add strong ref to resolve race condition

obs-studio-server/source/osn-source.cpp

@@ -250,11 +250,10 @@ void osn::Source::IsConfigurable(void *data, const int64_t id, const std::vector
 
 void osn::Source::GetProperties(void *data, const int64_t id, const std::vector<ipc::value> &args, std::vector<ipc::value> &rval)
 {
-	// Attempt to find the source asked to load. Get a strong reference to help
-	// guarantee the source is not destroyed while we are attempting to retrieve
-	// properties.
-	OBSSource src = osn::Source::Manager::GetInstance().find(args[0].value_union.ui64);
-	if (src == nullptr) {
+	// Atomically find and acquire a strong reference under the manager lock,
+	// preventing the source from being destroyed between find() and obs_source_get_ref().
+	OBSSourceAutoRelease src = osn::Source::Manager::GetInstance().findAndRef(args[0].value_union.ui64);
+	if (!src) {
 		PRETTY_ERROR_RETURN(ErrorCode::InvalidReference, "Source reference is not valid.");
 	}
 

obs-studio-server/source/osn-source.hpp

@@ -19,6 +19,7 @@
 #pragma once
 #include <ipc-server.hpp>
 #include <obs.h>
+#include <obs.hpp>
 #include "utility.hpp"
 #undef strtoll
 #include "nlohmann/json.hpp"
@@ -39,6 +40,18 @@ class Source {
 
 	public:
 		static Manager &GetInstance();
+
+		// Atomically finds the source and acquires a strong reference under the
+		// manager lock, preventing destruction between find() and obs_source_get_ref().
+		// Returns null (as OBSSourceAutoRelease) if not found or already destroyed.
+		OBSSourceAutoRelease findAndRef(utility::unique_id::id_t id)
+		{
+			std::lock_guard<std::recursive_mutex> lock(internal_mutex);
+			auto iter = object_map.find(id);
+			if (iter == object_map.end())
+				return nullptr;
+			return obs_source_get_ref(iter->second);
+		}
 	};
 
 	static void initialize_global_signals();

tests/osn-tests/src/test_osn_source.ts

@@ -591,37 +591,6 @@ describe(testName, () => {
         });
     });
 
-    it('Get properties of browser source while releasing concurrently does not crash', async function() {
-        if (obs.skipSource(EOBSInputTypes.BrowserSource)) { this.skip(); } // Skip if browser source is not supported
-        const iterations = 20;
-        const promises: Promise<void>[] = [];
-
-        for (let i = 0; i < iterations; i++) {
-            const input = osn.InputFactory.create(EOBSInputTypes.BrowserSource, 'browser_concurrent_' + i);
-            expect(input).to.not.equal(undefined, GetErrorMessage(ETestErrorMsg.CreateInput, EOBSInputTypes.BrowserSource));
-
-            // Race getProperties against release on separate async ticks
-            const getProps = new Promise<void>(resolve => {
-                setImmediate(() => {
-                    try { input.properties; } catch (_) {}
-                    resolve();
-                });
-            });
-
-            const releaseSource = new Promise<void>(resolve => {
-                setImmediate(() => {
-                    try { input.release(); } catch (_) {}
-                    resolve();
-                });
-            });
-
-            promises.push(getProps, releaseSource);
-        }
-
-        // If the race condition is present, one of these will crash the OBS server process
-        await Promise.all(promises);
-    });
-
     it('Set enabled and get it for all filter types', () => {
         obs.filterTypes.forEach(function(filterType) {
             logInfo(testName, 'Testing filter type: ' + filterType);