Memory leak after configuration disposal from PhysicalFileProvider

[MaceWindu]

Description

When application creates many short-living configuration roots, which use files it results in memory leaks around FileSystemWatcher class (in our case we setup test environment for each test and it leads to memory/performance issues as we have around 100k tests).

I've checked code and see that while ConfigurationRoot.Dispose disposes IConfigurationProvider instances, FileConfigurationProvider.Dispose disposes only _changeTokenRegistration and file (folder actually) watch infrastructure in FileConfigurationSource is never disposed.

Reproduction Steps

internal class Program
	{
		static void Main()
		{
			const int iterations = int.MaxValue;

			for (var i = 0; i < iterations; i++)
			{
				Test();
			}
		}

		static void Test()
		{
			var config = new ConfigurationBuilder().AddXmlFile("settings.xml", false, true).Build();

			(config as IDisposable)?.Dispose();
		}
	}

Expected behavior

No memory leaks

Actual behavior

Memory leaks

We need to support two runtimes currently, so results are for .NET7 and NET48

.NET 7 runtime after ~78k iterations

where byte[] instances are

In NETFX 4.8 situation is even worse (expected, as it doesn't have all improvements to file watcher related code)

Regression?

Nope

Known Workarounds

passing external PhysicalFileProvider instance and dispose it explicitly fixes leak completely:

using var fileProvider = new PhysicalFileProvider(AppContext.BaseDirectory);
using var config = new ConfigurationBuilder().AddXmlFile(fileProvider, "settings.xml", false, true).Build() as IDisposable;

Configuration

No response

Other information

No response

[ghost]

Tagging subscribers to this area: @dotnet/area-extensions-configuration
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

When application creates many short-living configuration roots, which use files it results in memory leaks around FileSystemWatcher class (in our case we setup test environment for each test and it leads to memory/performance issues as we have around 100k tests).

I've checked code and see that while ConfigurationRoot.Dispose disposes IConfigurationProvider instances, FileConfigurationProvider.Dispose disposes only _changeTokenRegistration and file (folder actually) watch infrastructure in FileConfigurationSource is never disposed.

Reproduction Steps

internal class Program
	{
		static void Main()
		{
			const int iterations = int.MaxValue;

			for (var i = 0; i < iterations; i++)
			{
				Test();
			}
		}

		static void Test()
		{
			var config = new ConfigurationBuilder().AddXmlFile("settings.xml", false, true).Build();

			(config as IDisposable)?.Dispose();
		}
	}

Expected behavior

No memory leaks

Actual behavior

Memory leaks

We need to support two runtimes currently, so results are for .NET7 and NET48

.NET 7 runtime after ~78k iterations

where byte[] instances are

In NETFX 4.8 situation is even worse (expected, as it doesn't have all improvements to file watcher related code)

Regression?

Nope

Known Workarounds

passing external PhysicalFileProvider instance and dispose it explicitly fixes leak completely:

using var fileProvider = new PhysicalFileProvider(AppContext.BaseDirectory);
using var config = new ConfigurationBuilder().AddXmlFile(fileProvider, "settings.xml", false, true).Build() as IDisposable;

Configuration

No response

Other information

No response

Author:	MaceWindu
Assignees:	-
Labels:	untriaged, area-Extensions-Configuration
Milestone:	-

[ghost]

Tagging subscribers to this area: @dotnet/area-extensions-filesystem
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

When application creates many short-living configuration roots, which use files it results in memory leaks around FileSystemWatcher class (in our case we setup test environment for each test and it leads to memory/performance issues as we have around 100k tests).

I've checked code and see that while ConfigurationRoot.Dispose disposes IConfigurationProvider instances, FileConfigurationProvider.Dispose disposes only _changeTokenRegistration and file (folder actually) watch infrastructure in FileConfigurationSource is never disposed.

Reproduction Steps

internal class Program
	{
		static void Main()
		{
			const int iterations = int.MaxValue;

			for (var i = 0; i < iterations; i++)
			{
				Test();
			}
		}

		static void Test()
		{
			var config = new ConfigurationBuilder().AddXmlFile("settings.xml", false, true).Build();

			(config as IDisposable)?.Dispose();
		}
	}

Expected behavior

No memory leaks

Actual behavior

Memory leaks

We need to support two runtimes currently, so results are for .NET7 and NET48

.NET 7 runtime after ~78k iterations

where byte[] instances are

In NETFX 4.8 situation is even worse (expected, as it doesn't have all improvements to file watcher related code)

Regression?

Nope

Known Workarounds

passing external PhysicalFileProvider instance and dispose it explicitly fixes leak completely:

using var fileProvider = new PhysicalFileProvider(AppContext.BaseDirectory);
using var config = new ConfigurationBuilder().AddXmlFile(fileProvider, "settings.xml", false, true).Build() as IDisposable;

Configuration

No response

Other information

No response

Author:	MaceWindu
Assignees:	-
Labels:	untriaged, area-Extensions-FileSystem
Milestone:	-

[ghost]

Tagging subscribers to this area: @dotnet/area-extensions-configuration
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

When application creates many short-living configuration roots, which use files it results in memory leaks around FileSystemWatcher class (in our case we setup test environment for each test and it leads to memory/performance issues as we have around 100k tests).

I've checked code and see that while ConfigurationRoot.Dispose disposes IConfigurationProvider instances, FileConfigurationProvider.Dispose disposes only _changeTokenRegistration and file (folder actually) watch infrastructure in FileConfigurationSource is never disposed.

Reproduction Steps

internal class Program
	{
		static void Main()
		{
			const int iterations = int.MaxValue;

			for (var i = 0; i < iterations; i++)
			{
				Test();
			}
		}

		static void Test()
		{
			var config = new ConfigurationBuilder().AddXmlFile("settings.xml", false, true).Build();

			(config as IDisposable)?.Dispose();
		}
	}

Expected behavior

No memory leaks

Actual behavior

Memory leaks

We need to support two runtimes currently, so results are for .NET7 and NET48

.NET 7 runtime after ~78k iterations

where byte[] instances are

In NETFX 4.8 situation is even worse (expected, as it doesn't have all improvements to file watcher related code)

Regression?

Nope

Known Workarounds

passing external PhysicalFileProvider instance and dispose it explicitly fixes leak completely:

using var fileProvider = new PhysicalFileProvider(AppContext.BaseDirectory);
using var config = new ConfigurationBuilder().AddXmlFile(fileProvider, "settings.xml", false, true).Build() as IDisposable;

Configuration

No response

Other information

No response

Author:	MaceWindu
Assignees:	-
Labels:	untriaged, area-Extensions-Configuration
Milestone:	-

[adamsitnik]

Hi @MaceWindu

Thank you for a bug report with repro case! I was able to repro the bug and send a fix: #86455

I've also created a proposal to help the users avoid getting into the leak: #86456

[adamsitnik]

I am reopening the issue (I am also going to unlock the conversation) because my fix introduced a bug and I need to revert it.