[leak-fix] Fix IndicatorView.ItemsSource memory leak (Fixes #35775)

[kubaflo]

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Note

🤖 AI-generated PR. This fix and its regression test were produced by an AI-driven memory-leak workflow and verified locally. Please review carefully before merging.

Fixes #35775

The leak

IndicatorView.ItemsSource subscribed the IndicatorView to the assigned collection with a plain, non-weak delegate — collection.CollectionChanged += OnCollectionChanged in ResetItemsSource (src/Controls/src/Core/IndicatorView/IndicatorView.cs). Because OnCollectionChanged is an instance method, the delegate Target is the IndicatorView, and the only -= ran when ItemsSource itself changed — never on unload/navigation. The documented usage is to bind the same long-lived collection as a CarouselView, so that shared ObservableCollection strongly retained every IndicatorView attached to it (and its visual subtree / behaviors) for the collection's whole lifetime.

The fix

Replace the plain subscription with a WeakNotifyCollectionChangedProxy stored in a field, and add a finalizer that calls Unsubscribe(). This mirrors the existing BindableLayoutController pattern (src/Controls/src/Core/BindableLayout/BindableLayout.cs): the collection now references only the proxy, which holds the IndicatorView weakly, so it can be collected once unreferenced; the handler delegate is kept alive in a field while the IndicatorView lives, and the finalizer tears the proxy down from the still-alive collection.

Regression test

IndicatorViewTests.IndicatorViewItemsSourceDoesNotLeak in src/Controls/tests/Core.UnitTests/IndicatorViewLayoutTests.cs: assigns a long-lived ObservableCollection to a new IndicatorView, drops the only strong reference, forces GC, and asserts the view is collected via WeakReference.WaitForCollect().

Verified locally against this PR's base (main), Controls.Core.UnitTests:

State	Result
Without fix (current main)	❌ FAILS — IndicatorView should not be alive!
With fix	✅ Passed IndicatorViewItemsSourceDoesNotLeak

Scope

Managed cross-platform change → all platforms. The only public-API addition is the finalizer, recorded in the per-TFM PublicAPI.Unshipped.txt files.

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 36252

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 36252"

[MauiBot]

Expert Review — 1 findings

See inline comments for details.

[MauiBot]

🔍 AI-Generated Review (multi-model)

[moderate] Public API Surface — This adds a duplicate StructuredItemsViewController2<TItemsView>.UpdateFlowDirection() baseline entry; the same signature is already present in this file at line 6. The same accidental duplicate appears in net-maccatalyst/PublicAPI.Unshipped.txt. Please remove these unrelated duplicates and leave only the IndicatorView.~IndicatorView() entries for this fix.

[MauiBot]

AI Review Summary

@kubaflo — new AI review results are available based on this last commit: 9e5729f. To request a fresh review after new comments or commits, comment /review rerun.

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🗂️ Review Sessions — click to expand

🚦 Gate — Test Before & After Fix

Gate Result: ✅ PASSED

Platform: ANDROID · Base: main · Merge base: 9a71eb6e

Test	Without Fix (expect FAIL)	With Fix (expect PASS)
🧪 IndicatorViewTests IndicatorViewTests	✅ FAIL — 155s	✅ PASS — 125s

