[analysis_server] Allow action in response to showMessageRequest to be null

This allows for users to dismiss a notification without taking any action (something that VS Code / LSP allows for but this API did not).

Change-Id: Icf384008cfcfde6f150c63d3f2889e81e79d1dc1
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/292080
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/doc/api.html

@@ -627,7 +627,7 @@ a:focus, a:hover {
   "id": String
   "error": <span style="color:#999999">optional</span> <a href="#type_RequestError">RequestError</a>
   "result": {
-    "<b>action</b>": String
+    "<b>action</b>": <span style="color:#999999">optional</span> String
   }
 }</pre></div>
     <p><b>Note:</b> This is a request from the server to the client.</p>
@@ -666,10 +666,12 @@ a:focus, a:hover {
         <p>
           The labels of the buttons by which the user can dismiss the message.
         </p>
-      </dd></dl><h4>returns:</h4><dl><dt class="field"><b>action: String</b></dt><dd>
+      </dd></dl><h4>returns:</h4><dl><dt class="field"><b>action: String<span style="color:#999999"> (optional)</span></b></dt><dd>
         
         <p>
-          The label of the action that was selected by the user.
+          The label of the action that was selected by the user. May be
+          omitted or `null` if the user dismissed the message without
+          clicking an action button.
         </p>
       </dd></dl></dd></dl><h3>Notifications</h3><dl><dt class="notification"><a name="notification_server.connected">server.connected</a></dt><dd><div class="box"><pre>notification: {
   "event": "server.connected"

pkg/analysis_server/lib/protocol/protocol_generated.dart

@@ -16717,27 +16717,27 @@ class ServerShowMessageRequestParams implements RequestParams {
 /// server.showMessageRequest result
 ///
 /// {
-///   "action": String
+///   "action": optional String
 /// }
 ///
 /// Clients may not extend, implement or mix-in this class.
 class ServerShowMessageRequestResult implements ResponseResult {
-  /// The label of the action that was selected by the user.
-  String action;
+  /// The label of the action that was selected by the user. May be omitted or
+  /// `null` if the user dismissed the message without clicking an action
+  /// button.
+  String? action;
 
-  ServerShowMessageRequestResult(this.action);
+  ServerShowMessageRequestResult({this.action});
 
   factory ServerShowMessageRequestResult.fromJson(
       JsonDecoder jsonDecoder, String jsonPath, Object? json) {
     json ??= {};
     if (json is Map) {
-      String action;
+      String? action;
       if (json.containsKey('action')) {
         action = jsonDecoder.decodeString('$jsonPath.action', json['action']);
-      } else {
-        throw jsonDecoder.mismatch(jsonPath, 'action');
       }
-      return ServerShowMessageRequestResult(action);
+      return ServerShowMessageRequestResult(action: action);
     } else {
       throw jsonDecoder.mismatch(
           jsonPath, 'server.showMessageRequest result', json);
@@ -16754,7 +16754,10 @@ class ServerShowMessageRequestResult implements ResponseResult {
   @override
   Map<String, Object> toJson() {
     var result = <String, Object>{};
-    result['action'] = action;
+    var action = this.action;
+    if (action != null) {
+      result['action'] = action;
+    }
     return result;
   }
 

pkg/analysis_server/test/domain_server_test.dart

@@ -152,11 +152,27 @@ class ServerDomainTest extends PubPackageAnalysisServerTest {
     // Simulate the response.
     var request = serverChannel.serverRequestsSent[0];
     await serverChannel.simulateResponseFromClient(
-        ServerShowMessageRequestResult('a').toResponse(request.id));
+        ServerShowMessageRequestResult(action: 'a').toResponse(request.id));
     var response = await responseFuture;
     expect(response, 'a');
   }
 
