System.Text.Json using interpolated string with JsonSerializable.TypeInfoPropertyName fails with ArgumentException

[JakeYallop]

Description

The TypeInfoPropertyName property on the JsonSerializableAttribute is used to provide a unique name for a serializable class in case of naming conflicts.

Using an interpolated string (prefixed with $, now possible due to constant interpolated strings) for this property causes the generator to fail ungracefully with an ArgumentException.

I discovered this issue as I wanted to use nameof and then add a suffix to resolve a naming conflict.

Reproduction Steps

public class MyClass {}

[JsonSerializable(typeof(MyClass), TypeInfoPropertyName = $"{nameof(MyClass)}SomeUniqueSuffix")]
public partial class Context : JsonSerializerContext { }

The following variants also do not function as expected:

public class MyClass {}

//generates a type info property called "nameof"
[JsonSerializable(typeof(MyClass), TypeInfoPropertyName = nameof(MyClass) + "SomeUniqueSuffix")] 

//generates a type info property called "A"
[JsonSerializable(typeof(MyClass), TypeInfoPropertyName = "A" + "Suffix")]

public partial class Context : JsonSerializerContext { }

Expected behavior

Generator correctly parses the interpolated string, or fails gracefully with a diagnostic.

Actual behavior

warning CS8785: Generator 'JsonSourceGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'The hintName 'Context.$".g.cs' contains an invalid character '$' at position 8.

Regression?

No

Known Workarounds

Ensure a single string is used as the property value.

Configuration

.NET Version: 6.0
System.Text.Json version: 7.0.0-preview.4.22229.4

Other information

No response

[ghost]

Tagging subscribers to this area: @dotnet/area-system-text-json, @gregsdennis
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Issue Details

---

Description

The TypeInfoPropertyName property on the JsonSerializableAttribute is used to provide a unique name for a serializable class in case of naming conflicts.

Using an interpolated string (prefixed with $, now possible due to constant interpolated strings) for this property causes the generator to fail ungracefully with an ArgumentException.

I discovered this issue as I wanted to use nameof and then add a suffix to resolve a naming conflict.

Reproduction Steps

public class MyClass {}

[JsonSerializable(typeof(MyClass), TypeInfoPropertyName = $"{nameof(MyClass)}SomeUniqueSuffix")]
public partial class Context : JsonSerializerContext { }

The following variants also do not function as expected:

public class MyClass {}

//generates a type info property called "nameof"
[JsonSerializable(typeof(MyClass), TypeInfoPropertyName = nameof(MyClass) + "SomeUniqueSuffix")] 

//generates a type info property called "A"
[JsonSerializable(typeof(MyClass), TypeInfoPropertyName = "A" + "Suffix")]

public partial class Context : JsonSerializerContext { }

Expected behavior

Generator correctly parses the interpolated string, or fails gracefully with a diagnostic.

Actual behavior

warning CS8785: Generator 'JsonSourceGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'The hintName 'Context.$".g.cs' contains an invalid character '$' at position 8.

Regression?

No

Known Workarounds

Ensure a single string is used as the property value.

Configuration

.NET Version: 6.0
System.Text.Json version: 7.0.0-preview.4.22229.4

Other information

No response

Author:	JakeYallop
Assignees:	-
Labels:	area-System.Text.Json, untriaged
Milestone:	-

[layomia]

FYI @maryamariyan @joperezr for other source generators.

[joperezr]

cc: @stephentoub as well. I don't think this particular problem affects the Regex source generator since we have a static file name for the generated source produced by the generator, but it would be good to add tests for interpolation and concatenation on patterns in the attribute to make sure we handle that correctly. Same goes for the analyzer that I'm working for, making sure we handle concatenation correctly.

[JakeYallop]

A slight variation on the issue above - what would we expect the following to generate (this would probably be similar for the Regex generator, if we had the expression stored in a const field, and then used within the attribute?

public class Test {}
public static class Constants
{
    public const string TypeInfoName = "MyCustomName";
};

[JsonSerializable(typeof(Test), TypeInfoPropertyName = $"{Constants.TypeInfoName}" )]
public partial class Context : JsonSerializerContext { }