🔴 Without fix — 🧪 IndicatorViewTests: FAIL ✅ · 155s

  Determining projects to restore...
  Restored /home/vsts/work/1/s/src/Controls/tests/Core.UnitTests/Controls.Core.UnitTests.csproj (in 6.47 sec).
  Restored /home/vsts/work/1/s/src/TestUtils/src/TestUtils/TestUtils.csproj (in 102 ms).
  Restored /home/vsts/work/1/s/src/Graphics/src/Graphics/Graphics.csproj (in 257 ms).
  Restored /home/vsts/work/1/s/src/Essentials/src/Essentials.csproj (in 255 ms).
  Restored /home/vsts/work/1/s/src/Controls/src/Xaml/Controls.Xaml.csproj (in 10.29 sec).
  Restored /home/vsts/work/1/s/src/Core/src/Core.csproj (in 120 ms).
  Restored /home/vsts/work/1/s/src/Controls/src/Core/Controls.Core.csproj (in 29 ms).
  Restored /home/vsts/work/1/s/src/Core/maps/src/Maps.csproj (in 837 ms).
  Restored /home/vsts/work/1/s/src/Controls/Maps/src/Controls.Maps.csproj (in 731 ms).
  1 of 10 projects are up-to-date for restore.
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Graphics -> /home/vsts/work/1/s/artifacts/bin/Graphics/Debug/net10.0/Microsoft.Maui.Graphics.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Essentials -> /home/vsts/work/1/s/artifacts/bin/Essentials/Debug/net10.0/Microsoft.Maui.Essentials.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Core -> /home/vsts/work/1/s/artifacts/bin/Core/Debug/net10.0/Microsoft.Maui.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Maps -> /home/vsts/work/1/s/artifacts/bin/Maps/Debug/net10.0/Microsoft.Maui.Maps.dll
  Controls.BindingSourceGen -> /home/vsts/work/1/s/artifacts/bin/Controls.BindingSourceGen/Debug/netstandard2.0/Microsoft.Maui.Controls.BindingSourceGen.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Controls.Core -> /home/vsts/work/1/s/artifacts/bin/Controls.Core/Debug/net10.0/Microsoft.Maui.Controls.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Controls.Maps -> /home/vsts/work/1/s/artifacts/bin/Controls.Maps/Debug/net10.0/Microsoft.Maui.Controls.Maps.dll
  Controls.Xaml -> /home/vsts/work/1/s/artifacts/bin/Controls.Xaml/Debug/net10.0/Microsoft.Maui.Controls.Xaml.dll
  TestUtils -> /home/vsts/work/1/s/artifacts/bin/TestUtils/Debug/netstandard2.0/Microsoft.Maui.TestUtils.dll
  Controls.Core.UnitTests -> /home/vsts/work/1/s/artifacts/bin/Controls.Core.UnitTests/Debug/net10.0/Microsoft.Maui.Controls.Core.UnitTests.dll
Test run for /home/vsts/work/1/s/artifacts/bin/Controls.Core.UnitTests/Debug/net10.0/Microsoft.Maui.Controls.Core.UnitTests.dll (.NETCoreApp,Version=v10.0)
VSTest version 18.0.1 (x64)

Starting test execution, please wait...
A total of 1 test files matched the specified pattern.
[xUnit.net 00:00:00.00] xUnit.net VSTest Adapter v2.8.2+699d445a1a (64-bit .NET 10.0.0)
[xUnit.net 00:00:00.27]   Discovering: Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:02.31]   Discovered:  Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:02.34]   Starting:    Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:04.02]     IndicatorViewItemsSourceDoesNotLeak [FAIL]
[xUnit.net 00:00:04.03]       IndicatorView should not be alive!
[xUnit.net 00:00:04.03]       Stack Trace:
[xUnit.net 00:00:04.03]         /_/src/Controls/tests/Core.UnitTests/IndicatorViewLayoutTests.cs(86,0): at Microsoft.Maui.Controls.Core.UnitTests.IndicatorViewTests.IndicatorViewItemsSourceDoesNotLeak()
[xUnit.net 00:00:04.03]         --- End of stack trace from previous location ---
  Passed IndicatorLayout_ShouldBeRemovedWhenIndicatorTemplateIsNulled [93 ms]
  Passed IndicatorStackLayoutNoItems_ResetIndicators_ShouldHaveNoChildren [9 ms]
  Passed IndicatorStackLayout_ResetIndicatorCount_ShouldBindChildren(oldCount: 1, expected: 2) [15 ms]
  Passed IndicatorStackLayout_ResetIndicatorCount_ShouldBindChildren(oldCount: -2, expected: 2) [1 ms]
  Passed IndicatorStackLayout_ResetIndicatorCount_ShouldBindChildren(oldCount: 0, expected: 2) [< 1 ms]
[xUnit.net 00:00:04.05]   Finished:    Microsoft.Maui.Controls.Core.UnitTests
  Failed IndicatorViewItemsSourceDoesNotLeak [1 s]
  Error Message:
   IndicatorView should not be alive!
  Stack Trace:
     at Microsoft.Maui.Controls.Core.UnitTests.IndicatorViewTests.IndicatorViewItemsSourceDoesNotLeak() in /_/src/Controls/tests/Core.UnitTests/IndicatorViewLayoutTests.cs:line 86
--- End of stack trace from previous location ---
  Passed IndicatorStackLayoutWithItems_ResetIndicators_ShouldBindChildren [7 ms]

Test Run Failed.
Total tests: 7
     Passed: 6
     Failed: 1
 Total time: 4.8283 Seconds

