Improve code coverage by skipping unreachable code

bkoelman · bkoelman · commit 3ef75b2b763f · 2025-03-24T02:28:46.000+01:00
diff --git a/src/JsonApiDotNetCore.Annotations/ArgumentGuard.cs b/src/JsonApiDotNetCore.Annotations/ArgumentGuard.cs
@@ -1,3 +1,5 @@
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using JetBrains.Annotations;
 using SysNotNull = System.Diagnostics.CodeAnalysis.NotNullAttribute;
@@ -19,4 +21,20 @@ public static void NotNullNorEmpty<T>([SysNotNull] IEnumerable<T>? value, [Calle
             throw new ArgumentException("Collection cannot be null or empty.", parameterName);
         }
     }
+
+    [ExcludeFromCodeCoverage]
+    public static void ThrowUnreachableExceptionIf([DoesNotReturnIf(true)] bool condition)
+    {
+        if (condition)
+        {
+            throw new UnreachableException();
+        }
+    }
+
+    [ExcludeFromCodeCoverage]
+    [DoesNotReturn]
+    public static T ThrowUnreachableException<T>()
+    {
+        throw new UnreachableException();
+    }
 }
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/JsonApiActionDescriptorCollectionProvider.cs b/src/JsonApiDotNetCore.OpenApi.Swashbuckle/JsonApiActionDescriptorCollectionProvider.cs
@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Reflection;
 using JsonApiDotNetCore.Errors;
 using JsonApiDotNetCore.Middleware;
@@ -126,7 +125,7 @@ private static void UpdateProducesResponseTypeAttribute(ActionDescriptor endpoin
             }
         }
 
-        throw new UnreachableException();
+        ArgumentGuard.ThrowUnreachableExceptionIf(true);
     }
 
     private static bool ProducesJsonApiResponseDocument(ActionDescriptor endpoint)
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/JsonApiMetadata/JsonApiEndpointMetadataProvider.cs b/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();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(primaryResourceType == null);
 
         IJsonApiRequestMetadata? requestMetadata = GetRequestMetadata(endpoint, primaryResourceType);
         IJsonApiResponseMetadata? responseMetadata = GetResponseMetadata(endpoint, primaryResourceType);
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/OpenApiEndpointConvention.cs b/src/JsonApiDotNetCore.OpenApi.Swashbuckle/OpenApiEndpointConvention.cs
@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Net;
 using System.Reflection;
 using JsonApiDotNetCore.Configuration;
@@ -109,7 +108,7 @@ private static bool IsEndpointAvailable(JsonApiEndpoints endpoint, ResourceType
             JsonApiEndpoints.PatchRelationship => availableEndpoints.HasFlag(JsonApiEndpoints.PatchRelationship),
             JsonApiEndpoints.Delete => availableEndpoints.HasFlag(JsonApiEndpoints.Delete),
             JsonApiEndpoints.DeleteRelationship => availableEndpoints.HasFlag(JsonApiEndpoints.DeleteRelationship),
-            _ => throw new UnreachableException()
+            _ => ArgumentGuard.ThrowUnreachableException<bool>()
         };
     }
 
@@ -179,7 +178,7 @@ private static HttpStatusCode[] GetSuccessStatusCodesForEndpoint(JsonApiEndpoint
             [
                 HttpStatusCode.NoContent
             ],
-            _ => throw new UnreachableException()
+            _ => ArgumentGuard.ThrowUnreachableException<HttpStatusCode[]>()
         };
     }
 
@@ -238,7 +237,7 @@ private HttpStatusCode[] GetErrorStatusCodesForEndpoint(JsonApiEndpointWrapper e
                 HttpStatusCode.Conflict,
                 HttpStatusCode.UnprocessableEntity
             ],
-            _ => throw new UnreachableException()
+            _ => ArgumentGuard.ThrowUnreachableException<HttpStatusCode[]>()
         };
     }
 
