Kill all the child processes

Author: gspencergoog

pkgs/dart_mcp_server/lib/src/mixins/flutter_launcher.dart

@@ -227,7 +227,7 @@ base mixin FlutterLauncherSupport
     } catch (e, s) {
       log(LoggingLevel.error, 'Error launching Flutter application: $e\n$s');
       if (process != null) {
-        process.kill();
+        processManager.killPid(process.pid);
         // The exitCode handler will perform the rest of the cleanup.
       }
       return CallToolResult(
@@ -243,19 +243,19 @@ base mixin FlutterLauncherSupport
   final stopAppTool = Tool(
     name: 'stop_app',
     description:
-        'Kills a running Flutter process started by the launch_app tool.',
+        'Stops a running Flutter process started by the launch_app tool.',
     inputSchema: Schema.object(
       properties: {
         'pid': Schema.int(
-          description: 'The process ID of the process to kill.',
+          description: 'The process ID of the process to stop.',
         ),
       },
       required: ['pid'],
     ),
     outputSchema: Schema.object(
       properties: {
         'success': Schema.bool(
-          description: 'Whether the process was killed successfully.',
+          description: 'Whether the process was stopped successfully.',
         ),
       },
       required: ['success'],
@@ -274,8 +274,33 @@ base mixin FlutterLauncherSupport
         content: [TextContent(text: 'Application with PID $pid not found.')],
       );
     }
-
-    final success = processManager.killPid(pid);
+    // On Unix, killing the flutter process doesn't kill the entire process
+    // group, so we have to look for the child processes.
+    if (Platform.isLinux) {
+      final ps = processManager.runSync([
+        'ps',
+        '--no-headers',
+        '--format',
+        '%p',
+        '--ppid',
+        '$pid',
+      ]);
+      if (ps.exitCode == 0) {
+        final children = (ps.stdout as String).trim().split('\n');
+        if (children.isNotEmpty) {
+          for (final child in children) {
+            int childPid;
+            try {
+              childPid = int.parse(child);
+            } on FormatException {
+              continue;
+            }
+            processManager.killPid(childPid, ProcessSignal.sigterm);
+          }
+        }
+      }
+    }
+    final success = processManager.killPid(app.process.pid);
     if (success) {
       log(
         LoggingLevel.info,

pkgs/dart_mcp_server/test/tools/flutter_launcher_test.dart

@@ -460,6 +460,7 @@ void main() {
             'TimeoutException',
           ]),
         );
+        test.expect(mockProcessManager.killedPids, [processPid]);
 
         server.shutdown();
         client.shutdown();
@@ -504,6 +505,15 @@ void main() {
           pid: processPid,
         ),
       );
+      if (Platform.isLinux) {
+        mockProcessManager.addCommand(
+          Command(
+            ['ps', '--no-headers', '--format', '%p', '--ppid', '$processPid'],
+            stdout: '11111\n22222\n',
+            pid: processPid,
+          ),
+        );
+      }
       final serverAndClient = await createServerAndClient(
         processManager: mockProcessManager,
         fileSystem: fileSystem,
@@ -532,9 +542,9 @@ void main() {
         CallToolRequest(name: 'stop_app', arguments: {'pid': processPid}),
       );
 
-      test.expect(result.isError, test.isNot(true));
       test.expect(result.structuredContent, {'success': true});
-      test.expect(mockProcessManager.killedPids, [processPid]);
+      test.expect(mockProcessManager.killedPids, [11111, 22222, processPid]);
+      test.expect(result.isError, test.isNot(true));
       await server.shutdown();
       await client.shutdown();
     });
@@ -719,7 +729,9 @@ class MockProcessManager implements ProcessManager {
       }
     }
     throw Exception(
-      'Command not mocked: $command. Mocked commands:\n${_commands.join('\n')}',
+      'Command not mocked: "${command.join(' ')}".\n'
+      'Mocked commands:\n'
+      '${_commands.map<String>((e) => e.command.join(' ')).join('\n')}',
     );
   }
 
@@ -788,7 +800,14 @@ class MockProcessManager implements ProcessManager {
     Encoding? stdoutEncoding = systemEncoding,
     Encoding? stderrEncoding = systemEncoding,
   }) {
-    throw UnimplementedError();
+    commands.add(command);
+    final mockCommand = _findCommand(command);
+    return ProcessResult(
+      mockCommand.pid,
+      0,
+      mockCommand.stdout ?? '',
+      mockCommand.stderr ?? '',
+    );
   }
 }