chore: revert collections to use interface types

Author: MaggieKimani1

src/Microsoft.OpenApi.Hidi/Formatters/PowerShellFormatter.cs

@@ -77,7 +77,7 @@ public override void Visit(OpenApiOperation operation)
             // Order matters. Resolve operationId.
             operationId = RemoveHashSuffix(operationId);
             if (operationTypeExtension.IsEquals("action") || operationTypeExtension.IsEquals("function"))
-                operationId = RemoveKeyTypeSegment(operationId, operation.Parameters ?? []);
+                operationId = RemoveKeyTypeSegment(operationId, operation.Parameters ?? new List<IOpenApiParameter>());
             operationId = SingularizeAndDeduplicateOperationId(operationId.SplitByChar('.'));
             operationId = ResolveODataCastOperationId(operationId);
             operationId = ResolveByRefOperationId(operationId);
@@ -145,7 +145,7 @@ private static string RemoveHashSuffix(string operationId)
             return s_hashSuffixRegex.Match(operationId).Value;
         }
 
-        private static string RemoveKeyTypeSegment(string operationId, List<IOpenApiParameter> parameters)
+        private static string RemoveKeyTypeSegment(string operationId, IList<IOpenApiParameter> parameters)
         {
             var segments = operationId.SplitByChar('.');
             foreach (var parameter in parameters)
@@ -159,7 +159,7 @@ private static string RemoveKeyTypeSegment(string operationId, List<IOpenApiPara
             return string.Join('.', segments);
         }
 
-        private static void ResolveFunctionParameters(List<IOpenApiParameter> parameters)
+        private static void ResolveFunctionParameters(IList<IOpenApiParameter> parameters)
         {
             foreach (var parameter in parameters.OfType<OpenApiParameter>().Where(static p => p.Content?.Count > 0))
             {

src/Microsoft.OpenApi/Models/Interfaces/IOpenApiPathItem.cs

@@ -19,11 +19,11 @@ public interface IOpenApiPathItem : IOpenApiDescribedElement, IOpenApiSummarized
     /// <summary>
     /// An alternative server array to service all operations in this path.
     /// </summary>
-    public List<OpenApiServer>? Servers { get; }
+    public IList<OpenApiServer>? Servers { get; }
 
     /// <summary>
     /// A list of parameters that are applicable for all the operations described under this path.
     /// These parameters can be overridden at the operation level, but cannot be removed there.
     /// </summary>
-    public List<IOpenApiParameter>? Parameters { get; }
+    public IList<IOpenApiParameter>? Parameters { get; }
 }

src/Microsoft.OpenApi/Models/Interfaces/IOpenApiSchema.cs

@@ -145,19 +145,19 @@ public interface IOpenApiSchema : IOpenApiDescribedElement, IOpenApiReadOnlyExte
     /// Follow JSON Schema definition: https://json-schema.org/draft/2020-12/json-schema-validation
     /// Inline or referenced schema MUST be of a Schema Object and not a standard JSON Schema.
     /// </summary>
-    public List<IOpenApiSchema>? AllOf { get; }
+    public IList<IOpenApiSchema>? AllOf { get; }
 
     /// <summary>
     /// Follow JSON Schema definition: https://json-schema.org/draft/2020-12/json-schema-validation
     /// Inline or referenced schema MUST be of a Schema Object and not a standard JSON Schema.
     /// </summary>
-    public List<IOpenApiSchema>? OneOf { get; }
+    public IList<IOpenApiSchema>? OneOf { get; }
 
     /// <summary>
     /// Follow JSON Schema definition: https://json-schema.org/draft/2020-12/json-schema-validation
     /// Inline or referenced schema MUST be of a Schema Object and not a standard JSON Schema.
     /// </summary>
-    public List<IOpenApiSchema>? AnyOf { get; }
+    public IList<IOpenApiSchema>? AnyOf { get; }
 
     /// <summary>
     /// Follow JSON Schema definition: https://json-schema.org/draft/2020-12/json-schema-validation
@@ -168,7 +168,7 @@ public interface IOpenApiSchema : IOpenApiDescribedElement, IOpenApiReadOnlyExte
     /// <summary>
     /// Follow JSON Schema definition: https://json-schema.org/draft/2020-12/json-schema-validation
     /// </summary>
-    public HashSet<string>? Required { get; }
+    public ISet<string>? Required { get; }
 
