unless the application asks for it through
+	// Logging.logToDebug or a log sink.
+	webrtc::LoggingConfig loggingConfig;
+	loggingConfig.set_min_severity(webrtc::LS_NONE);
+	loggingConfig.set_debug_severity(webrtc::LS_NONE);
+	webrtc::InitializeLogging(std::move(loggingConfig));
+
 	javaContext = new jni::WebRTCContext(vm);
 
 	try {
diff --git a/webrtc/src/test/java/dev/onvoid/webrtc/logging/LoggingTests.java b/webrtc/src/test/java/dev/onvoid/webrtc/logging/LoggingTests.java
index efeb9f17..15920629 100644
--- a/webrtc/src/test/java/dev/onvoid/webrtc/logging/LoggingTests.java
+++ b/webrtc/src/test/java/dev/onvoid/webrtc/logging/LoggingTests.java
@@ -29,6 +29,15 @@
 
 class LoggingTests {
 
+	@Test
+	void logToDebug() {
+		Logging.logToDebug(Severity.ERROR);
+		Logging.error("logToDebug at ERROR");
+		Logging.logToDebug(Severity.INFO);
+		Logging.logToDebug(Severity.NONE);
+		Logging.info("logToDebug at NONE must not print this");
+	}
+
 	@Test
 	void logInfo() throws Exception {
 		CountDownLatch latch = new CountDownLatch(3);