NRE in ConfigurationBinder.BindInstance

[RussKie]

Description

This looks like a regression which happened between 8.0.0-rc.2.23431.9 (3c48925) and 8.0.0-rc.2.23466.4 (287c10d).

Updating the 1P internal codebase to the latest .NET Extensions, several tests failed with the following stack trace:

at Microsoft.Extensions.Configuration.ConfigurationBinder.BindInstance(Type type, BindingPoint bindingPoint, IConfiguration config, BinderOptions options, Boolean isParentCollection)
at Microsoft.Extensions.Configuration.ConfigurationBinder.BindProperty(PropertyInfo property, Object instance, IConfiguration config, BinderOptions options)
at Microsoft.Extensions.Configuration.ConfigurationBinder.BindProperties(Object instance, IConfiguration configuration, BinderOptions options)
at Microsoft.Extensions.Configuration.ConfigurationBinder.BindInstance(Type type, BindingPoint bindingPoint, IConfiguration config, BinderOptions options, Boolean isParentCollection)
at Microsoft.Extensions.Configuration.ConfigurationBinder.Bind(IConfiguration configuration, Object instance, Action`1 configureOptions)
at Microsoft.Extensions.Options.NamedConfigureFromConfigurationOptions`1.<>c__DisplayClass1_0.<.ctor>b__0(TOptions options)
at Microsoft.Extensions.Options.ConfigureNamedOptions`1.Configure(String name, TOptions options)
at Microsoft.Extensions.Options.OptionsFactory`1.Create(String name)
at Microsoft.Extensions.Options.UnnamedOptionsManager`1.get_Value()

Reproduction Steps

I'm not familiar with this area of the runtime, nor I'm sufficiently familiar with the 1P codebase I'm updating to craft a standalone repro, so we may need to debug it interactively since this is an internal codebase.

Expected behavior

No NRE, everything continues work as before :)

Actual behavior

Tests fail

Regression?

Yes

Known Workarounds

No response

Configuration

No response

Other information

/cc: @geeknoid @joperezr

Tagging subscribers to this area: @dotnet/area-extensions-configuration
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Issue Details

---

Description

This looks like a regression which happened between 8.0.0-rc.2.23431.9 (3c48925) and 8.0.0-rc.2.23466.4 (287c10d).

Updating the 1P internal codebase to the latest .NET Extensions, several tests failed with the following stack trace:

at Microsoft.Extensions.Configuration.ConfigurationBinder.BindInstance(Type type, BindingPoint bindingPoint, IConfiguration config, BinderOptions options, Boolean isParentCollection)
at Microsoft.Extensions.Configuration.ConfigurationBinder.BindProperty(PropertyInfo property, Object instance, IConfiguration config, BinderOptions options)
at Microsoft.Extensions.Configuration.ConfigurationBinder.BindProperties(Object instance, IConfiguration configuration, BinderOptions options)
at Microsoft.Extensions.Configuration.ConfigurationBinder.BindInstance(Type type, BindingPoint bindingPoint, IConfiguration config, BinderOptions options, Boolean isParentCollection)
at Microsoft.Extensions.Configuration.ConfigurationBinder.Bind(IConfiguration configuration, Object instance, Action`1 configureOptions)
at Microsoft.Extensions.Options.NamedConfigureFromConfigurationOptions`1.<>c__DisplayClass1_0.<.ctor>b__0(TOptions options)
at Microsoft.Extensions.Options.ConfigureNamedOptions`1.Configure(String name, TOptions options)
at Microsoft.Extensions.Options.OptionsFactory`1.Create(String name)
at Microsoft.Extensions.Options.UnnamedOptionsManager`1.get_Value()

Reproduction Steps

I'm not familiar with this area of the runtime, nor I'm sufficiently familiar with the 1P codebase I'm updating to craft a standalone repro, so we may need to debug it interactively since this is an internal codebase.

Expected behavior

No NRE, everything continues work as before :)

Actual behavior

Tests fail

Regression?

Yes

Known Workarounds

No response

Configuration

No response

Other information

/cc: @geeknoid @joperezr

Author:	RussKie
Assignees:	-
Labels:	area-Extensions-Configuration
Milestone:	-

[tarekgh]

@RussKie if you can get us a standalone repro will be helpful to act on this issue.

Side question, do you know if the configuration binder source generator is enabled in your case?

[tarekgh]

@layomia FYI. no need to act on it till we gather more information. Thanks!

[ericstj]

I see the error that @RussKie provided points to https://domoreexp.visualstudio.com/R9/_git/3a5add3e-806c-495f-968c-4a688096398e?path=/test/Service/Middleware.UnexpectedRouteReporting.Tests/UnexpectedRouteExtensionsTest.cs&version=GBgeeknoid/net8&_a=contents

I was able to pull out the repro to a standalone app using their packages and I confirm the repro. I'll try to reduce it to not use their packages and share it.

[ericstj]

Here's the null ref: 35f043f#diff-2e6f75e1d4f577e1c8c1b6a32d158ce7812a38ad8fcd3b4d762157b92c03e890L308-R315

Will see if I can propose a fix and add a test. I'll work with @krwq if I can't get this done by end of PDT day.

[ericstj]

Yeah, this is due to Mock.GetSection returning null rather than a section without a value. We'll always return a value:

runtime/src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationRoot.cs

Lines 77 to 78 in 5883b72

	public IConfigurationSection GetSection(string key)
	=> new ConfigurationSection(this, key);

We should fix this and add a test case that uses Moq in a similar manner.

[ericstj]

Here's the isolated repro:
extNullRef.zip