Handle VM disconnection gracefully and reorder termination logic (#626)

* Ignore VMDisconnected on detach; reorder terminate

Wrap vm.dispose() in a try/catch to ignore VMDisconnectedException when the VM has already disconnected (e.g. process terminated) to avoid spurious errors during detach. Reorder calls in DisconnectRequestHandler to invoke terminate() before detach() when terminateDebuggee is true and the session is not attached, ensuring the debuggee is terminated prior to detaching.

* Always detach debug session on terminate

Wrap debugSession.terminate() in a try/finally so debugSession.detach() is always invoked when terminateDebuggee is true and the session is not attached. This ensures the session is detached even if terminate() throws, avoiding potential dangling sessions. Other detach logic is unchanged.

Author: zepedrocosta

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/DebugSession.java

@@ -117,7 +117,11 @@ public void resume() {
 
     @Override
     public void detach() {
-        vm.dispose();
+        try {
+            vm.dispose();
+        } catch (VMDisconnectedException ex) {
+            // ignore — VM already disconnected (e.g. process was terminated first)
+        }
     }
 
     @Override

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/handler/DisconnectRequestHandler.java

@@ -26,8 +26,11 @@ public void destroyDebugSession(Command command, Arguments arguments, Response r
         IDebugSession debugSession = context.getDebugSession();
         if (debugSession != null) {
             if (disconnectArguments.terminateDebuggee && !context.isAttached()) {
-                debugSession.detach();
-                debugSession.terminate();
+                try {
+                    debugSession.terminate();
+                } finally {
+                    debugSession.detach();
+                }
             } else {
                 debugSession.detach();
             }