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Map [MinLength]/[MaxLength] on dictionary properties to minProperties / maxProperties #3922

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Merged
martincostello merged 8 commits into from
Jun 16, 2026
Merged

Map [MinLength]/[MaxLength] on dictionary properties to minProperties / maxProperties #3922

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8b67fbf
Map [MinLength]/[MaxLength]/[Length] on dictionary schemas to minProp…
KitKeen Apr 24, 2026
e8951b0
Extend #3915 test coverage
KitKeen Apr 24, 2026
1af7979
Address review feedback for #3922
KitKeen Apr 25, 2026
d7dd288
Rename DictionaryWithLength fixture property to DictionaryWithLengthA…
KitKeen Apr 25, 2026
8e5c670
Rename dictionary fixture properties to not imply attribute presence
KitKeen Apr 25, 2026
743061c
Replace manual JSON assertion with Verify snapshot test for bounded d…
KitKeen May 3, 2026
2d8e31e
Add bounded-dictionary Verify snapshots for net8.0 and net9.0
KitKeen May 20, 2026
54c1cee
Use short type name in snapshot filenames to fit Windows MAX_PATH
KitKeen May 26, 2026
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13 changes: 13 additions & 0 deletions src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/OpenApiSchemaExtensions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -185,6 +185,10 @@ private static void ApplyMinLengthAttribute(OpenApiSchema schema, MinLengthAttri
{
schema.MinItems = minLengthAttribute.Length;
}
else if (schema.Type is { } objectType && objectType.HasFlag(JsonSchemaTypes.Object))
{
schema.MinProperties = minLengthAttribute.Length;
}
else
{
schema.MinLength = minLengthAttribute.Length;
Expand All @@ -209,6 +213,10 @@ private static void ApplyMaxLengthAttribute(OpenApiSchema schema, MaxLengthAttri
{
schema.MaxItems = maxLengthAttribute.Length;
}
else if (schema.Type is { } objectType && objectType.HasFlag(JsonSchemaTypes.Object))
{
schema.MaxProperties = maxLengthAttribute.Length;
}
else
{
schema.MaxLength = maxLengthAttribute.Length;
Expand All @@ -234,6 +242,11 @@ private static void ApplyLengthAttribute(OpenApiSchema schema, LengthAttribute l
schema.MinItems = lengthAttribute.MinimumLength;
schema.MaxItems = lengthAttribute.MaximumLength;
}
else if (schema.Type is { } objectType && objectType.HasFlag(JsonSchemaTypes.Object))
{
schema.MinProperties = lengthAttribute.MinimumLength;
schema.MaxProperties = lengthAttribute.MaximumLength;
}
else
{
schema.MinLength = lengthAttribute.MinimumLength;
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6 changes: 6 additions & 0 deletions .../Swashbuckle.AspNetCore.Newtonsoft.Test/SchemaGenerator/NewtonsoftSchemaGeneratorTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -373,10 +373,16 @@ public void GenerateSchema_SetsValidationProperties_IfComplexTypeHasValidationAt
Assert.Equal(3, schema.Properties["StringWithMinMaxLength"].MaxLength);