     /// <summary>
     /// Follow JSON Schema definition: https://json-schema.org/draft/2020-12/json-schema-validation
@@ -247,12 +247,12 @@ public interface IOpenApiSchema : IOpenApiDescribedElement, IOpenApiReadOnlyExte
     /// To represent examples that cannot be naturally represented in JSON or YAML, 
     /// a list of values can be used to contain the examples with escaping where necessary.
     /// </summary>
-    public List<JsonNode>? Examples { get; }
+    public IList<JsonNode>? Examples { get; }
 
     /// <summary>
     /// Follow JSON Schema definition: https://json-schema.org/draft/2020-12/json-schema-validation
     /// </summary>
-    public List<JsonNode>? Enum { get; }
+    public IList<JsonNode>? Enum { get; }
 
     /// <summary>
     /// Follow JSON Schema definition: https://json-schema.org/draft/2020-12/json-schema-validation

src/Microsoft.OpenApi/Models/OpenApiDocument.cs

@@ -49,7 +49,7 @@ public void RegisterComponents()
         /// <summary>
         /// An array of Server Objects, which provide connectivity information to a target server.
         /// </summary>
-        public List<OpenApiServer>? Servers { get; set; } = [];
+        public IList<OpenApiServer>? Servers { get; set; } = [];
 
         /// <summary>
         /// REQUIRED. The available paths and operations for the API.
@@ -71,13 +71,13 @@ public void RegisterComponents()
         /// <summary>
         /// A declaration of which security mechanisms can be used across the API.
         /// </summary>
-        public List<OpenApiSecurityRequirement>? Security { get; set; }
+        public IList<OpenApiSecurityRequirement>? Security { get; set; }
 
-        private HashSet<OpenApiTag>? _tags;
+        private ISet<OpenApiTag>? _tags;
         /// <summary>
         /// A list of tags used by the specification with additional metadata.
         /// </summary>
-        public HashSet<OpenApiTag>? Tags 
+        public ISet<OpenApiTag>? Tags 
         { 
             get
             {
@@ -414,7 +414,7 @@ public void SerializeAsV2(IOpenApiWriter writer)
             return server.ReplaceServerUrlVariables([]);
         }
 
-        private static void WriteHostInfoV2(IOpenApiWriter writer, List<OpenApiServer>? servers)
+        private static void WriteHostInfoV2(IOpenApiWriter writer, IList<OpenApiServer>? servers)
         {
             if (servers == null || !servers.Any())
             {

src/Microsoft.OpenApi/Models/OpenApiOperation.cs

@@ -22,12 +22,12 @@ public class OpenApiOperation : IOpenApiSerializable, IOpenApiExtensible, IMetad
         /// </summary>
         public const bool DeprecatedDefault = false;
 
-        private HashSet<OpenApiTagReference>? _tags;
+        private ISet<OpenApiTagReference>? _tags;
         /// <summary>
         /// A list of tags for API documentation control.
         /// Tags can be used for logical grouping of operations by resources or any other qualifier.
         /// </summary>
-        public HashSet<OpenApiTagReference>? Tags 
+        public ISet<OpenApiTagReference>? Tags 
         { 
             get
             {
@@ -74,7 +74,7 @@ public HashSet<OpenApiTagReference>? Tags
         /// The list MUST NOT include duplicated parameters. A unique parameter is defined by a combination of a name and location.
         /// The list can use the Reference Object to link to parameters that are defined at the OpenAPI Object's components/parameters.
         /// </summary>
-        public List<IOpenApiParameter>? Parameters { get; set; }
+        public IList<IOpenApiParameter>? Parameters { get; set; }
 
         /// <summary>
         /// The request body applicable for this operation.
@@ -111,14 +111,14 @@ public HashSet<OpenApiTagReference>? Tags
         /// This definition overrides any declared top-level security.
         /// To remove a top-level security declaration, an empty array can be used.
         /// </summary>
-        public List<OpenApiSecurityRequirement>? Security { get; set; }
+        public IList<OpenApiSecurityRequirement>? Security { get; set; }
 