🟢 With fix — 🧪 IndicatorViewTests: PASS ✅ · 125s

  Determining projects to restore...
  All projects are up-to-date for restore.
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Graphics -> /home/vsts/work/1/s/artifacts/bin/Graphics/Debug/net10.0/Microsoft.Maui.Graphics.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Essentials -> /home/vsts/work/1/s/artifacts/bin/Essentials/Debug/net10.0/Microsoft.Maui.Essentials.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Core -> /home/vsts/work/1/s/artifacts/bin/Core/Debug/net10.0/Microsoft.Maui.dll
  Controls.BindingSourceGen -> /home/vsts/work/1/s/artifacts/bin/Controls.BindingSourceGen/Debug/netstandard2.0/Microsoft.Maui.Controls.BindingSourceGen.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Maps -> /home/vsts/work/1/s/artifacts/bin/Maps/Debug/net10.0/Microsoft.Maui.Maps.dll
  Controls.Core -> /home/vsts/work/1/s/artifacts/bin/Controls.Core/Debug/net10.0/Microsoft.Maui.Controls.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Controls.Xaml -> /home/vsts/work/1/s/artifacts/bin/Controls.Xaml/Debug/net10.0/Microsoft.Maui.Controls.Xaml.dll
  ##vso[build.updatebuildnumber]10.0.90-ci+azdo.14599358
  Controls.Maps -> /home/vsts/work/1/s/artifacts/bin/Controls.Maps/Debug/net10.0/Microsoft.Maui.Controls.Maps.dll
  TestUtils -> /home/vsts/work/1/s/artifacts/bin/TestUtils/Debug/netstandard2.0/Microsoft.Maui.TestUtils.dll
  Controls.Core.UnitTests -> /home/vsts/work/1/s/artifacts/bin/Controls.Core.UnitTests/Debug/net10.0/Microsoft.Maui.Controls.Core.UnitTests.dll
Test run for /home/vsts/work/1/s/artifacts/bin/Controls.Core.UnitTests/Debug/net10.0/Microsoft.Maui.Controls.Core.UnitTests.dll (.NETCoreApp,Version=v10.0)
VSTest version 18.0.1 (x64)

Starting test execution, please wait...
A total of 1 test files matched the specified pattern.
[xUnit.net 00:00:00.00] xUnit.net VSTest Adapter v2.8.2+699d445a1a (64-bit .NET 10.0.0)
[xUnit.net 00:00:00.25]   Discovering: Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:02.47]   Discovered:  Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:02.49]   Starting:    Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:02.77]   Finished:    Microsoft.Maui.Controls.Core.UnitTests
  Passed IndicatorLayout_ShouldBeRemovedWhenIndicatorTemplateIsNulled [90 ms]
  Passed IndicatorStackLayoutNoItems_ResetIndicators_ShouldHaveNoChildren [9 ms]
  Passed IndicatorStackLayout_ResetIndicatorCount_ShouldBindChildren(oldCount: 1, expected: 2) [16 ms]
  Passed IndicatorStackLayout_ResetIndicatorCount_ShouldBindChildren(oldCount: -2, expected: 2) [1 ms]
  Passed IndicatorStackLayout_ResetIndicatorCount_ShouldBindChildren(oldCount: 0, expected: 2) [1 ms]
  Passed IndicatorViewItemsSourceDoesNotLeak [55 ms]
  Passed IndicatorStackLayoutWithItems_ResetIndicators_ShouldBindChildren [1 ms]

Test Run Successful.
Total tests: 7
     Passed: 7
 Total time: 3.7468 Seconds

📁 Fix files reverted (8 files)

• src/Controls/src/Core/IndicatorView/IndicatorView.cs
• src/Controls/src/Core/PublicAPI/net-android/PublicAPI.Unshipped.txt
• src/Controls/src/Core/PublicAPI/net-ios/PublicAPI.Unshipped.txt
• src/Controls/src/Core/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txt
• src/Controls/src/Core/PublicAPI/net-tizen/PublicAPI.Unshipped.txt
• src/Controls/src/Core/PublicAPI/net-windows/PublicAPI.Unshipped.txt
• src/Controls/src/Core/PublicAPI/net/PublicAPI.Unshipped.txt
• src/Controls/src/Core/PublicAPI/netstandard/PublicAPI.Unshipped.txt

---

📱 UI Tests — CarouselView,IndicatorView

Detected UI test categories: CarouselView,IndicatorView

[!WARNING]
No UI test results were produced for the detected categories. The platform-pool run
returned no results — most often because the PR build failed (see the Gate section) or
the deep UI test stage was skipped. Fix the build/gate issues and comment /review rerun
to get UI test results.