Assert.Equal(1, schema.Properties["ArrayWithMinMaxLength"].MinItems);
Assert.Equal(3, schema.Properties["ArrayWithMinMaxLength"].MaxItems);
Assert.Equal(1, schema.Properties["DictionaryWithMinMaxLength"].MinProperties);
Assert.Equal(3, schema.Properties["DictionaryWithMinMaxLength"].MaxProperties);
Assert.Null(schema.Properties["DictionaryWithMinMaxLength"].MinLength);
Assert.Null(schema.Properties["DictionaryWithMinMaxLength"].MaxLength);
Assert.Equal(1, schema.Properties["StringWithLength"].MinLength);
Assert.Equal(3, schema.Properties["StringWithLength"].MaxLength);
Assert.Equal(1, schema.Properties["ArrayWithLength"].MinItems);
Assert.Equal(3, schema.Properties["ArrayWithLength"].MaxItems);
Assert.Equal(1, schema.Properties["DictionaryWithLength"].MinProperties);
Assert.Equal(3, schema.Properties["DictionaryWithLength"].MaxProperties);
Assert.NotNull(schema.Properties["IntWithExclusiveRange"].ExclusiveMinimum);
Assert.NotNull(schema.Properties["IntWithExclusiveRange"].ExclusiveMaximum);
Assert.Equal("byte", schema.Properties["StringWithBase64"].Format);
Expand Down
6 changes: 6 additions & 0 deletions ...shbuckle.AspNetCore.SwaggerGen.Test/SchemaGenerator/JsonSerializerSchemaGeneratorTests.cs
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Expand Up @@ -373,10 +373,16 @@ public void GenerateSchema_SetsValidationProperties_IfComplexTypeHasValidationAt
Assert.Equal(3, schema.Properties["StringWithMinMaxLength"].MaxLength);
Assert.Equal(1, schema.Properties["ArrayWithMinMaxLength"].MinItems);
Assert.Equal(3, schema.Properties["ArrayWithMinMaxLength"].MaxItems);
Assert.Equal(1, schema.Properties["DictionaryWithMinMaxLength"].MinProperties);
Assert.Equal(3, schema.Properties["DictionaryWithMinMaxLength"].MaxProperties);
Assert.Null(schema.Properties["DictionaryWithMinMaxLength"].MinLength);
Assert.Null(schema.Properties["DictionaryWithMinMaxLength"].MaxLength);
Assert.Equal(1, schema.Properties["StringWithLength"].MinLength);
Assert.Equal(3, schema.Properties["StringWithLength"].MaxLength);
Assert.Equal(1, schema.Properties["ArrayWithLength"].MinItems);
Assert.Equal(3, schema.Properties["ArrayWithLength"].MaxItems);
Assert.Equal(1, schema.Properties["DictionaryWithLength"].MinProperties);
Assert.Equal(3, schema.Properties["DictionaryWithLength"].MaxProperties);
Assert.NotNull(schema.Properties["IntWithExclusiveRange"].ExclusiveMinimum);
Assert.NotNull(schema.Properties["IntWithExclusiveRange"].ExclusiveMaximum);
Assert.Equal("byte", schema.Properties["StringWithBase64"].Format);
Expand Down
186 changes: 185 additions & 1 deletion test/Swashbuckle.AspNetCore.SwaggerGen.Test/SwaggerGenerator/OpenApiSchemaExtensionsTests.cs
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@@ -1,4 +1,5 @@
using System.ComponentModel.DataAnnotations;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Globalization;
using Microsoft.OpenApi;

