From 29dd22e405085b530a18218dcb78720183f4ecee Mon Sep 17 00:00:00 2001
From: sahil839 <sahilbatra839@gmail.com>
Date: Tue, 4 Aug 2020 20:10:46 +0530
Subject: [PATCH] stream_edit: Send values of changed settings only to backend.

This commit changes change_stream_privacy function to only
send the values of changed settings to backend.
We also avoid sending PATCH request if none of the settings
in stream privacy modal are changed.

This change also fixes the bug in changing stream permissions
for realms with limited plans.

Fixes #16024.
---
 static/js/stream_edit.js | 61 ++++++++++++++++++++++++++++------------
 1 file changed, 43 insertions(+), 18 deletions(-)

diff --git a/static/js/stream_edit.js b/static/js/stream_edit.js
index 11e6a7664d..ac446a8612 100644
--- a/static/js/stream_edit.js
+++ b/static/js/stream_edit.js
@@ -480,11 +480,22 @@ exports.set_stream_property = function (sub, property, value, status_element) {
     exports.bulk_set_stream_property([sub_data], status_element);
 };
 
+function get_message_retention_days_from_sub(sub) {
+    if (sub.message_retention_days === null) {
+        return "realm_default";
+    }
+    if (sub.message_retention_days === -1) {
+        return "forever";
+    }
+    return sub.message_retention_days;
+}
+
 function change_stream_privacy(e) {
     e.stopPropagation();
 
     const stream_id = $(e.target).data("stream-id");
     const sub = stream_data.get_sub_by_id(stream_id);
+    const data = {};
 
     const privacy_setting = $("#stream_privacy_modal input[name=privacy]:checked").val();
     const stream_post_policy = parseInt(
@@ -492,6 +503,10 @@ function change_stream_privacy(e) {
         10,
     );
 
+    if (sub.stream_post_policy !== stream_post_policy) {
+        data.stream_post_policy = JSON.stringify(stream_post_policy);
+    }
+
     let invite_only;
     let history_public_to_subscribers;
 
@@ -506,28 +521,38 @@ function change_stream_privacy(e) {
         history_public_to_subscribers = true;
     }
 
-    $(".stream_change_property_info").hide();
-    const data = {
-        stream_name: sub.name,
-        // toggle the privacy setting
-        is_private: JSON.stringify(invite_only),
-        stream_post_policy: JSON.stringify(stream_post_policy),
-        history_public_to_subscribers: JSON.stringify(history_public_to_subscribers),
-    };
+    if (
+        sub.invite_only !== invite_only ||
+        sub.history_public_to_subscribers !== history_public_to_subscribers
+    ) {
+        data.is_private = JSON.stringify(invite_only);
+        data.history_public_to_subscribers = JSON.stringify(history_public_to_subscribers);
+    }
 
-    if (page_params.is_owner) {
-        let message_retention_days = $(
-            "#stream_privacy_modal select[name=stream_message_retention_setting]",
-        ).val();
-        if (message_retention_days === "retain_for_period") {
-            message_retention_days = parseInt(
-                $("#stream_privacy_modal input[name=stream-message-retention-days]").val(),
-                10,
-            );
-        }
+    let message_retention_days = $(
+        "#stream_privacy_modal select[name=stream_message_retention_setting]",
+    ).val();
+    if (message_retention_days === "retain_for_period") {
+        message_retention_days = parseInt(
+            $("#stream_privacy_modal input[name=stream-message-retention-days]").val(),
+            10,
+        );
+    }
+
+    const message_retention_days_from_sub = get_message_retention_days_from_sub(sub);
+
+    if (message_retention_days_from_sub !== message_retention_days) {
         data.message_retention_days = JSON.stringify(message_retention_days);
     }
 
+    $(".stream_change_property_info").hide();
+
+    if (Object.keys(data).length === 0) {
+        overlays.close_modal("#stream_privacy_modal");
+        $("#stream_privacy_modal").remove();
+        return;
+    }
+
     channel.patch({
         url: "/json/streams/" + stream_id,
         data: data,