---

📋 Pre-Flight — Context & Validation

Issue: #35775 - IndicatorView leaks when CarouselView.IndicatorView is bound to a shared ObservableCollection
PR: #36252 - [leak-fix] Fix IndicatorView.ItemsSource memory leak (Fixes #35775)
Platforms Affected: Android, iOS, macOS/Mac Catalyst; managed Controls change applies cross-platform
Files Changed: 8 implementation/API, 1 test

Key Findings

• Root cause: IndicatorView.ItemsSource subscribed to INotifyCollectionChanged.CollectionChanged with an instance handler; a rooted shared ObservableCollection<T> could strongly retain discarded IndicatorView instances.
• PR fix replaces the strong subscription with WeakNotifyCollectionChangedProxy, keeps the handler delegate alive in an instance field, and adds a finalizer to unsubscribe the proxy.
• Regression coverage is a Controls unit memory test (IndicatorViewItemsSourceDoesNotLeak); no UI test category is required beyond possible IndicatorView impact tracking.

Code Review Summary

Verdict: NEEDS_DISCUSSION
Confidence: low
Errors: 0 | Warnings: 0 | Suggestions: 0

Key code review findings:

• ℹ No code-level issues found. Confidence is capped because gh pr checks --required is unavailable without authentication and public check state was pending/undetermined.

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #36252	Replace direct CollectionChanged subscription with WeakNotifyCollectionChangedProxy; add finalizer cleanup and PublicAPI entries	✅ PASSED (Gate)	IndicatorView.cs, PublicAPI files, unit test	Original PR

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🔬 Code Review — Deep Analysis

Code Review — PR #36252

Independent Assessment

What this changes: Replaces IndicatorView.ItemsSource's strong CollectionChanged subscription with WeakNotifyCollectionChangedProxy, stores the handler delegate strongly on the IndicatorView, and adds a finalizer to unsubscribe the proxy. Adds a memory regression test and PublicAPI entries for the finalizer.

Inferred motivation: Prevent long-lived observable item sources from retaining discarded IndicatorView instances through event subscriptions.

Reconciliation with PR Narrative

Author claims: Fixes IndicatorView.ItemsSource memory leak for shared/rooted ObservableCollection, following the existing BindableLayoutController weak-proxy pattern, with regression coverage.

Agreement/disagreement: Agrees. The code matches the described root cause and mirrors the established WeakNotifyCollectionChangedProxy usage pattern in BindableLayoutController.

Prior Review Reconciliation

No prior ❌ Error findings found. Checked top-level reviews, inline review comments, and issue comments via public GitHub API. Existing MauiBot reviews reported no error-level findings; ❌ FAILS references were baseline test-verification notes, not unresolved review findings.

Blast Radius Assessment

• Runs for all instances: Only IndicatorView instances whose ItemsSource implements INotifyCollectionChanged.
• Startup impact: No.
• Static/shared state: No new static/shared state.
• Lifecycle impact: Adds a finalizer and weak event proxy lifecycle for observable ItemsSource.

CI Status

• Required-check result: gh pr checks --required unavailable due missing auth; public commit checks show multiple maui-pr checks still in_progress / pending.
• Classification: undetermined / pending.
• Action taken: Invoked azdo-build-investigator; required ci-analysis skill was unavailable. Confidence capped low; verdict cannot be LGTM while CI is pending/undetermined.

Findings

No ❌ Error findings.

No ⚠️ Warning findings.

No 💡 Suggestion findings.

Failure-Mode Probing

• Non-observable ItemsSource: No proxy subscription is created; reset still recomputes count safely.
• Reassigning observable sources: Old observable source causes _collectionChangedProxy.Unsubscribe() before subscribing the new source.
• ItemsSource = null: OnCollectionChanged(null, Reset) sets Count to 0 without null dereference.
• Delegate lifetime: _collectionChangedEventHandler keeps the handler alive while the view lives; proxy holds it weakly to avoid rooting the view.
• Post-GC collection changes: If handler target is gone, proxy unsubscribes itself on the next event; finalizer also unsubscribes.