         /// <summary>
         /// An alternative server array to service this operation.
         /// If an alternative server object is specified at the Path Item Object or Root level,
         /// it will be overridden by this value.
         /// </summary>
-        public List<OpenApiServer>? Servers { get; set; }
+        public IList<OpenApiServer>? Servers { get; set; }
 
         /// <summary>
         /// This object MAY be extended with Specification Extensions.
@@ -139,7 +139,7 @@ public OpenApiOperation() { }
         public OpenApiOperation(OpenApiOperation operation)
         {
             Utils.CheckArgumentNull(operation);
-            Tags = operation.Tags != null ? [.. operation.Tags] : null;
+            Tags = operation.Tags != null ? new HashSet<OpenApiTagReference>(operation.Tags) : null;
             Summary = operation.Summary ?? Summary;
             Description = operation.Description ?? Description;
             ExternalDocs = operation.ExternalDocs != null ? new(operation.ExternalDocs) : null;
@@ -357,7 +357,7 @@ public virtual void SerializeAsV2(IOpenApiWriter writer)
             writer.WriteEndObject();
         }
 
-        private static HashSet<OpenApiTagReference>? VerifyTagReferences(HashSet<OpenApiTagReference>? tags)
+        private static ISet<OpenApiTagReference>? VerifyTagReferences(ISet<OpenApiTagReference>? tags)
         {
             if (tags?.Count > 0)
             {

src/Microsoft.OpenApi/Models/OpenApiPathItem.cs

@@ -25,10 +25,10 @@ public class OpenApiPathItem : IOpenApiExtensible, IOpenApiPathItem
         public Dictionary<HttpMethod, OpenApiOperation>? Operations { get; set; }
 
         /// <inheritdoc/>
-        public List<OpenApiServer>? Servers { get; set; }
+        public IList<OpenApiServer>? Servers { get; set; }
 
         /// <inheritdoc/>
-        public List<IOpenApiParameter>? Parameters { get; set; }
+        public IList<IOpenApiParameter>? Parameters { get; set; }
 
         /// <inheritdoc/>
         public IDictionary<string, IOpenApiExtension>? Extensions { get; set; }

src/Microsoft.OpenApi/Models/OpenApiSchema.cs

@@ -180,19 +180,19 @@ public string? Minimum
         public bool WriteOnly { get; set; }
 
         /// <inheritdoc />
-        public List<IOpenApiSchema>? AllOf { get; set; }
+        public IList<IOpenApiSchema>? AllOf { get; set; }
 
         /// <inheritdoc />
-        public List<IOpenApiSchema>? OneOf { get; set; }
+        public IList<IOpenApiSchema>? OneOf { get; set; }
 
         /// <inheritdoc />
-        public List<IOpenApiSchema>? AnyOf { get; set; }
+        public IList<IOpenApiSchema>? AnyOf { get; set; }
 
         /// <inheritdoc />
         public IOpenApiSchema? Not { get; set; }
 
         /// <inheritdoc />
-        public HashSet<string>? Required { get; set; }
+        public ISet<string>? Required { get; set; }
 
         /// <inheritdoc />
         public IOpenApiSchema? Items { get; set; }
@@ -231,10 +231,10 @@ public string? Minimum
         public JsonNode? Example { get; set; }
 
         /// <inheritdoc />
-        public List<JsonNode>? Examples { get; set; }
+        public IList<JsonNode>? Examples { get; set; }
 
         /// <inheritdoc />
-        public List<JsonNode>? Enum { get; set; }
+        public IList<JsonNode>? Enum { get; set; }
 