+  Future<void> test_showMessage_nullResponse() async {
+    server.clientCapabilities.requests = ['showMessageRequest'];
+
+    // Send the request.
+    var responseFuture =
+        server.showUserPrompt(MessageType.warning, 'message', ['a', 'b']);
+    expect(serverChannel.serverRequestsSent, hasLength(1));
+
+    // Simulate the response.
+    var request = serverChannel.serverRequestsSent[0];
+    await serverChannel.simulateResponseFromClient(
+        ServerShowMessageRequestResult().toResponse(request.id));
+    var response = await responseFuture;
+    expect(response, isNull);
+  }
+
   Future<void> test_shutdown() async {
     var request = ServerShutdownParams().toRequest('0');
     await handleSuccessfulRequest(request);

pkg/analysis_server/test/integration/support/integration_test_methods.dart

@@ -161,9 +161,11 @@ abstract class IntegrationTest {
   ///
   /// Returns
   ///
-  /// action: String
+  /// action: String (optional)
   ///
-  ///   The label of the action that was selected by the user.
+  ///   The label of the action that was selected by the user. May be omitted
+  ///   or `null` if the user dismissed the message without clicking an action
+  ///   button.
   Future<ServerShowMessageRequestResult> sendServerShowMessageRequest(
       MessageType type, String message, List<MessageAction> actions) async {
     var params =

pkg/analysis_server/test/integration/support/protocol_matchers.dart

@@ -3135,11 +3135,11 @@ final Matcher isServerShowMessageRequestParams = LazyMatcher(() =>
 /// server.showMessageRequest result
 ///
 /// {
-///   "action": String
+///   "action": optional String
 /// }
 final Matcher isServerShowMessageRequestResult = LazyMatcher(() =>
-    MatchesJsonObject(
-        'server.showMessageRequest result', {'action': isString}));
+    MatchesJsonObject('server.showMessageRequest result', null,
+        optionalFields: {'action': isString}));
 
 /// server.shutdown params
 final Matcher isServerShutdownParams = isNull;

pkg/analysis_server/tool/spec/spec_input.html

@@ -451,10 +451,12 @@
       </field>
     </params>
     <result>
-      <field name="action">
+      <field name="action" optional="true">
         <ref>String</ref>
         <p>
-          The label of the action that was selected by the user.
+          The label of the action that was selected by the user. May be
+          omitted or `null` if the user dismissed the message without
+          clicking an action button.
         </p>
       </field>
     </result>

pkg/analysis_server_client/lib/src/protocol/protocol_generated.dart

@@ -16717,27 +16717,27 @@ class ServerShowMessageRequestParams implements RequestParams {
 /// server.showMessageRequest result
 ///
 /// {
-///   "action": String
+///   "action": optional String
 /// }
 ///
 /// Clients may not extend, implement or mix-in this class.
 class ServerShowMessageRequestResult implements ResponseResult {
-  /// The label of the action that was selected by the user.
-  String action;
+  /// The label of the action that was selected by the user. May be omitted or
+  /// `null` if the user dismissed the message without clicking an action
+  /// button.
+  String? action;
 
-  ServerShowMessageRequestResult(this.action);
+  ServerShowMessageRequestResult({this.action});
 
   factory ServerShowMessageRequestResult.fromJson(
       JsonDecoder jsonDecoder, String jsonPath, Object? json) {
     json ??= {};
     if (json is Map) {
-      String action;
+      String? action;
       if (json.containsKey('action')) {
         action = jsonDecoder.decodeString('$jsonPath.action', json['action']);
-      } else {
-        throw jsonDecoder.mismatch(jsonPath, 'action');
       }
-      return ServerShowMessageRequestResult(action);
+      return ServerShowMessageRequestResult(action: action);
     } else {
       throw jsonDecoder.mismatch(
           jsonPath, 'server.showMessageRequest result', json);
@@ -16754,7 +16754,10 @@ class ServerShowMessageRequestResult implements ResponseResult {
   @override
   Map<String, Object> toJson() {
     var result = <String, Object>{};
-    result['action'] = action;
+    var action = this.action;
+    if (action != null) {
+      result['action'] = action;
+    }
     return result;
   }