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/OpenApiOperationIdSelector.cs b/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();
-        }
-
+        ArgumentGuard.ThrowUnreachableExceptionIf(!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();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(producesResponseTypeAttribute == null);
 
         ControllerParameterDescriptor? requestBodyDescriptor = endpoint.ActionDescriptor.GetBodyParameterDescriptor();
         Type bodyType = (requestBodyDescriptor?.ParameterType ?? producesResponseTypeAttribute.Type).ConstructedToOpenType();
@@ -95,10 +85,7 @@ 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();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(endpoint.RelativePath == null || endpoint.HttpMethod == null);
 
         string method = endpoint.HttpMethod.ToLowerInvariant();
         string relationshipName = openApiOperationIdTemplate.Contains("[RelationshipName]") ? endpoint.RelativePath.Split('/').Last() : string.Empty;
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/OpenApiSchemaExtensions.cs b/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();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(fullSchema.Properties.Count != propertiesInOrder.Count);
 
         fullSchema.Properties = propertiesInOrder;
     }
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Components/DataContainerSchemaGenerator.cs b/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();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(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();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(!innerPropertyType.IsGenericType);
 
         return innerPropertyType;
     }
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Components/DataSchemaGenerator.cs b/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Components/DataSchemaGenerator.cs
@@ -1,5 +1,4 @@
 using System.Collections.Concurrent;
-using System.Diagnostics;
 using System.Reflection;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.OpenApi.Swashbuckle.JsonApiMetadata;
@@ -199,7 +198,7 @@ public OpenApiSchema GenerateSchema(Type dataSchemaType, bool forRequestSchema,
             return typeof(RelationshipsInResponse);
         }
 
-        throw new UnreachableException();
+        return ArgumentGuard.ThrowUnreachableException<Type?>();
     }
 
     public OpenApiSchema GenerateSchemaForCommonData(Type commonDataSchemaType, SchemaRepository schemaRepository)
@@ -390,11 +389,7 @@ private void SetFieldSchemaMembers(OpenApiSchema fullSchemaForData, ResourceSche
                 GetResourceSchemaTypeForFieldsProperty(resourceSchemaTypeForData, forAttributes ? "Attributes" : "Relationships");
 
             Type? commonFieldsSchemaType = GetCommonSchemaType(resourceSchemaTypeForFields.SchemaOpenType);
-
-            if (commonFieldsSchemaType == null)
-            {
-                throw new UnreachableException();
-            }
+            ArgumentGuard.ThrowUnreachableExceptionIf(commonFieldsSchemaType == null);
 
             _ = GenerateSchemaForCommonFields(commonFieldsSchemaType, schemaRepository);
 
@@ -432,11 +427,7 @@ 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();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(fieldsProperty == null);
 
         Type fieldsConstructedType = fieldsProperty.PropertyType;
         return ResourceSchemaType.Create(fieldsConstructedType, _resourceGraph);
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Components/RelationshipIdentifierSchemaGenerator.cs b/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();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(schemaRepository.TryLookupByType(relationshipIdentifierConstructedType, out _));
 
         OpenApiSchema referenceSchemaForIdentifier = _defaultSchemaGenerator.GenerateSchema(relationshipIdentifierConstructedType, schemaRepository);
         OpenApiSchema fullSchemaForIdentifier = schemaRepository.Schemas[referenceSchemaForIdentifier.Reference.Id];
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Documents/AtomicOperationsDocumentSchemaGenerator.cs b/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/Documents/AtomicOperationsDocumentSchemaGenerator.cs
@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using JsonApiDotNetCore.AtomicOperations;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.Middleware;
@@ -163,7 +162,7 @@ private void GenerateSchemaForResourceOperation(Type operationOpenType, Resource
             AtomicOperationCode.Add => WriteOperationKind.CreateResource,
             AtomicOperationCode.Update => WriteOperationKind.UpdateResource,
             AtomicOperationCode.Remove => WriteOperationKind.DeleteResource,
-            _ => throw new UnreachableException()
+            _ => ArgumentGuard.ThrowUnreachableException<WriteOperationKind>()
         };
 
