Backport of #420

Sources/OpenAPIKit/Validator/Validation+Builtins.swift

@@ -408,6 +408,28 @@ extension Validation {
         )
     }
 
+    /// Validate that all non-external Callbacks references are found in the document's
+    /// components dictionary.
+    ///
+    /// - Important: This is included in validation by default.
+    ///
+    public static var callbacksReferencesAreValid: Validation<OpenAPI.Reference<OpenAPI.Callbacks>> {
+        .init(
+            description: "Callbacks reference can be found in components/callbacks",
+            check: { context in
+                guard case let .internal(internalReference) = context.subject.jsonReference,
+                      case .component = internalReference else {
+                        // don't make assertions about external references
+                        // TODO: could make a stronger assertion including
+                        // internal references outside of components given
+                        // some way to resolve those references.
+                        return true
+                }
+                return context.document.components.contains(internalReference)
+            }
+        )
+    }
+
     /// Validate that all non-external PathItem references are found in the document's
     /// components dictionary.
     ///

Sources/OpenAPIKit/Validator/Validator.swift

@@ -190,6 +190,7 @@ public final class Validator {
             .init(.requestReferencesAreValid),
             .init(.headerReferencesAreValid),
             .init(.linkReferencesAreValid),
+            .init(.callbacksReferencesAreValid),
             .init(.pathItemReferencesAreValid),
             .init(.serverVariableEnumIsValid),
             .init(.serverVariableDefaultExistsInEnum)

Sources/OpenAPIKit30/Validator/Validation+Builtins.swift

@@ -397,6 +397,28 @@ extension Validation {
         )
     }
 
+    /// Validate that all non-external Callbacks references are found in the document's
+    /// components dictionary.
+    ///
+    /// - Important: This is included in validation by default.
+    ///
+    public static var callbacksReferencesAreValid: Validation<JSONReference<OpenAPI.Callbacks>> {
+        .init(
+            description: "Callbacks reference can be found in components/callbacks",
+            check: { context in
+                guard case let .internal(internalReference) = context.subject,
+                      case .component = internalReference else {
+                        // don't make assertions about external references
+                        // TODO: could make a stronger assertion including
+                        // internal references outside of components given
+                        // some way to resolve those references.
+                        return true
+                }
+                return context.document.components.contains(internalReference)
+            }
+        )
+    }
+
     /// Validate the OpenAPI Document's `Links` with operationIds refer to
     /// Operations that exist in the document.
     ///

Sources/OpenAPIKit30/Validator/Validator.swift

@@ -186,7 +186,8 @@ public final class Validator {
             .init(.exampleReferencesAreValid),
             .init(.requestReferencesAreValid),
             .init(.headerReferencesAreValid),
-            .init(.linkReferencesAreValid)
+            .init(.linkReferencesAreValid),
+            .init(.callbacksReferencesAreValid)
         ])
     }
 

Tests/OpenAPIKit30Tests/Validator/BuiltinValidationTests.swift

@@ -638,6 +638,9 @@ final class BuiltinValidationTests: XCTestCase {
                         ],
                         links: ["linky": .reference(.component(named: "link1"))]
                     )
+                ],
+                callbacks: [
+                  "callbacks1": .reference(.component(named: "callbacks1"))
                 ]
             )
         )
@@ -654,7 +657,7 @@ final class BuiltinValidationTests: XCTestCase {
         // NOTE this is part of default validation
         XCTAssertThrowsError(try document.validate()) { error in
             let error = error as? ValidationErrorCollection
-            XCTAssertEqual(error?.values.count, 7)
+            XCTAssertEqual(error?.values.count, 8)
             XCTAssertEqual(error?.values[0].reason, "Failed to satisfy: Parameter reference can be found in components/parameters")
             XCTAssertEqual(error?.values[0].codingPathString, ".paths['/hello'].get.parameters[0]")
             XCTAssertEqual(error?.values[1].reason, "Failed to satisfy: Request reference can be found in components/requestBodies")
@@ -669,6 +672,8 @@ final class BuiltinValidationTests: XCTestCase {
             XCTAssertEqual(error?.values[5].codingPathString, ".paths['/hello'].get.responses.404.content['application/xml'].schema")
             XCTAssertEqual(error?.values[6].reason, "Failed to satisfy: Link reference can be found in components/links")
             XCTAssertEqual(error?.values[6].codingPathString, ".paths['/hello'].get.responses.404.links.linky")
+            XCTAssertEqual(error?.values[7].reason, "Failed to satisfy: Callbacks reference can be found in components/callbacks")
+            XCTAssertEqual(error?.values[7].codingPathString, ".paths['/hello'].get.callbacks.callbacks1")
         }
     }
 
