Improve code coverage by skipping unreachable code

Author: bkoelman

src/JsonApiDotNetCore.OpenApi.Swashbuckle/ConsistencyGuard.cs

@@ -0,0 +1,18 @@
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+
+namespace JsonApiDotNetCore.OpenApi.Swashbuckle;
+
+#pragma warning disable AV1008 // Class should not be static
+
+internal static class ConsistencyGuard
+{
+    [ExcludeFromCodeCoverage]
+    public static void ThrowIf([DoesNotReturnIf(true)] bool condition)
+    {
+        if (condition)
+        {
+            throw new UnreachableException();
+        }
+    }
+}

src/JsonApiDotNetCore.OpenApi.Swashbuckle/JsonApiMetadata/JsonApiEndpointMetadataProvider.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Reflection;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.Controllers;
@@ -43,11 +42,7 @@ public JsonApiEndpointMetadataContainer Get(MethodInfo controllerAction)
         }
 
         ResourceType? primaryResourceType = _controllerResourceMapping.GetResourceTypeForController(controllerAction.ReflectedType);
-
-        if (primaryResourceType == null)
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(primaryResourceType == null);
 
         IJsonApiRequestMetadata? requestMetadata = GetRequestMetadata(endpoint, primaryResourceType);
         IJsonApiResponseMetadata? responseMetadata = GetResponseMetadata(endpoint, primaryResourceType);

src/JsonApiDotNetCore.OpenApi.Swashbuckle/OpenApiOperationIdSelector.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Reflection;
 using System.Text.Json;
 using Humanizer;
@@ -64,23 +63,14 @@ public string GetOpenApiOperationId(ApiDescription endpoint)
     private static string GetTemplate(ApiDescription endpoint)
     {
         Type bodyType = GetBodyType(endpoint);
-
-        if (!SchemaOpenTypeToOpenApiOperationIdTemplateMap.TryGetValue(bodyType, out string? template))
-        {
-            throw new UnreachableException();
-        }
-
+        ConsistencyGuard.ThrowIf(!SchemaOpenTypeToOpenApiOperationIdTemplateMap.TryGetValue(bodyType, out string? template));
         return template;
     }
 
     private static Type GetBodyType(ApiDescription endpoint)
     {
         var producesResponseTypeAttribute = endpoint.ActionDescriptor.GetFilterMetadata<ProducesResponseTypeAttribute>();
-
-        if (producesResponseTypeAttribute == null)
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(producesResponseTypeAttribute == null);
 
         ControllerParameterDescriptor? requestBodyDescriptor = endpoint.ActionDescriptor.GetBodyParameterDescriptor();
         Type bodyType = (requestBodyDescriptor?.ParameterType ?? producesResponseTypeAttribute.Type).ConstructedToOpenType();
@@ -95,10 +85,8 @@ private static Type GetBodyType(ApiDescription endpoint)
 
     private string ApplyTemplate(string openApiOperationIdTemplate, ResourceType? resourceType, ApiDescription endpoint)
     {
-        if (endpoint.RelativePath == null || endpoint.HttpMethod == null)
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(endpoint.RelativePath == null);
+        ConsistencyGuard.ThrowIf(endpoint.HttpMethod == null);
 
         string method = endpoint.HttpMethod.ToLowerInvariant();
         string relationshipName = openApiOperationIdTemplate.Contains("[RelationshipName]") ? endpoint.RelativePath.Split('/').Last() : string.Empty;

src/JsonApiDotNetCore.OpenApi.Swashbuckle/OpenApiSchemaExtensions.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using Microsoft.OpenApi.Models;
 
 namespace JsonApiDotNetCore.OpenApi.Swashbuckle;
@@ -20,10 +19,7 @@ public static void ReorderProperties(this OpenApiSchema fullSchema, IEnumerable<
             }
         }
 
-        if (fullSchema.Properties.Count != propertiesInOrder.Count)
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(fullSchema.Properties.Count != propertiesInOrder.Count);
 
         fullSchema.Properties = propertiesInOrder;
     }

src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Components/DataContainerSchemaGenerator.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Reflection;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.OpenApi.Swashbuckle.JsonApiObjects.ResourceObjects;
@@ -64,11 +63,7 @@ public OpenApiSchema GenerateSchema(Type dataContainerSchemaType, ResourceType r
     private static Type GetElementTypeOfDataProperty(Type dataContainerConstructedType, ResourceType resourceType)
     {
         PropertyInfo? dataProperty = dataContainerConstructedType.GetProperty("Data");
-
-        if (dataProperty == null)
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(dataProperty == null);
 
         Type innerPropertyType = dataProperty.PropertyType.ConstructedToOpenType().IsAssignableTo(typeof(ICollection<>))
             ? dataProperty.PropertyType.GenericTypeArguments[0]
@@ -79,10 +74,7 @@ private static Type GetElementTypeOfDataProperty(Type dataContainerConstructedTy
             return typeof(DataInResponse<>).MakeGenericType(resourceType.ClrType);
         }
 
