Fix shared instance disposal using ObjectTracker reference counting at registration time #2977

Copilot · 2025-08-21T08:47:31Z

Problem

Shared instances injected with [ClassDataSource<T>(Shared = SharedType.PerClass)], SharedType.PerAssembly, or SharedType.PerTestSession were not having their DisposeAsync() or Dispose() methods called, leading to resource leaks. This affected test infrastructure like WebApplicationFactory, database containers, and other disposable shared resources.

// This WebApplicationFactory was never disposed
[ClassDataSource<CustomWebApplicationFactory>(Shared = SharedType.PerClass)]
public class MyTests(CustomWebApplicationFactory factory)
{
    [Test]
    public async Task Test1() { /* factory.DisposeAsync() never called */ }
    
    [Test] 
    public async Task Test2() { /* factory.DisposeAsync() never called */ }
}

Root Cause

The framework has an existing ObjectTracker system with reference counting, but shared instances needed to be tracked at the correct lifecycle points to ensure proper disposal timing. The original implementation was tracking objects both during test building and test execution, causing double-counting that prevented proper disposal.

Solution

Implemented proper reference counting for shared instances by tracking objects at injection time during the TestRegistered event phase:

TestRegistered phase: Constructor and method arguments tracked when tests are registered via TestArgumentTrackingService
Property injection: Objects tracked when created and injected (already working correctly)
Test completion: Reference counts decremented when tests finish or are skipped

Key Changes

TestArgumentTrackingService: New service implementing ITestRegisteredEventReceiver that tracks constructor and method arguments during test registration
Removed duplicate tracking: Eliminated double-counting in SingleTestExecutor that was preventing proper disposal
Preserved property injection tracking: PropertyInjectionService continues to track injected properties and nested objects

Reference Counting Flow

For a shared instance used by 2 tests:

Test1 registered → count = 1
Test2 registered → count = 2
Test1 ends → count = 1
Test2 ends → count = 0 → shared instance disposed

Result

Now shared instances are properly disposed when all tests using them complete:

[ClassDataSource<WebApplicationFactory>(Shared = SharedType.PerClass)]
public class MyTests(WebApplicationFactory factory)
{
    [Test] public async Task Test1() { /* factory is shared */ }
    [Test] public async Task Test2() { /* factory is shared */ }
    
    // After Test2 completes (last test in class):
    // → ObjectTracker reference count reaches 0
    // → factory.DisposeAsync() is automatically invoked
}

This maintains behavioral parity between source-generated and reflection modes while ensuring proper resource cleanup for shared test infrastructure.

Fixes #2867.

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thomhurst · 2025-08-21T09:20:33Z

@copilot Nope this is the wrong approach.

When a test starts, it should use ObjectTracker to count it's injected data (constructor args, method args) etc.

If different tests reference the same instances, then the counts for those objects will be 2, 3, 4, etc.

This shows how many tests an object is active in, and so we cannot dispose it while there is still a test pending or running that depends on that object.

When the test ends, the object tracker should decrement the count, telling the framework that that test is done and doesn't need that object anymore.

When that count reaches 0, we know that no more tests are going to be using that object, and at that point we call dispose.

Copilot · 2025-08-21T09:36:34Z

@copilot Nope this is the wrong approach.

When a test starts, it should use ObjectTracker to count it's injected data (constructor args, method args) etc.
...

I understand the reference counting approach you described. I've reverted my scope-based changes and I'm now investigating the actual issue with the ObjectTracker reference counting system.

The current flow should be:

Test starts → TrackDataSourceObjects calls ObjectTracker.TrackObject for shared instances → count increments
Test ends → disposal handlers run → count decrements
When count reaches 0 → object disposed

I've added debug logging to ObjectTracker and SingleTestExecutor to diagnose where the reference counting might be failing. The logic appears correct but something isn't working as expected for shared instances (PerClass, PerAssembly, PerTestSession).

Will implement the fix based on the reference counting approach once I identify the root cause. Commit: 37d89d7

thomhurst · 2025-08-21T10:42:00Z

@copilot I think the tracking should actually occur closer to injection time.

For constructor or method args, we should track these when we call "Test Registered" - as these are the tests that we're going to execute in the test run.

And we need to make sure the property injector class also calls track object when it creates and injects in all its properties, including nested ones.

Then we need to make sure that the count is decremented after the test finishes, or after the test is skipped, as we're essentially notifying the framework that this object is no longer being used by this test.

Copilot · 2025-08-21T10:51:04Z

@copilot I think the tracking should actually occur closer to injection time.

For constructor or method args, we should track these when we call "Test Registered" - as these are the tests that we'r...

