fix(kotlin): Kill Gradle daemons on KLS shutdown

src/solidlsp/language_servers/kotlin_language_server.py

@@ -23,6 +23,7 @@
 import threading
 from typing import cast
 
+import psutil
 from overrides import override
 
 from solidlsp.ls import (
@@ -554,3 +555,49 @@ def progress_handler(params: dict) -> None:
     def _get_wait_time_for_cross_file_referencing(self) -> float:
         """Small safety buffer since we already waited for indexing to complete in _start_server."""
         return 1.0
+
+    @override
+    def stop(self, shutdown_timeout: float = 2.0) -> None:
+        assert isinstance(self._dependency_provider, self.DependencyProvider)
+        java_home = self._dependency_provider._java_home_path
+        assert java_home is not None
+        super().stop(shutdown_timeout=shutdown_timeout)
+        self._kill_gradle_daemons(java_home)
+
+    @staticmethod
+    def _kill_gradle_daemons(java_home: str) -> None:
+        """Kill Gradle daemons spawned by KLS during project indexing.
+
+        KLS triggers Gradle during indexing, which spawns persistent daemon processes that
+        outlive the KLS process (3-hour idle timeout, ~500MB RSS each). These daemons are
+        not children of KLS and are invisible to normal process-tree cleanup.
+
+        We identify them by matching the java executable in their command line against
+        the JAVA_HOME used by this KLS instance.
+        """
+        java_bin_resolved = os.path.realpath(os.path.join(java_home, "bin", "java"))
+
+        killed: list[psutil.Process] = []
+        for proc in psutil.process_iter(["pid", "cmdline"]):
+            try:
+                cmdline = proc.info["cmdline"]
+                if not cmdline:
+                    continue
+                if not any("GradleDaemon" in arg for arg in cmdline):
+                    continue
+                # cmdline[0] is the java binary path used to start the daemon
+                if os.path.realpath(cmdline[0]) == java_bin_resolved:
+                    log.info("Terminating Gradle daemon (PID %d) spawned by KLS", proc.pid)
+                    proc.terminate()
+                    killed.append(proc)
+            except (psutil.NoSuchProcess, psutil.AccessDenied, psutil.ZombieProcess):
+                continue
+
+        if killed:
+            _, alive = psutil.wait_procs(killed, timeout=5)
+            for proc in alive:
+                log.warning("Gradle daemon (PID %d) did not terminate gracefully, killing", proc.pid)
+                try:
+                    proc.kill()
+                except (psutil.NoSuchProcess, psutil.AccessDenied):
+                    pass