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perf(social): cap feed length to stop long browsing sessions going ch… #44

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perf(social): cap feed length to stop long browsing sessions going ch… #44

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4 changes: 4 additions & 0 deletions src/Aetherphone/Apps/Aethergram/AethergramApp.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -485,6 +485,10 @@ private void DrawFeedList(Rect listRect, SocialFeedScope scope)
var snapshot = store.Feed(scope);
using (AppSurface.Begin(listRect))
{
if (ImGui.GetScrollY() < 1f)

@XeldarAlz XeldarAlz Jul 25, 2026

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Non-blocking: OnOpened does not reset feed scroll (only RefreshActiveFeed sets feedScrollTopPending) and ImGui keeps the child's scroll offset, so a user who leaves the feed scrolled down can go a long time without ever satisfying this guard. That is exactly the browse-all-day case in the issue, so the mitigation may fire less often than expected.

{
store.TrimFeed(scope, SocialFeedStore.FeedCap);
}
stories.DrawTray(theme);
if (snapshot.Length == 0)
{
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5 changes: 5 additions & 0 deletions src/Aetherphone/Apps/Chirper/ChirperApp.cs
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Expand Up @@ -279,6 +279,11 @@ private void DrawFeedList(Rect listRect, SocialFeedScope scope)
var snapshot = store.Feed(scope);
using (AppSurface.Begin(listRect))
{
if (ImGui.GetScrollY() < 1f)
{
store.TrimFeed(scope, SocialFeedStore.FeedCap);

@XeldarAlz XeldarAlz Jul 25, 2026

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Nit: stray blank line inside the block.

}
if (snapshot.Length == 0)
{
var message = store.IsLoading(scope) ? Loc.T(L.Common.Loading) :
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20 changes: 20 additions & 0 deletions src/Aetherphone/Core/Social/FeedLane.cs
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Expand Up @@ -60,6 +60,26 @@ public void ApplyMore(TPost[] incoming, string? nextCursor)
}
}

public void Trim(int max)

@XeldarAlz XeldarAlz Jul 25, 2026

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Non-blocking, answering the open question: option 1 is the right call and option 3 does not work. Per-page cursors cannot rewind a trim, because refreshes prepend to the head, so a recorded page boundary drifts deeper over the day. In the issue's own scenario (head growth from repeated app opens) the page-1 boundary ends up past the cap, and a boundary-aligned trim either refuses to fire or rewinds to a cursor from hours ago. A real rewind needs a cursor the client can derive from a post id or timestamp, which is a server change.

{
if (max <= 0)
{
return;
}

lock (gate)
{
if (items.Length <= max)

@XeldarAlz XeldarAlz Jul 25, 2026

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Non-blocking: please add coverage to FeedLaneTests.cs. Trim is pure and needs no ImGui, so keep-newest, under-cap no-op and cursor-survives-trim are three cheap tests.

{
return;
}

var trimmed = new TPost[max];
Array.Copy(items, trimmed, max);

@XeldarAlz XeldarAlz Jul 25, 2026

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Non-blocking: Trim reads and writes items under gate, but ReplacePost, ApplySavedEverywhere and RemoveAuthorEverywhere all assign lane.Items without it. A background update landing between the read and the write here is silently dropped, so a like or follow flag can revert until the next refresh. Pre-existing pattern rather than something you introduced, just widened by one more writer.

items = trimmed;
}
}

public void Clear()
{
lock (gate)
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4 changes: 4 additions & 0 deletions src/Aetherphone/Core/Social/SocialFeedStore.cs
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Expand Up @@ -105,6 +105,10 @@ private void OnSessionChanged()

public bool LoadingMore(SocialFeedScope scope) => Lane(scope).LoadingMore;

public const int FeedCap = 300;

@XeldarAlz XeldarAlz Jul 25, 2026

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Non-blocking: the cap constant lives here, but the policy that decides when to apply it (the scroll check) lives in each app's draw method, so a new social feed opts out just by forgetting a line. FeedVirtualizer is the seam all three feeds already share: give BeginFrame an optional trimmable source and the cap, the scroll guard and Velvet coverage all land in one place.


public void TrimFeed(SocialFeedScope scope, int max) => Lane(scope).Trim(max);

@XeldarAlz XeldarAlz Jul 25, 2026

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Blocking: Velvet is a third social feed with the same problem and it is not covered here. It has its own VelvetStore holding FeedLane<VelvetPostDto>[], and the same uncapped draw loop at VelvetShell.Feed.cs:68, so it keeps growing all day after this merges. The description is right that Chirper comes along for free, but Velvet does not.


private FeedLane<PostDto> Lane(SocialFeedScope scope) =>
scope == SocialFeedScope.ForYou ? forYouLane : followingLane;

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