From b245bbb8d64bd5becc2d28574945bbb63c3b1872 Mon Sep 17 00:00:00 2001
From: Andrew <15331990+ahuang11@users.noreply.github.com>
Date: Thu, 13 Feb 2025 14:08:41 -0800
Subject: [PATCH] Fix visible range on objects set in Feed (#7673)

---
 panel/layout/feed.py               | 12 +++++++++++-
 panel/tests/ui/layout/test_feed.py | 14 ++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/panel/layout/feed.py b/panel/layout/feed.py
index eeec31dfc9..fa172732d4 100644
--- a/panel/layout/feed.py
+++ b/panel/layout/feed.py
@@ -6,7 +6,7 @@
 import param
 
 from ..models.feed import Feed as PnFeed, ScrollButtonClick, ScrollLatestEvent
-from ..util import edit_readonly
+from ..util import edit_readonly, isIn
 from .base import Column
 
 if TYPE_CHECKING:
@@ -154,6 +154,16 @@ def _get_objects(
         self, model: Model, old_objects: list[Viewable], doc: Document,
         root: Model, comm: Comm | None = None
     ):
+        # If no previously visible objects are visible now, reset the visible range
+        events = self._in_process__events.get(doc, {})
+        if (
+            self._last_synced and
+            'visible_range' not in events and
+            not any(isIn(old_objects[i], self.objects) for i in range(*self._last_synced))
+        ):
+            with edit_readonly(self):
+                self.visible_range = None
+
         from ..pane.base import RerenderError
         new_models, old_models = [], []
         self._last_synced = self._synced_range
diff --git a/panel/tests/ui/layout/test_feed.py b/panel/tests/ui/layout/test_feed.py
index 4e6e6fe1ff..adb826c9e3 100644
--- a/panel/tests/ui/layout/test_feed.py
+++ b/panel/tests/ui/layout/test_feed.py
@@ -160,3 +160,17 @@ def test_feed_dynamic_objects(page):
 
     wait_until(lambda: expect(page.locator('pre').first).to_have_text('0'))
     wait_until(lambda: page.locator('pre').count() > 10, page)
+
+def test_feed_reset_visible_range(page):
+    feed = Feed(*list(range(ITEMS)), load_buffer=20, height=50, view_latest=True)
+    serve_component(page, feed)
+
+    wait_until(lambda: int(page.locator('pre').last.inner_text() or 0) == 99, page)
+
+    # set objects to 20
+    feed.objects = feed.objects[:20]
+
+    # assert view reset
+    wait_until(lambda: (
+        int(page.locator('pre').last.inner_text() or 0) == 19
+    ), page)