Transient disposable ManualHealthCheck<> against dependency injection guideline

[KalleOlaviNiemitalo]

General IDisposable guidelines include:

• Don't register IDisposable instances with a transient lifetime. Use the factory pattern instead.

Contrary to this guideline, the CommonHealthChecksExtensions.AddManualHealthCheckDependencies method registers ManualHealthCheck<> with a transient lifetime, and it implements IDisposable. Its instances can therefore accumulate in the DI container if resolved from the root scope.

extensions/src/Libraries/Microsoft.Extensions.Diagnostics.HealthChecks.Common/CommonHealthChecksExtensions.Manual.cs

Lines 55 to 59 in b31f7e9

	private static IHealthChecksBuilder AddManualHealthCheckDependencies(this IHealthChecksBuilder builder)
	=> builder.Services
	.AddSingleton<ManualHealthCheckTracker>()
	.AddTransient(typeof(IManualHealthCheck<>), typeof(ManualHealthCheck<>))
	.AddHealthChecks();

extensions/src/Libraries/Microsoft.Extensions.Diagnostics.HealthChecks.Common/ManualHealthCheck.cs

Line 9 in b31f7e9

internal sealed class ManualHealthCheck<T> : IManualHealthCheck<T>

extensions/src/Libraries/Microsoft.Extensions.Diagnostics.HealthChecks.Common/IManualHealthCheck.cs

Line 23 in b31f7e9

public interface IManualHealthCheck<T> : IManualHealthCheck

extensions/src/Libraries/Microsoft.Extensions.Diagnostics.HealthChecks.Common/IManualHealthCheck.cs

Line 11 in b31f7e9

public interface IManualHealthCheck : IDisposable