fix: prevent loading stale profiles on realm change

[lorenzo-ranciaffi]

Pull Request Description

Fixes #8827

What does this PR change?

This PR makes sure that on realm change, profiles that are being downloaded for the previous realm, are cancelled (RemoteProfiles.TryDownloadAsync is a fire & forget) so that when they are completed, they don't get included into remoteProfiles leading to "ghost avatars".

Test Steps

1. Follow repro steps of the linked issue
2. Smoke test, everything should operate as normal (especially in terms of remote avatars across teleports between worlds and Genesis City)

Quality Checklist

• Changes have been tested locally
• Documentation has been updated (if required)
• Performance impact has been considered
• For SDK features: Test scene is included

Code Review Reference

Please review our Branch & PR Standards before submitting. It explains the automated review flow, QA/DEV approval requirements, and what each label does — especially useful for first-time contributors.

[github-actions]

Windows and Mac build successful in Unity Cloud! You can find a link to the downloadable artifact below.

Name	Link
Commit	6cbe65b
Logs	https://github.com/decentraland/unity-explorer/actions/runs/26172923799
Download Windows	https://github.com/decentraland/unity-explorer/suites/69952796118/artifacts/7115383221
Download Windows S3	https://explorer-artifacts.decentraland.org/@dcl/unity-explorer/branch/fix/8827-remove-stale-profiles/pr-22475-6cbe65b/Decentraland_windows64.zip
Download Mac	https://github.com/decentraland/unity-explorer/suites/69952796118/artifacts/7115311196
Download Mac S3	https://explorer-artifacts.decentraland.org/@dcl/unity-explorer/branch/fix/8827-remove-stale-profiles/pr-22475-6cbe65b/Decentraland_macos.zip
Built on	2026-05-20T16:16:19Z

[lorenzo-ranciaffi]

@claude review

[claude]

Claude finished @lorenzo-ranciaffi's task in 3m 22s —— View job

---

PR Review

• Read CLAUDE.md and docs/README.md
• Read changed files and diff
• Analyze and post review

---

Root-cause assessment: PASS ✅

This PR fixes the root cause. Fire-and-forget TryDownloadAsync calls issued for the previous realm completed after realm change and injected stale RemoteProfile entries into the shared list, creating ghost avatars. The fix correctly:

1. Lifts RemoteAnnouncements and RemoteProfiles instantiation out of MultiplayerPlugin.InjectToWorld() so they can be shared with the teleport pipeline.
2. Adds Reset() to both, cancelling all in-flight CTSes and clearing buffered state.
3. Calls Reset() synchronously during RemoveRemoteEntitiesTeleportOperation, before ForceRemoveAll, so no stale data survives into the new realm.
4. Adds the cts.IsCancellationRequested || !pendingProfiles.TryGetValue(...) guard in TryDownloadAsync so async continuations resuming after Reset() exit safely without writing to remoteProfiles.

All previously flagged issues (multi-line comment blocks, grammar error) have been resolved ✅.

---

Blocking issues

None.

---

Implementation notes (non-blocking)

remoteMetadata move in DynamicWorldContainer: The instantiation was correctly moved earlier (line ~448) to satisfy the new dependency ordering. All transitive dependencies (roomHub at line 435, messagePipesHub at line 446, profilesRepository at line 362) are available at that point.

finally-block / new-realm race (theoretical): After Reset() clears pendingProfiles, if a new-realm download is initiated for the same walletId with the same profileVersion before an old download's finally block runs, the old finally could remove the new entry from pendingProfiles. The new download's try guard (!pendingProfiles.TryGetValue(...)) would then cause it to return early. The avatar would simply be re-requested on the next announcement cycle. Probability is very low given the disconnect-reconnect timing between realms, and the impact is one missed frame of avatar loading — not a ghost avatar. Not worth addressing here.

Bunch<T> lifecycle: Bunch<T> wraps the underlying remoteProfiles list by reference and clears it on Dispose(). Calling Reset() mid-frame discards any buffered profiles for that frame, which is the desired behaviour during realm transition. All access is single-threaded (main thread), so no concurrency concern.

---

REVIEW_RESULT: PASS ✅
COMPLEXITY: COMPLEX
COMPLEXITY_REASON: Modifies async fire-and-forget UniTaskVoid cancellation flow, CancellationTokenSource lifecycle, and plugin/container DI wiring across 6 files.
QA_REQUIRED: YES

[github-actions]

🔍 Claude reviewed this PR and found no blocking issues, but assessed it as complex — human DEV review is still required before merging.

[m3taphysics]

PR #8834, run #26175361330

Builds: Windows change, Windows baseline, macOS change, macOS baseline

Framework 13 i7

Metric	Change	Baseline	Delta	Improvement
Samples	2700	2699
CPU average	33.3 ms	33.3 ms	-0.0 ms	0.0%	⚪
CPU 1% worst	33.4 ms	34.0 ms	-0.6 ms	1.6%	⚪
CPU 0.1% worst	33.6 ms	37.6 ms	-4.0 ms	10.6%	🟢
GPU average	7.5 ms	7.7 ms	-0.1 ms	1.8%	⚪
GPU 1% worst	19.4 ms	19.6 ms	-0.2 ms	0.9%	⚪
GPU 0.1% worst	25.5 ms	23.7 ms	1.8 ms	-7.7%	🔴

[DafGreco]

✔️ PR reviewed and approved by QA on both platforms following instructions playing both happy and un-happy path

Regressions for this ticket had been performed in order to verify that the normal flow is working as expected:

• [ ✔️] Backpack and wearables in world
• [ ✔️] Emotes in world and in backpack
• [ ✔️] Teleport with map/coordinates/Jump In
• [✔️ ] Chat and multiplayer
• [ ✔️] Profile card
• [ ✔️] Camera
• [ ✔️] Skybox
• [ ✔️] Settings

Evidence:

thread with evidence

Player (23).log