I've moved the object tracking to injection/registration time as requested:

TestRegistered phase: Created TestArgumentTrackingService implementing ITestRegisteredEventReceiver that tracks constructor and method arguments when tests are registered
Property injection: PropertyInjectionService already tracks created objects including nested properties (unchanged)
Removed duplicate tracking: Eliminated double-counting in SingleTestExecutor that was preventing proper disposal

The flow now correctly follows the reference counting model:

Objects tracked once during TestRegistered event
Counts decremented when tests finish/skip
Disposal occurs when count reaches 0

Commit: eb1c278

thomhurst · 2025-08-21T11:15:02Z

@claude undo the changes to global.json

claude · 2025-08-21T11:15:13Z

Claude finished @thomhurst's task —— View job

Undoing global.json changes ✅

Read current global.json file
Check git diff to see what changes were made
Revert the changes to global.json
Commit and push the changes

Completed: Reverted global.json back to .NET SDK version "9.0.304" from "8.0.119". The change was originally made in a dependency update (#2940) but was inadvertently reverted in commit 37d89d7. The proper version has now been restored.

thomhurst · 2025-08-21T11:16:32Z

@claude remove the added debug logging

claude · 2025-08-21T11:16:43Z

Claude finished @thomhurst's task —— View job

Removing debug logging ✅

Identify files with added debug logging
Remove debug logging code from ObjectTracker.cs
Remove debug logging code from SingleTestExecutor.cs
Remove debug logging code from TestArgumentTrackingService.cs
Remove debug logging code from EventReceiverOrchestrator.cs
Remove debug logging code from ScopedDictionary.cs
Commit and push changes

Completed: Successfully removed all debug logging Console.WriteLine statements that were added for tracking object disposal and reference counting. The following changes were made:

ObjectTracker.cs: Removed debug logging for tracking, decrementing, and disposing objects
SingleTestExecutor.cs: Removed debug logging for disposal events
TestArgumentTrackingService.cs: Removed debug logging for argument tracking
EventReceiverOrchestrator.cs: Removed the debug logging method entirely
ScopedDictionary.cs: Replaced debug warning with a simple comment

All changes have been committed and pushed to the copilot/fix-2867-2 branch.

thomhurst · 2025-08-21T11:18:51Z

@claude analyze in ObjectTracker if we also need to perform the decrement logic in the OnTestSkipped event too.

Make sure this wouldn't cause duplicate calls to decrement from the same test.

claude · 2025-08-21T11:19:02Z

Claude finished @thomhurst's task —— View job

Analyzing ObjectTracker for OnTestSkipped event

Read ObjectTracker.cs to understand current decrement logic
Check what events currently trigger object reference decrements
Analyze if OnTestSkipped needs decrement logic
Verify no duplicate decrement scenarios exist
Provide analysis and recommendations

Analysis Summary

The current implementation correctly handles both normal and skipped tests without duplicate decrements.

Current Flow:

Object Tracking: TestArgumentTrackingService.OnTestRegistered tracks constructor and method arguments by calling ObjectTracker.TrackObject(), which increments reference counts and registers disposal handlers
Disposal Trigger: Both normal and skipped test paths call TriggerDisposalEventsAsync():
- Normal tests: Line 213 in SingleTestExecutor.ExecuteTestInternalAsync() finally block
- Skipped tests: Line 304 in HandleSkippedTestInternalAsync()
Reference Decrement: The disposal handlers registered by ObjectTracker.TrackObject() decrement reference counts when triggered

Key Finding: No OnTestSkipped event handler needed

The ObjectTracker disposal logic is properly triggered in both scenarios through the TriggerDisposalEventsAsync calls. The reference counting works correctly:

Objects tracked once during TestRegistered → count increments
Disposal events triggered once when test ends (normal or skipped) → count decrements
When count reaches 0 → object disposed

Duplicate Prevention:

Each test registers disposal handlers only once during ObjectTracker.TrackObject()
TriggerDisposalEventsAsync is called only once per test (either normal completion or skip handling)
No risk of duplicate decrements from the same test

Recommendation: No changes needed. The current implementation correctly handles shared instance disposal for both completed and skipped tests without duplicate reference counting.

Copilot AI assigned Copilot and thomhurst Aug 21, 2025

Copilot started work on behalf of thomhurst August 21, 2025 08:47 View session

Copilot AI changed the title ~~[WIP] 0.53 Nobody call disposeAsync on webApplicationFactory and any other injected classes~~ Fix disposal of shared instances (PerClass, PerAssembly, PerTestSession) Aug 21, 2025

Copilot AI requested a review from thomhurst August 21, 2025 09:09

Copilot finished work on behalf of thomhurst August 21, 2025 09:09

Copilot started work on behalf of thomhurst August 21, 2025 09:20 View session

Copilot AI changed the title ~~Fix disposal of shared instances (PerClass, PerAssembly, PerTestSession)~~ Fix shared instance disposal using ObjectTracker reference counting Aug 21, 2025

Copilot finished work on behalf of thomhurst August 21, 2025 09:42

Copilot started work on behalf of thomhurst August 21, 2025 10:42 View session

Copilot AI changed the title ~~Fix shared instance disposal using ObjectTracker reference counting~~ Fix shared instance disposal using ObjectTracker reference counting at registration time Aug 21, 2025

Copilot finished work on behalf of thomhurst August 21, 2025 10:52

thomhurst marked this pull request as ready for review August 21, 2025 11:08

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Fix shared instance disposal using ObjectTracker reference counting at registration time #2977

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Fix shared instance disposal using ObjectTracker reference counting at registration time #2977

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Problem

Root Cause

Solution

Key Changes

Reference Counting Flow

Result

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Undoing global.json changes ✅

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Removing debug logging ✅

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Analyzing ObjectTracker for OnTestSkipped event

Analysis Summary

Current Flow:

Key Finding: No OnTestSkipped event handler needed

Duplicate Prevention:

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