Verdict: NEEDS_DISCUSSION

Confidence: low, due pending/undetermined CI per skill rules.
Summary: The implementation looks correct and follows an existing MAUI weak-event pattern. I found no code-level issues, but CI has not been verified as passing, so this cannot be marked LGTM yet.

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🛠️ Fix — Analysis & Comparison

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
1	try-fix-1	Lifecycle-scoped strong subscription via OnParentSet; subscribe only while parented and resync on reparent	✅ PASS	IndicatorView.cs, PublicAPI files	Not selected: changes unparented update semantics and still adds API entries for the protected override.
2	try-fix-2	Private static weak listener registry keyed by collection with static event handler and weak IndicatorView references	✅ PASS	IndicatorView.cs	Not selected: avoids finalizer/API entries, but introduces bespoke static state, locking, and opportunistic cleanup; higher maintenance risk than existing MAUI weak proxy.
PR	PR #36252	Use existing WeakNotifyCollectionChangedProxy, retain handler delegate in field, and finalizer-unsubscribe proxy	✅ PASSED (Gate)	IndicatorView.cs, PublicAPI files, unit test	Selected: preserves existing semantics and reuses established MAUI pattern.

Cross-Pollination

Model/Reviewer	Round	New Ideas?	Details
maui-expert-reviewer	1	Yes	Suggested lifecycle-scoped strong subscription; implemented as try-fix-1.
maui-expert-reviewer	2	Yes	Suggested static weak listener registry; implemented as try-fix-2.
maui-expert-reviewer	3	No	Reported design space exhausted: weak proxy, lifecycle subscription, static registry, no-subscription binding, and manual cleanup/API variants were either already tested or inferior/trivial.

Exhausted: Yes
Selected Fix: PR's fix — it is the best option among tested candidates because it preserves IndicatorView.ItemsSource collection-change behavior, avoids bespoke global/static listener state, and follows the existing WeakNotifyCollectionChangedProxy pattern already used in MAUI Controls.

Candidate Details

try-fix-1

• Approach: Subscribe strongly only while the IndicatorView has a parent; unsubscribe when unparented; resync on reparent.
• Test: dotnet test src/Controls/tests/Core.UnitTests/Controls.Core.UnitTests.csproj --filter "FullyQualifiedName~IndicatorView" --logger "console;verbosity=minimal"
• Result: ✅ PASS after adding required PublicAPI entries for override IndicatorView.OnParentSet().
• Failure/selection analysis: Not selected because it changes behavior for unparented observable ItemsSource instances and still requires public API entries.
• Diff: CustomAgentLogsTmp/PRState/36252/PRAgent/try-fix-1/fix.diff
• Test output: CustomAgentLogsTmp/PRState/36252/PRAgent/try-fix-1/test-output.log

try-fix-2

• Approach: Use a private static weak listener registry (ConditionalWeakTable) and static collection-change handler to avoid collection -> IndicatorView strong references.
• Test: dotnet test src/Controls/tests/Core.UnitTests/Controls.Core.UnitTests.csproj --filter "FullyQualifiedName~IndicatorView" --logger "console;verbosity=minimal"
• Result: ✅ PASS.
• Failure/selection analysis: Not selected because the bespoke static registry is more complex and riskier than reusing MAUI's existing weak-event proxy pattern; dead listener cleanup is opportunistic.
• Diff: CustomAgentLogsTmp/PRState/36252/PRAgent/try-fix-2/fix.diff
• Test output: CustomAgentLogsTmp/PRState/36252/PRAgent/try-fix-2/test-output.log

---

📝 Recommended PR Title & Description

Assessment: ✏️ Recommend updating — the implementation is accurate, but the description should mention the reviewer cleanup that removes unrelated duplicate iOS/MacCatalyst PublicAPI entries.

Recommended title

[Controls] IndicatorView: Fix ItemsSource memory leak (Fixes #35775)

Recommended description

> [!NOTE]
> 🤖 **AI-generated PR.** This fix and its regression test were produced by an AI-driven memory-leak workflow and verified locally. Please review carefully before merging.

