do_change_stream_invite_only: Ensure stream is not web public.

When changing stream permissions to invite_only or public, ensure
that stream doesn't have is_web_public set to True.

templates/zerver/api/changelog.md

@@ -13,6 +13,11 @@ below features are supported.
 
 **Feature level 70**
 
+* [`GET /events`](/api/get-events): Added `is_web_public` field to
+  `stream` events changing `invite_only`.
+
+**Feature level 70**
+
 * [`POST /register`](/api/register-queue): Added new top-level
   `server_timestamp` field when fetching presence data, to match the
   existing presence API.

version.py

@@ -32,7 +32,7 @@ DESKTOP_WARNING_VERSION = "5.4.3"
 #
 # Changes should be accompanied by documentation explaining what the
 # new level means in templates/zerver/api/changelog.md.
-API_FEATURE_LEVEL = 70
+API_FEATURE_LEVEL = 71
 
 # Bump the minor PROVISION_VERSION to indicate that folks should provision
 # only when going from an old version of the code to a newer version. Bump

zerver/lib/actions.py

@@ -4554,13 +4554,15 @@ def do_change_stream_invite_only(
     )
     stream.invite_only = invite_only
     stream.history_public_to_subscribers = history_public_to_subscribers
-    stream.save(update_fields=["invite_only", "history_public_to_subscribers"])
+    stream.is_web_public = False
+    stream.save(update_fields=["invite_only", "history_public_to_subscribers", "is_web_public"])
     event = dict(
         op="update",
         type="stream",
         property="invite_only",
         value=invite_only,
         history_public_to_subscribers=history_public_to_subscribers,
+        is_web_public=False,
         stream_id=stream.id,
         name=stream.name,
     )

zerver/lib/event_schema.py

@@ -1183,6 +1183,7 @@ stream_update_event = event_dict_type(
     optional_keys=[
         ("rendered_description", str),
         ("history_public_to_subscribers", bool),
+        ("is_web_public", bool),
     ],
 )
 _check_stream_update = make_checker(stream_update_event)
@@ -1213,7 +1214,7 @@ def check_stream_update(
         assert extra_keys == set()
         assert isinstance(value, str)
     elif prop == "invite_only":
-        assert extra_keys == {"history_public_to_subscribers"}
+        assert extra_keys == {"history_public_to_subscribers", "is_web_public"}
         assert isinstance(value, bool)
     elif prop == "message_retention_days":
         assert extra_keys == set()

zerver/openapi/zulip.yaml

@@ -1085,6 +1085,14 @@ paths:
                                     Currently always true for public streams (i.e. invite_only=False implies
                                     history_public_to_subscribers=True), but clients should not make that
                                     assumption, as we may change that behavior in the future.
+                                is_web_public:
+                                  type: boolean
+                                  description: |
+                                    Note: Only present if the changed property was `invite_only`.
+
+                                    Whether the stream's history is now readable by web-public visitors.
+
+                                    **Changes**: New in Zulip 5.0 (feature level 71).
                               additionalProperties: false
                               example:
                                 {
@@ -1093,6 +1101,7 @@ paths:
                                   "property": "invite_only",
                                   "value": true,
                                   "history_public_to_subscribers": true,
+                                  "is_web_public": false,
                                   "stream_id": 11,
                                   "name": "test_stream",
                                   "id": 0,