@@ -711,6 +716,9 @@ final class BuiltinValidationTests: XCTestCase {
                             "linky2": .reference(.external(URL(string: "https://linky.com")!))
                         ]
                     )
+                ],
+                callbacks: [
+                  "callbacks1": .reference(.component(named: "callbacks1"))
                 ]
             )
         )
@@ -742,6 +750,9 @@ final class BuiltinValidationTests: XCTestCase {
                 ],
                 links: [
                     "link1": .init(operationId: "op 1")
+                ],
+                callbacks: [
+                  "callbacks1": .init()
                 ]
             )
         )

Tests/OpenAPIKitCompatTests/DocumentConversionTests.swift

@@ -202,6 +202,9 @@ final class DocumentConversionTests: XCTestCase {
             components: .init(
                 parameters: [
                     "test": .init(name: "referencedParam", context: .query, schema: .string)
+                ],
+                callbacks: [
+                  "other_callback": callbacks
                 ]
             )
         )

Tests/OpenAPIKitTests/Validator/BuiltinValidationTests.swift

@@ -741,6 +741,9 @@ final class BuiltinValidationTests: XCTestCase {
                         ],
                         links: ["linky": .reference(.component(named: "link1"))]
                     )
+                ],
+                callbacks: [
+                  "callbacks1": .reference(.component(named: "callbacks1"))
                 ]
             )
         )
@@ -758,7 +761,7 @@ final class BuiltinValidationTests: XCTestCase {
         // NOTE this is part of default validation
         XCTAssertThrowsError(try document.validate()) { error in
             let error = error as? ValidationErrorCollection
-            XCTAssertEqual(error?.values.count, 8)
+            XCTAssertEqual(error?.values.count, 9)
             XCTAssertEqual(error?.values[0].reason, "Failed to satisfy: Parameter reference can be found in components/parameters")
             XCTAssertEqual(error?.values[0].codingPathString, ".paths['/hello'].get.parameters[0]")
             XCTAssertEqual(error?.values[1].reason, "Failed to satisfy: Request reference can be found in components/requestBodies")
@@ -773,8 +776,10 @@ final class BuiltinValidationTests: XCTestCase {
             XCTAssertEqual(error?.values[5].codingPathString, ".paths['/hello'].get.responses.404.content['application/xml'].schema")
             XCTAssertEqual(error?.values[6].reason, "Failed to satisfy: Link reference can be found in components/links")
             XCTAssertEqual(error?.values[6].codingPathString, ".paths['/hello'].get.responses.404.links.linky")
-            XCTAssertEqual(error?.values[7].reason, "Failed to satisfy: PathItem reference can be found in components/pathItems")
-            XCTAssertEqual(error?.values[7].codingPathString, ".paths['/world']")
+            XCTAssertEqual(error?.values[7].reason, "Failed to satisfy: Callbacks reference can be found in components/callbacks")
+            XCTAssertEqual(error?.values[7].codingPathString, ".paths['/hello'].get.callbacks.callbacks1")
+            XCTAssertEqual(error?.values[8].reason, "Failed to satisfy: PathItem reference can be found in components/pathItems")
+            XCTAssertEqual(error?.values[8].codingPathString, ".paths['/world']")
         }
     }
 
@@ -817,6 +822,9 @@ final class BuiltinValidationTests: XCTestCase {
                             "linky2": .reference(.external(URL(string: "https://linky.com")!))
                         ]
                     )
+                ],
+                callbacks: [
+                  "callbacks1": .reference(.component(named: "callbacks1"))
                 ]
             )
         )
@@ -851,6 +859,9 @@ final class BuiltinValidationTests: XCTestCase {
                 links: [
                     "link1": .init(operationId: "op 1")
                 ],
+                callbacks: [
+                  "callbacks1": .init()
+                ],
                 pathItems: [
                     "path1": .init()
                 ]