Skip to content

Fix JSON schema nullability for readonly properties #132271

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Youssef1313 wants to merge 4 commits into
base: main
Choose a base branch
from
+41 −1
Open

Fix JSON schema nullability for readonly properties #132271

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
97def59
Fix JSON schema nullability for readonly properties
Youssef1313 Aug 13, 2026
cb77d27
Update JsonSchemaExporterTests.cs
Youssef1313 Aug 13, 2026
cb11f0e
Make internal
Youssef1313 Aug 13, 2026
a636462
Update JsonSchemaExporterTests.cs
Youssef1313 Aug 14, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 2 additions & 1 deletion src/libraries/System.Text.Json/src/System/Text/Json/Schema/JsonSchemaExporter.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -447,7 +447,8 @@ bool IsNullableSchema(JsonSchemaExporterOptions options)

if (propertyInfo is not null)
{
return propertyInfo.IsGetNullable || propertyInfo.IsSetNullable;
return (propertyInfo.Get is not null && propertyInfo.IsGetNullable) ||

@Youssef1313 Youssef1313 Aug 14, 2026

Copy link
Copy Markdown
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@eiriktsarpalis I'm thinking more. Is this whole idea even correct? A property isn't necessarily writeable only via a setter. It could be writeable via a constructor.

public class C
{
    public C(string? s) => S = s ?? string.Empty;

    // get-only property. Non-nullable.
    // But a null is okay to get deserialized.
    // It's not produced by serialization, though.
    public string S { get; }
}

(propertyInfo.Set is not null && propertyInfo.IsSetNullable);
Comment thread
Youssef1313 marked this conversation as resolved.
}

if (typeInfo.IsNullable)
Expand Down
39 changes: 39 additions & 0 deletions src/libraries/System.Text.Json/tests/Common/JsonSchemaExporterTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,30 @@ public void TreatNullObliviousAsNonNullable_True_MarksReferenceTypesAsNonNullabl
Assert.Equal(expectedType, (string)schema["type"]!);
}

[Fact]
public void GetOnlyProperties_DoNotUseSetterNullabilityInSchema()
{
JsonNode schema = Serializer.DefaultOptions.GetJsonSchemaAsNode(typeof(PocoWithGetOnlyProperties));
const string ExpectedJsonSchema = """
{
"type": ["object", "null"],
"properties": {
"Values": {
"type": "array",
"items": { "type": ["string", "null"] }
},
"SingleValueGetOnly": { "type": "string" },
"NullableGetOnly": { "type": ["string", "null"] },
"SingleValueGetSet": { "type": "string" },
"NonNullableReadonlyField": { "type": "string" },
"NullableReadonlyField": { "type": ["string", "null"] }
}
}
""";

AssertValidJsonSchema(typeof(PocoWithGetOnlyProperties), ExpectedJsonSchema, schema);
}

[Theory]
[InlineData(typeof(Type))]
[InlineData(typeof(MethodInfo))]
Expand Down Expand Up @@ -262,6 +286,21 @@ public void LegacySchemaExporter_CanAccessReflectedMembers()

record PocoWithProperty(int Value);

sealed class PocoWithGetOnlyProperties
{
public IEnumerable<string> Values => [];
public string SingleValueGetOnly { get; } = "value";
public string? NullableGetOnly { get; }
public string SingleValueGetSet { get; set; } = "value";
[JsonInclude]
public readonly string NonNullableReadonlyField = "value";

#pragma warning disable CS0649 // field never assigned to
[JsonInclude]
public readonly string? NullableReadonlyField;
#pragma warning restore CS0649
}

[JsonSerializable(typeof(PocoWithProperty))]
partial class PocoWithPropertyContext : JsonSerializerContext;

Expand Down
Loading