Expand Down Expand Up @@ -149,6 +150,189 @@ public static void ApplyValidationAttributes_Handles_DataTypeAttribute_CustomDat
Assert.Equal(customDataType, schema.Format);
}

[Fact]
public static void ApplyValidationAttributes_MinLength_On_Dictionary_Maps_To_MinProperties()
{
// Arrange — dictionary schema is represented as an Object with AdditionalProperties
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var schema = new OpenApiSchema
{
Type = JsonSchemaType.Object,
AdditionalPropertiesAllowed = true,
AdditionalProperties = new OpenApiSchema { Type = JsonSchemaType.String },
};

// Act
schema.ApplyValidationAttributes([new MinLengthAttribute(1)]);

// Assert
Assert.Equal(1, schema.MinProperties);
Assert.Null(schema.MinLength);
Assert.Null(schema.MinItems);
}

[Fact]
public static void ApplyValidationAttributes_MaxLength_On_Dictionary_Maps_To_MaxProperties()
{
// Arrange
var schema = new OpenApiSchema
{
Type = JsonSchemaType.Object,
AdditionalPropertiesAllowed = true,
AdditionalProperties = new OpenApiSchema { Type = JsonSchemaType.String },
};

// Act
schema.ApplyValidationAttributes([new MaxLengthAttribute(10)]);

// Assert
Assert.Equal(10, schema.MaxProperties);
Assert.Null(schema.MaxLength);
Assert.Null(schema.MaxItems);
}

[Fact]
public static void ApplyValidationAttributes_Length_On_Dictionary_Maps_To_Min_And_MaxProperties()
{
// Arrange
var schema = new OpenApiSchema
{
Type = JsonSchemaType.Object,
AdditionalPropertiesAllowed = true,
AdditionalProperties = new OpenApiSchema { Type = JsonSchemaType.String },
};

// Act
schema.ApplyValidationAttributes([new LengthAttribute(2, 5)]);

// Assert
Assert.Equal(2, schema.MinProperties);
Assert.Equal(5, schema.MaxProperties);
Assert.Null(schema.MinLength);
Assert.Null(schema.MaxLength);
Assert.Null(schema.MinItems);
Assert.Null(schema.MaxItems);
}

[Fact]
public static void ApplyValidationAttributes_MinLength_On_String_Still_Maps_To_MinLength()
{
// Arrange — regression guard for the existing string path
var schema = new OpenApiSchema { Type = JsonSchemaType.String };

// Act
schema.ApplyValidationAttributes([new MinLengthAttribute(3)]);

// Assert
Assert.Equal(3, schema.MinLength);
Assert.Null(schema.MinProperties);
Assert.Null(schema.MinItems);
}

[Fact]
public static void ApplyValidationAttributes_MinLength_On_Array_Still_Maps_To_MinItems()
{
// Arrange — regression guard for the existing array path
var schema = new OpenApiSchema { Type = JsonSchemaType.Array };

// Act
schema.ApplyValidationAttributes([new MinLengthAttribute(3)]);

// Assert
Assert.Equal(3, schema.MinItems);
Assert.Null(schema.MinProperties);
Assert.Null(schema.MinLength);
}

[Fact]
public static void ApplyValidationAttributes_MaxLength_On_String_Still_Maps_To_MaxLength()
{
var schema = new OpenApiSchema { Type = JsonSchemaType.String };

schema.ApplyValidationAttributes([new MaxLengthAttribute(5)]);

Assert.Equal(5, schema.MaxLength);
Assert.Null(schema.MaxProperties);
Assert.Null(schema.MaxItems);
}

[Fact]
public static void ApplyValidationAttributes_MaxLength_On_Array_Still_Maps_To_MaxItems()
{
var schema = new OpenApiSchema { Type = JsonSchemaType.Array };

schema.ApplyValidationAttributes([new MaxLengthAttribute(5)]);

Assert.Equal(5, schema.MaxItems);
Assert.Null(schema.MaxProperties);
Assert.Null(schema.MaxLength);
}

[Fact]
public static void ApplyValidationAttributes_Length_On_String_Still_Maps_To_MinAndMaxLength()
{
var schema = new OpenApiSchema { Type = JsonSchemaType.String };

schema.ApplyValidationAttributes([new LengthAttribute(1, 5)]);

Assert.Equal(1, schema.MinLength);
Assert.Equal(5, schema.MaxLength);
Assert.Null(schema.MinProperties);
Assert.Null(schema.MaxProperties);
}

[Fact]
public static void ApplyValidationAttributes_Length_On_Array_Still_Maps_To_MinAndMaxItems()
{
var schema = new OpenApiSchema { Type = JsonSchemaType.Array };

schema.ApplyValidationAttributes([new LengthAttribute(1, 5)]);

Assert.Equal(1, schema.MinItems);
Assert.Equal(5, schema.MaxItems);
Assert.Null(schema.MinProperties);
Assert.Null(schema.MaxProperties);
}