Fixes #35775

### The leak

`IndicatorView.ItemsSource` subscribed the `IndicatorView` to the assigned collection with a plain, non-weak delegate — `collection.CollectionChanged += OnCollectionChanged` in `ResetItemsSource` (`src/Controls/src/Core/IndicatorView/IndicatorView.cs`). Because `OnCollectionChanged` is an instance method, the delegate `Target` is the `IndicatorView`, and the only `-=` ran when `ItemsSource` itself changed — never on unload/navigation. The documented usage is to bind the **same long-lived collection as a `CarouselView`**, so that shared `ObservableCollection` strongly retained every `IndicatorView` attached to it (and its visual subtree / behaviors) for the collection's whole lifetime.

### The fix

Replace the plain subscription with a `WeakNotifyCollectionChangedProxy` stored in a field, and add a finalizer that calls `Unsubscribe()`. This mirrors the **existing `BindableLayoutController` pattern** (`src/Controls/src/Core/BindableLayout/BindableLayout.cs`): the collection now references only the proxy, which holds the `IndicatorView` weakly, so it can be collected once unreferenced; the handler delegate is kept alive in a field while the `IndicatorView` lives, and the finalizer tears the proxy down from the still-alive collection.

The final candidate also removes unrelated duplicate `StructuredItemsViewController2<TItemsView>.UpdateFlowDirection()` entries from the iOS and MacCatalyst `PublicAPI.Unshipped.txt` files, leaving only the intended `IndicatorView.~IndicatorView()` API baseline additions for this fix.

### Regression test

`IndicatorViewTests.IndicatorViewItemsSourceDoesNotLeak` in `src/Controls/tests/Core.UnitTests/IndicatorViewLayoutTests.cs`: assigns a long-lived `ObservableCollection` to a new `IndicatorView`, drops the only strong reference, forces GC, and asserts the view is collected via `WeakReference.WaitForCollect()`.

**Verified locally against this PR's base (`main`), `Controls.Core.UnitTests`:**

| State | Result |
|---|---|
| Without fix (current `main`) | ❌ FAILS — `IndicatorView should not be alive!` |
| With fix | ✅ `Passed IndicatorViewItemsSourceDoesNotLeak` |

### Scope

Managed cross-platform Controls change → all platforms. The only intended public-API addition is the finalizer, recorded in the per-TFM `PublicAPI.Unshipped.txt` files.

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🏁 Report — Final Recommendation

Comparative Analysis — PR #36252

Candidates evaluated

Candidate	Approach	Regression result	Rank
pr-plus-reviewer	PR weak-proxy fix plus removal of duplicate unrelated iOS/MacCatalyst PublicAPI entries	✅ PASS	1
pr	Replace direct CollectionChanged subscription with WeakNotifyCollectionChangedProxy, retain delegate, finalizer-unsubscribe proxy	✅ PASS	2
try-fix-2	Static weak listener registry keyed by collection with weak IndicatorView references	✅ PASS	3
try-fix-1	Subscribe strongly only while parented; unsubscribe on unparent	✅ PASS	4

Analysis

pr-plus-reviewer is the best candidate. It preserves the PR's core weak-proxy implementation, which fixes the collection-to-IndicatorView strong reference cycle without changing ItemsSource update semantics, and it applies the expert reviewer's concrete cleanup by removing duplicate unrelated PublicAPI entries from the iOS and MacCatalyst API baselines.

The raw pr candidate has the same correct leak fix and passing regression result, but it leaves accidental duplicate StructuredItemsViewController2<TItemsView>.UpdateFlowDirection() entries in two PublicAPI files. That is unrelated to the IndicatorView leak fix and should not ship as part of this PR.

try-fix-2 also passes and avoids finalizer/PublicAPI additions, but it introduces a bespoke static registry, locking, listener pruning, and opportunistic cleanup. That is a broader maintenance surface than the existing MAUI WeakNotifyCollectionChangedProxy pattern already documented and used in Controls.

try-fix-1 passes but changes behavior: an unparented IndicatorView with an observable ItemsSource stops receiving collection updates until it is parented again. It also still requires PublicAPI entries for the protected OnParentSet() override. Because all candidates passed regression tests, ranking is determined by correctness, semantic preservation, and maintenance risk.

Winner

Winner: pr-plus-reviewer

The winning fix is the PR implementation with the expert reviewer cleanup applied. It fixes the leak with the established weak-event proxy pattern, preserves existing ItemsSource behavior, avoids new global/static listener state, and removes unrelated duplicate PublicAPI baseline entries.

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🧭 Next Steps — review latest findings

No alternative fix was selected for this run. Review the session findings and CI results before merging.