         if (IsResourceTypeEnabled(resourceType, writeOperation))
@@ -282,7 +281,7 @@ private void GenerateSchemaForRelationshipOperation(Type operationOpenType, Rela
             AtomicOperationCode.Add => WriteOperationKind.AddToRelationship,
             AtomicOperationCode.Update => WriteOperationKind.SetRelationship,
             AtomicOperationCode.Remove => WriteOperationKind.RemoveFromRelationship,
-            _ => throw new UnreachableException()
+            _ => ArgumentGuard.ThrowUnreachableException<WriteOperationKind>()
         };
 
         if (!IsRelationshipEnabled(relationship, writeOperation))
@@ -336,11 +335,7 @@ private void GenerateSchemaForRelationshipOperation(Type operationOpenType, Rela
             RemoveProperties(inlineSchemaForOperation);
 
             string baseRelationshipSchemaId = _schemaIdSelector.GetRelationshipAtomicOperationSchemaId(relationshipInAnyBaseResourceType, operationCode);
-
-            if (!schemaRepository.Schemas.ContainsKey(baseRelationshipSchemaId))
-            {
-                throw new UnreachableException();
-            }
+            ArgumentGuard.ThrowUnreachableExceptionIf(!schemaRepository.Schemas.ContainsKey(baseRelationshipSchemaId));
 
             fullSchemaForOperation.AllOf[0] = new OpenApiSchema
             {
@@ -381,7 +376,7 @@ private static bool IsToOneRelationshipEnabled(HasOneAttribute relationship, Wri
         return writeOperation switch
         {
             WriteOperationKind.SetRelationship => relationship.Capabilities.HasFlag(HasOneCapabilities.AllowSet),
-            _ => throw new UnreachableException()
+            _ => ArgumentGuard.ThrowUnreachableException<bool>()
         };
     }
 
@@ -392,7 +387,7 @@ private static bool IsToManyRelationshipEnabled(HasManyAttribute relationship, W
             WriteOperationKind.SetRelationship => relationship.Capabilities.HasFlag(HasManyCapabilities.AllowSet),
             WriteOperationKind.AddToRelationship => relationship.Capabilities.HasFlag(HasManyCapabilities.AllowAdd),
             WriteOperationKind.RemoveFromRelationship => relationship.Capabilities.HasFlag(HasManyCapabilities.AllowRemove),
-            _ => throw new UnreachableException()
+            _ => ArgumentGuard.ThrowUnreachableException<bool>()
         };
     }
 
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/JsonApiSchemaGenerator.cs b/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SchemaGenerators/JsonApiSchemaGenerator.cs
@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Reflection;
 using JsonApiDotNetCore.Controllers;
 using JsonApiDotNetCore.OpenApi.Swashbuckle.SchemaGenerators.Components;
@@ -62,6 +61,6 @@ private DocumentSchemaGenerator GetDocumentSchemaGenerator(Type schemaType)
             }
         }
 
-        throw new UnreachableException();
+        return ArgumentGuard.ThrowUnreachableException<DocumentSchemaGenerator>();
     }
 }
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SwaggerComponents/DocumentationOpenApiOperationFilter.cs b/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();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(apiDescription.RelativePath == null);
 
