Configuration Binding source generator throws InvalidOperationException at runtime for type with custom [TypeConverter] use within a dictionary

[martincostello]

Description

If the configuration binding source generator is used with a type that uses a custom [TypeConverter] to parse the type from a string, the generated code will throw an InvalidOperationException at runtime because properties are not present in the configuration that map to the object's properties when the value is a value in a dictionary.

For example, if this type is used for this configuration object in conjunction with a JSON configuration such as:

{
  "Site": {
    "Keyed": {
      "Somewhere": "0,0"
    }
  }
}

The same issue does not seem to occur if the object is not within a dictionary. I have not tested the behavior when the object is a member of an array.

Reproduction Steps

1. Clone martincostello/config-binding-source-generator-typeconverter-repro
2. Run dotnet run --project .\Repro\

Expected behavior

The configuration binding source generator produces code that is able to use the type converter to produce an instance of the given type from the string Value property of the IConfiguration passed to the generated method.

Actual behavior

An InvalidOperationException is thrown the first time the application attempts to retrieve the bound configuration object.

Unhandled exception. System.InvalidOperationException: Cannot create instance of type 'Repro.Geolocation' because parameter 'latitude' has no matching config. Each parameter in the constructor that does not have a default value must have a corresponding config entry.
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.InitializeGeolocation(IConfiguration configuration, BinderOptions binderOptions) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 174
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.BindCore(IConfiguration configuration, IDictionary`2& instance, Boolean defaultValueIfNotFound, BinderOptions binderOptions) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 134
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.BindCore(IConfiguration configuration, SiteOptions& instance, Boolean defaultValueIfNotFound, BinderOptions binderOptions) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 160
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.BindCoreMain(IConfiguration configuration, Object instance, Type type, Action`1 configureOptions) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 83
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.<>c__DisplayClass1_0`1.<Configure>b__0(TOptions instance) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 58
   at Microsoft.Extensions.Options.OptionsFactory`1.Create(String name)
   at Microsoft.Extensions.Options.UnnamedOptionsManager`1.get_Value()
   at Program.<Main>$(String[] args) in .\config-binding-source-generator-typeconverter-repro\Repro\Program.cs:line 11

Regression?

Unknown compared to the previews and rc.1 - I had the configuration binding source generator disabled before RC2 due to #90851, #90987 and #91258 that prevented my code from running this far.

Known Workarounds

Disable the configuration binding source generator or refactor code to not use a custom [TypeConverter].

Configuration

.NET SDK 8.0.100-rc.2.23502.2

Other information

No response

[ghost]

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

---

Description

If the configuration binding source generator is used with a type that uses a custom [TypeConverter] to parse the type from a string, the generated code will throw an InvalidOperationException at runtime because properties are not present in the configuration that map to the object's properties when the value is a value in a dictionary.

For example, if this type is used for this configuration object in conjunction with a JSON configuration such as:

{
  "Site": {
    "Keyed": {
      "Somewhere": "0,0"
    }
  }
}

The same issue does not seem to occur if the object is not within a dictionary. I have not tested the behavior when the object is a member of an array.

Reproduction Steps

1. Clone martincostello/config-binding-source-generator-typeconverter-repro
2. Run dotnet run --project .\Repro\

Expected behavior

The configuration binding source generator produces code that is able to use the type converter to produce an instance of the given type from the string Value property of the IConfiguration passed to the generated method.

Actual behavior

An InvalidOperationException is thrown the first time the application attempts to retrieve the bound configuration object.

Unhandled exception. System.InvalidOperationException: Cannot create instance of type 'Repro.Geolocation' because parameter 'latitude' has no matching config. Each parameter in the constructor that does not have a default value must have a corresponding config entry.
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.InitializeGeolocation(IConfiguration configuration, BinderOptions binderOptions) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 174
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.BindCore(IConfiguration configuration, IDictionary`2& instance, Boolean defaultValueIfNotFound, BinderOptions binderOptions) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 134
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.BindCore(IConfiguration configuration, SiteOptions& instance, Boolean defaultValueIfNotFound, BinderOptions binderOptions) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 160
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.BindCoreMain(IConfiguration configuration, Object instance, Type type, Action`1 configureOptions) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 83
   at Microsoft.Extensions.Configuration.Binder.SourceGeneration.<BindingExtensions_g>FC276FD7C89D1ED0B2B3E96BAC8F157FABB86A642EAABC54639B357A857C01D08__BindingExtensions.<>c__DisplayClass1_0`1.<Configure>b__0(TOptions instance) in .\config-binding-source-generator-typeconverter-repro\Repro\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs:line 58
   at Microsoft.Extensions.Options.OptionsFactory`1.Create(String name)
   at Microsoft.Extensions.Options.UnnamedOptionsManager`1.get_Value()
   at Program.<Main>$(String[] args) in .\config-binding-source-generator-typeconverter-repro\Repro\Program.cs:line 11

Regression?

Unknown compared to the previews and rc.1 - I had the configuration binding source generator disabled before RC2 due to #90851, #90987 and #91258 that prevented my code from running this far.

Known Workarounds

Disable the configuration binding source generator or refactor code to not use a custom [TypeConverter].

Configuration

.NET SDK 8.0.100-rc.2.23502.2

Other information

No response

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

[ericstj]

This was intentionally out of scope for v1 of the configuration source generator. Please see #83599 for the way we're thinking about handling this as well as suggested workarounds.

[martincostello]

Fair enough - I did think it weird though that it doesn't work in a dictionary, but it seemed to work outside of one.

However, I just tweaked my code a bit and had another look and in the case of it not being in a dictionary, it instead just silently doesn't bind anything at all and you get left with the default value, rather than an exception being thrown.

Repro/appsettings.json

-    "Keyed": {
-      "Somewhere": "0,0"
-    }
+    "Single": "1,2"

Repro/Program.cs

- _ = app.Services.GetRequiredService<IOptions<SiteOptions>>().Value;
+ var opts = app.Services.GetRequiredService<IOptions<SiteOptions>>().Value;
+ Console.WriteLine(opts.Single);

Output:

0,0