[Fact]
public static void ApplyValidationAttributes_MinLength_On_EnumKeyedDictionarySchema_Maps_To_MinProperties()
{
// Enum-keyed dictionaries are emitted as Object with known Properties and
// AdditionalPropertiesAllowed = false (see SchemaGenerator.CreateDictionarySchema).
// The fix must still route MinLength to MinProperties in this shape.
var schema = new OpenApiSchema
{
Type = JsonSchemaType.Object,
Properties = new Dictionary<string, IOpenApiSchema>
{
["Foo"] = new OpenApiSchema { Type = JsonSchemaType.String },
["Bar"] = new OpenApiSchema { Type = JsonSchemaType.String },
},
AdditionalPropertiesAllowed = false,
};

schema.ApplyValidationAttributes([new MinLengthAttribute(1)]);

Assert.Equal(1, schema.MinProperties);
Assert.Null(schema.MinLength);
}

[Fact]
public static void ApplyValidationAttributes_MinLength_On_NullableObjectSchema_Maps_To_MinProperties()
{
// A nullable dictionary has Type = Object | Null. HasFlag(Object) must still route to MinProperties.
var schema = new OpenApiSchema
{
Type = JsonSchemaType.Object | JsonSchemaType.Null,
AdditionalPropertiesAllowed = true,
AdditionalProperties = new OpenApiSchema { Type = JsonSchemaType.String },
};

schema.ApplyValidationAttributes([new MinLengthAttribute(2)]);

Assert.Equal(2, schema.MinProperties);
Assert.Null(schema.MinLength);
}

private sealed class CultureSwitcher : IDisposable
{
private readonly CultureInfo _previous;
Expand Down
9 changes: 8 additions & 1 deletion test/Swashbuckle.AspNetCore.TestSupport/Fixtures/TypeWithValidationAttributes.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
using System.ComponentModel;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;

namespace Swashbuckle.AspNetCore.TestSupport;
Expand All @@ -14,12 +15,18 @@ public class TypeWithValidationAttributes
[MinLength(1), MaxLength(3)]
public string[] ArrayWithMinMaxLength { get; set; }

[MinLength(1), MaxLength(3)]
public IReadOnlyDictionary<string, string> DictionaryWithMinMaxLength { get; set; }

[Length(1, 3)]
public string StringWithLength { get; set; }

[Length(1, 3)]
public string[] ArrayWithLength { get; set; }

[Length(1, 3)]
public Dictionary<string, string> DictionaryWithLength { get; set; }

[Range(1, 10, MinimumIsExclusive = true, MaximumIsExclusive = true)]
public int IntWithExclusiveRange { get; set; }

Expand Down
13 changes: 12 additions & 1 deletion ...washbuckle.AspNetCore.TestSupport/Fixtures/TypeWithValidationAttributesViaMetadataType.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
using System.ComponentModel;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using Microsoft.AspNetCore.Mvc;

Expand All @@ -13,10 +14,14 @@ public class TypeWithValidationAttributesViaMetadataType

public string[] ArrayWithMinMaxLength { get; set; }

public IReadOnlyDictionary<string, string> DictionaryWithMinMaxLength { get; set; }
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public string StringWithLength { get; set; }

public string[] ArrayWithLength { get; set; }

public Dictionary<string, string> DictionaryWithLength { get; set; }
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public string StringWithBase64 { get; set; }

public double IntWithExclusiveRange { get; set; }
Expand Down Expand Up @@ -49,12 +54,18 @@ public class MetadataType
[MinLength(1), MaxLength(3)]
public string[] ArrayWithMinMaxLength { get; set; }

[MinLength(1), MaxLength(3)]
public IReadOnlyDictionary<string, string> DictionaryWithMinMaxLength { get; set; }

[Length(1, 3)]
public string StringWithLength { get; set; }

[Length(1, 3)]
public string[] ArrayWithLength { get; set; }

[Length(1, 3)]
public Dictionary<string, string> DictionaryWithLength { get; set; }

[Range(1, 10, MinimumIsExclusive = true, MaximumIsExclusive = true)]
public int IntWithExclusiveRange { get; set; }

Expand Down