         /// <inheritdoc />
         public bool UnevaluatedProperties { get; set; }
@@ -305,7 +305,7 @@ internal OpenApiSchema(IOpenApiSchema schema)
             OneOf = schema.OneOf != null ? [.. schema.OneOf] : null;
             AnyOf = schema.AnyOf != null ? [.. schema.AnyOf] : null;
             Not = schema.Not?.CreateShallowCopy();
-            Required = schema.Required != null ? [.. schema.Required] : null;
+            Required = schema.Required != null ? new HashSet<string>(schema.Required) : null;
             Items = schema.Items?.CreateShallowCopy();
             MaxItems = schema.MaxItems ?? MaxItems;
             MinItems = schema.MinItems ?? MinItems;
@@ -625,7 +625,7 @@ private void WriteFormatProperty(IOpenApiWriter writer)
         /// <param name="propertyName">The property name that will be serialized.</param>
         private void SerializeAsV2(
             IOpenApiWriter writer,
-            HashSet<string>? parentRequiredProperties,
+            ISet<string>? parentRequiredProperties,
             string? propertyName)
         {
             parentRequiredProperties ??= new HashSet<string>();

src/Microsoft.OpenApi/Models/References/OpenApiPathItemReference.cs

@@ -56,10 +56,10 @@ public string? Description
         public Dictionary<HttpMethod, OpenApiOperation>? Operations { get => Target?.Operations; }
 
         /// <inheritdoc/>
-        public List<OpenApiServer>? Servers { get => Target?.Servers; }
+        public IList<OpenApiServer>? Servers { get => Target?.Servers; }
 
         /// <inheritdoc/>
-        public List<IOpenApiParameter>? Parameters { get => Target?.Parameters; }
+        public IList<IOpenApiParameter>? Parameters { get => Target?.Parameters; }
 
         /// <inheritdoc/>
         public IDictionary<string, IOpenApiExtension>? Extensions { get => Target?.Extensions; }

src/Microsoft.OpenApi/Models/References/OpenApiSchemaReference.cs

@@ -88,15 +88,15 @@ public string? Description
         /// <inheritdoc/>
         public bool WriteOnly { get => Target?.WriteOnly ?? false; }
         /// <inheritdoc/>
-        public List<IOpenApiSchema>? AllOf { get => Target?.AllOf; }
+        public IList<IOpenApiSchema>? AllOf { get => Target?.AllOf; }
         /// <inheritdoc/>
-        public List<IOpenApiSchema>? OneOf { get => Target?.OneOf; }
+        public IList<IOpenApiSchema>? OneOf { get => Target?.OneOf; }
         /// <inheritdoc/>
-        public List<IOpenApiSchema>? AnyOf { get => Target?.AnyOf; }
+        public IList<IOpenApiSchema>? AnyOf { get => Target?.AnyOf; }
         /// <inheritdoc/>
         public IOpenApiSchema? Not { get => Target?.Not; }
         /// <inheritdoc/>
-        public HashSet<string>? Required { get => Target?.Required; }
+        public ISet<string>? Required { get => Target?.Required; }
         /// <inheritdoc/>
         public IOpenApiSchema? Items { get => Target?.Items; }
         /// <inheritdoc/>
@@ -122,9 +122,9 @@ public string? Description
         /// <inheritdoc/>
         public JsonNode? Example { get => Target?.Example; }
         /// <inheritdoc/>
-        public List<JsonNode>? Examples { get => Target?.Examples; }
+        public IList<JsonNode>? Examples { get => Target?.Examples; }
         /// <inheritdoc/>
-        public List<JsonNode>? Enum { get => Target?.Enum; }
+        public IList<JsonNode>? Enum { get => Target?.Enum; }
         /// <inheritdoc/>
         public bool UnevaluatedProperties { get => Target?.UnevaluatedProperties ?? false; }
         /// <inheritdoc/>

src/Microsoft.OpenApi/Reader/OpenApiDiagnostic.cs

@@ -15,12 +15,12 @@ public class OpenApiDiagnostic : IDiagnostic
         /// <summary>
         /// List of all errors.
         /// </summary>
-        public List<OpenApiError> Errors { get; set; } = [];
+        public IList<OpenApiError> Errors { get; set; } = [];
 
         /// <summary>
         /// List of all warnings
         /// </summary>
-        public List<OpenApiError> Warnings { get; set; } = [];
+        public IList<OpenApiError> Warnings { get; set; } = [];
 
         /// <summary>
         /// Open API specification version of the document parsed.