-        if (!innerPropertyType.IsGenericType)
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(!innerPropertyType.IsGenericType);
 
         return innerPropertyType;
     }

src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Components/DataSchemaGenerator.cs

@@ -390,11 +390,7 @@ private void SetFieldSchemaMembers(OpenApiSchema fullSchemaForData, ResourceSche
                 GetResourceSchemaTypeForFieldsProperty(resourceSchemaTypeForData, forAttributes ? "Attributes" : "Relationships");
 
             Type? commonFieldsSchemaType = GetCommonSchemaType(resourceSchemaTypeForFields.SchemaOpenType);
-
-            if (commonFieldsSchemaType == null)
-            {
-                throw new UnreachableException();
-            }
+            ConsistencyGuard.ThrowIf(commonFieldsSchemaType == null);
 
             _ = GenerateSchemaForCommonFields(commonFieldsSchemaType, schemaRepository);
 
@@ -432,11 +428,7 @@ private void SetFieldSchemaMembers(OpenApiSchema fullSchemaForData, ResourceSche
     private ResourceSchemaType GetResourceSchemaTypeForFieldsProperty(ResourceSchemaType resourceSchemaTypeForData, string propertyName)
     {
         PropertyInfo? fieldsProperty = resourceSchemaTypeForData.SchemaConstructedType.GetProperty(propertyName);
-
-        if (fieldsProperty == null)
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(fieldsProperty == null);
 
         Type fieldsConstructedType = fieldsProperty.PropertyType;
         return ResourceSchemaType.Create(fieldsConstructedType, _resourceGraph);

src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Components/RelationshipIdentifierSchemaGenerator.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.OpenApi.Swashbuckle.JsonApiObjects.ResourceObjects;
 using JsonApiDotNetCore.Resources.Annotations;
@@ -52,11 +51,7 @@ public OpenApiSchema GenerateSchema(RelationshipAttribute relationship, SchemaRe
         }
 
         Type relationshipIdentifierConstructedType = typeof(RelationshipIdentifier<>).MakeGenericType(relationship.LeftType.ClrType);
-
-        if (schemaRepository.TryLookupByType(relationshipIdentifierConstructedType, out _))
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(schemaRepository.TryLookupByType(relationshipIdentifierConstructedType, out _));
 
         OpenApiSchema referenceSchemaForIdentifier = _defaultSchemaGenerator.GenerateSchema(relationshipIdentifierConstructedType, schemaRepository);
         OpenApiSchema fullSchemaForIdentifier = schemaRepository.Schemas[referenceSchemaForIdentifier.Reference.Id];

src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Documents/AtomicOperationsDocumentSchemaGenerator.cs

@@ -336,11 +336,7 @@ private void GenerateSchemaForRelationshipOperation(Type operationOpenType, Rela
             RemoveProperties(inlineSchemaForOperation);
 
             string baseRelationshipSchemaId = _schemaIdSelector.GetRelationshipAtomicOperationSchemaId(relationshipInAnyBaseResourceType, operationCode);
-
-            if (!schemaRepository.Schemas.ContainsKey(baseRelationshipSchemaId))
-            {
-                throw new UnreachableException();
-            }
+            ConsistencyGuard.ThrowIf(!schemaRepository.Schemas.ContainsKey(baseRelationshipSchemaId));
 
             fullSchemaForOperation.AllOf[0] = new OpenApiSchema
             {

src/JsonApiDotNetCore.OpenApi.Swashbuckle/SwaggerComponents/DocumentationOpenApiOperationFilter.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Net;
 using System.Reflection;
 using Humanizer;
@@ -439,10 +438,7 @@ private void ApplyDeleteRelationship(OpenApiOperation operation, RelationshipAtt
 
     private static RelationshipAttribute GetRelationshipFromRoute(ApiDescription apiDescription, ResourceType resourceType)
     {
-        if (apiDescription.RelativePath == null)
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(apiDescription.RelativePath == null);
 
         string relationshipName = apiDescription.RelativePath.Split('/').Last();
         return resourceType.GetRelationshipByPublicName(relationshipName);

src/JsonApiDotNetCore.OpenApi.Swashbuckle/SwaggerComponents/ResourceFieldSchemaBuilder.cs

@@ -221,9 +221,6 @@ private OpenApiSchema CreateReferenceSchemaForRelationship(Type relationshipSche
 
     private static void AssertHasNoProperties(OpenApiSchema fullSchema)
     {
-        if (fullSchema.Properties.Count > 0)
-        {
-            throw new UnreachableException();
-        }
+        ConsistencyGuard.ThrowIf(fullSchema.Properties.Count > 0);
     }
 }