         string relationshipName = apiDescription.RelativePath.Split('/').Last();
         return resourceType.GetRelationshipByPublicName(relationshipName);
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SwaggerComponents/ResourceFieldSchemaBuilder.cs b/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SwaggerComponents/ResourceFieldSchemaBuilder.cs
@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Reflection;
 using JsonApiDotNetCore.OpenApi.Swashbuckle.JsonApiMetadata;
 using JsonApiDotNetCore.OpenApi.Swashbuckle.JsonApiObjects.ResourceObjects;
@@ -110,7 +109,7 @@ private static AttrCapabilities GetRequiredCapabilityForAttributes(Type resource
     {
         return resourceDataOpenType == typeof(DataInResponse<>) ? AttrCapabilities.AllowView :
             resourceDataOpenType == typeof(DataInCreateRequest<>) ? AttrCapabilities.AllowCreate :
-            resourceDataOpenType == typeof(DataInUpdateRequest<>) ? AttrCapabilities.AllowChange : throw new UnreachableException();
+            resourceDataOpenType == typeof(DataInUpdateRequest<>) ? AttrCapabilities.AllowChange : ArgumentGuard.ThrowUnreachableException<AttrCapabilities>();
     }
 
     private void EnsureAttributeSchemaIsExposed(OpenApiSchema referenceSchemaForAttribute, AttrAttribute attribute, SchemaRepository schemaRepository)
@@ -221,9 +220,6 @@ private OpenApiSchema CreateReferenceSchemaForRelationship(Type relationshipSche
 
     private static void AssertHasNoProperties(OpenApiSchema fullSchema)
     {
-        if (fullSchema.Properties.Count > 0)
-        {
-            throw new UnreachableException();
-        }
+        ArgumentGuard.ThrowUnreachableExceptionIf(fullSchema.Properties.Count > 0);
     }
 }
diff --git a/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SwaggerComponents/StringEnumOrderingFilter.cs b/src/JsonApiDotNetCore.OpenApi.Swashbuckle/SwaggerComponents/StringEnumOrderingFilter.cs
@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using JetBrains.Annotations;
 using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Interfaces;
@@ -47,11 +46,7 @@ private static bool HasSortAnnotation(OpenApiSchema schema)
         private static void OrderEnumMembers(OpenApiSchema schema)
         {
             List<IOpenApiAny> ordered = schema.Enum.OfType<OpenApiString>().OrderBy(openApiString => openApiString.Value).Cast<IOpenApiAny>().ToList();
-
-            if (ordered.Count != schema.Enum.Count)
-            {
-                throw new UnreachableException();
-            }
+            ArgumentGuard.ThrowUnreachableExceptionIf(ordered.Count != schema.Enum.Count);
 
             schema.Enum = ordered;
         }

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,3 @@`
`1`		`-using System.Diagnostics;`
`2`	`1`	`using System.Reflection;`
`3`	`2`	`using JsonApiDotNetCore.Errors;`
`4`	`3`	`using JsonApiDotNetCore.Middleware;`
`@@ -126,7 +125,7 @@ private static void UpdateProducesResponseTypeAttribute(ActionDescriptor endpoin`
`126`	`125`	`}`
`127`	`126`	`}`
`128`	`127`
`129`		`- throw new UnreachableException();`
	`128`	`+ ArgumentGuard.ThrowUnreachableExceptionIf(true);`
`130`	`129`	`}`
`131`	`130`
`132`	`131`	`private static bool ProducesJsonApiResponseDocument(ActionDescriptor endpoint)`
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,3 @@`
`1`		`-using System.Diagnostics;`
`2`	`1`	`using Microsoft.OpenApi.Models;`
`3`	`2`
`4`	`3`	`namespace JsonApiDotNetCore.OpenApi.Swashbuckle;`
`@@ -20,10 +19,7 @@ public static void ReorderProperties(this OpenApiSchema fullSchema, IEnumerable<`
`20`	`19`	`}`
`21`	`20`	`}`
`22`	`21`
`23`		`- if (fullSchema.Properties.Count != propertiesInOrder.Count)`
`24`		`- {`
`25`		`- throw new UnreachableException();`
`26`		`- }`
	`22`	`+ ArgumentGuard.ThrowUnreachableExceptionIf(fullSchema.Properties.Count != propertiesInOrder.Count);`
`27`	`23`
`28`	`24`	`fullSchema.Properties = propertiesInOrder;`
`29`	`25`	`}`