EFCore_AsyncLocal_TestApp

Getting Started:

1. Clone the repository to your local workspace.
2. Open the TestApp.csproj file Visual Studio. This will load the entire project.
3. Add the details of your Postgres server here.
4. Build the project.
5. Start Debugging (F5) the project in VS.

Reproducing the issue:

What I've tried to demonstrate in this TestApp is that using multiple DbCommandInterceptor instances in the EFCore pipeline to intercept db requests causes AsyncLocal to lose context.

Using a single DbCommandInterceptor:

1. Comment out this line which adds CustomInterceptor_2 to DatabaseContext.
2. Build and start debugging the application.
3. Go to http://localhost:64116/user in your browser.
4. In your Visual Studio, the Debug logs in Output window, you should see the following statements:

Inside ReaderExecutingAsync of CustomInterceptor_1
Setting AsyncLocal value as 'Value_1'
Inside ReaderExecutedAsync of CustomInterceptor_1
Getting AsyncLocalContext Value: 'Value_1'

You can see that AsyncLocal preserves the value across ReaderExecutingAsync and ReaderExecutedAsync methods of CustomInterceptor_1

Using two DbCommandInterceptor:

1. Uncomment this line to add CustomInterceptor_2 to the db request pipeline.
2. Build and start debugging the application.
3. Go to http://localhost:64116/user in your browser.
4. In your Visual Studio, the Debug logs in Output window, you should see the following statements:

Inside ReaderExecutingAsync of CustomInterceptor_1
Setting AsyncLocal value as 'Value_1'
Inside ReaderExecutingAsync of CustomInterceptor_2
Inside ReaderExecutedAsync of CustomInterceptor_1
Getting AsyncLocalContext Value: ''
Inside ReaderExecutedAsync of CustomInterceptor_2

Note the statement "Getting AsyncLocalContext Value" has received null from AsyncLocal but Value_1 was set in the ReaderExecutingAsync of CustomInterceptor_1. This means that somehow using multiple instances of DbCommandInterceptor in the EFCore call chain causes inconsistency in the AsyncLocal.