api: Add prevContentSha256 param to updateMessage route

Author: chrisbobbe

lib/api/route/messages.dart

@@ -267,6 +267,9 @@ class SendMessageResult {
 }
 
 /// https://zulip.com/api/update-message
+///
+/// `prev_content_sha256` is sent if the feature level is >= 379,
+/// otherwise ignored.
 Future<UpdateMessageResult> updateMessage(
   ApiConnection connection, {
   required int messageId,
@@ -276,6 +279,7 @@ Future<UpdateMessageResult> updateMessage(
   bool? sendNotificationToNewThread,
   String? content,
   int? streamId,
+  String? prevContentSha256,
 }) {
   return connection.patch('updateMessage', UpdateMessageResult.fromJson, 'messages/$messageId', {
     if (topic != null) 'topic': RawParameter(topic.apiName),
@@ -284,6 +288,8 @@ Future<UpdateMessageResult> updateMessage(
     if (sendNotificationToNewThread != null) 'send_notification_to_new_thread': sendNotificationToNewThread,
     if (content != null) 'content': RawParameter(content),
     if (streamId != null) 'stream_id': streamId,
+    // TODO(server-11) remove FL condition and its mention in the dartdoc
+    if (prevContentSha256 != null && connection.zulipFeatureLevel! >= 379) 'prev_content_sha256': RawParameter(prevContentSha256),
   });
 }
 

test/api/route/messages_test.dart

@@ -455,6 +455,7 @@ void main() {
       bool? sendNotificationToNewThread,
       String? content,
       int? streamId,
+      String? prevContentSha256,
       required Map<String, String> expected,
     }) async {
       final result = await updateMessage(connection,
@@ -465,14 +466,43 @@ void main() {
         sendNotificationToNewThread: sendNotificationToNewThread,
         content: content,
         streamId: streamId,
+        prevContentSha256: prevContentSha256,
       );
       check(connection.lastRequest).isA<http.Request>()
         ..method.equals('PATCH')
         ..url.path.equals('/api/v1/messages/$messageId')
-        ..bodyFields.deepEquals(expected);
+        ..bodyFields.deepEquals(expected)
+        ..bodyFields.length.equals(expected.length);
       return result;
     }
 
+    test('pure content change', () {
+      return FakeApiConnection.with_((connection) async {
+        connection.prepare(json: UpdateMessageResult().toJson());
+        await checkUpdateMessage(connection,
+          messageId: eg.streamMessage().id,
+          content: 'asdf',
+          prevContentSha256: '34a780ad578b997db55b260beb60b501f3e04d30ba1a51fcf43cd8dd1241780d',
+          expected: {
+            'content': 'asdf',
+            'prev_content_sha256': '34a780ad578b997db55b260beb60b501f3e04d30ba1a51fcf43cd8dd1241780d',
+          });
+      });
+    });
+
+    test('pure content change (legacy, before prev_content_sha256)', () {
+      return FakeApiConnection.with_(zulipFeatureLevel: 378, (connection) async {
+        connection.prepare(json: UpdateMessageResult().toJson());
+        await checkUpdateMessage(connection,
+          messageId: eg.streamMessage().id,
+          content: 'asdf',
+          prevContentSha256: '34a780ad578b997db55b260beb60b501f3e04d30ba1a51fcf43cd8dd1241780d',
+          expected: {
+            'content': 'asdf',
+          });
+      });
+    });
+
     test('topic/content change', () {
       // A separate test exercises `streamId`;
       // the API doesn't allow changing channel and content at the same time.