From 33831144a4cd1a57355f4c7f981264a2d7c8d09d Mon Sep 17 00:00:00 2001
From: Dustin Popp <dpopp07@gmail.com>
Date: Tue, 27 Aug 2019 08:51:48 -0500
Subject: [PATCH] fix: treat response schemas with an `items` field as arrays,
 even if there is no `type` (#99)

---
 .../semantic-validators/operations-shared.js  | 12 ++-
 .../validation/2and3/operations-shared.js     | 85 +++++++++++++++++++
 2 files changed, 95 insertions(+), 2 deletions(-)

diff --git a/src/plugins/validation/2and3/semantic-validators/operations-shared.js b/src/plugins/validation/2and3/semantic-validators/operations-shared.js
index aade9e384..b397558af 100644
--- a/src/plugins/validation/2and3/semantic-validators/operations-shared.js
+++ b/src/plugins/validation/2and3/semantic-validators/operations-shared.js
@@ -72,7 +72,11 @@ module.exports.validate = function({ resolvedSpec, isOAS3 }, config) {
         each(op.responses, (response, name) => {
           if (isOAS3) {
             each(response.content, (content, contentType) => {
-              if (content.schema && content.schema.type === 'array') {
+              const isArray =
+                content.schema &&
+                (content.schema.type === 'array' || content.schema.items);
+
+              if (isArray) {
                 result[checkStatusArrRes].push({
                   path: `paths.${pathKey}.${opKey}.responses.${name}.content.${contentType}.schema`,
                   message:
@@ -81,7 +85,11 @@ module.exports.validate = function({ resolvedSpec, isOAS3 }, config) {
               }
             });
           } else {
-            if (response.schema && response.schema.type === 'array') {
+            const isArray =
+              response.schema &&
+              (response.schema.type === 'array' || response.schema.items);
+
+            if (isArray) {
               result[checkStatusArrRes].push({
                 path: `paths.${pathKey}.${opKey}.responses.${name}.schema`,
                 message:
diff --git a/test/plugins/validation/2and3/operations-shared.js b/test/plugins/validation/2and3/operations-shared.js
index ff6694444..9e8364db9 100644
--- a/test/plugins/validation/2and3/operations-shared.js
+++ b/test/plugins/validation/2and3/operations-shared.js
@@ -293,6 +293,40 @@ describe('validation plugin - semantic - operations-shared', function() {
       expect(res.warnings.length).toEqual(0);
     });
 
+    it('should complain about an anonymous array response model with no type but an `items` field', function() {
+      const spec = {
+        paths: {
+          '/stuff': {
+            get: {
+              summary: 'list stuff',
+              operationId: 'list_stuff',
+              produces: ['application/json'],
+              responses: {
+                200: {
+                  description: 'successful operation',
+                  schema: {
+                    items: {
+                      type: 'string'
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      };
+
+      const res = validate({ resolvedSpec: spec }, config);
+      expect(res.errors.length).toEqual(1);
+      expect(res.errors[0].path).toEqual(
+        'paths./stuff.get.responses.200.schema'
+      );
+      expect(res.errors[0].message).toEqual(
+        'Arrays MUST NOT be returned as the top-level structure in a response body.'
+      );
+      expect(res.warnings.length).toEqual(0);
+    });
+
     it('should not complain about an empty summary within a vendor extension', function() {
       const spec = {
         paths: {
@@ -726,6 +760,57 @@ describe('validation plugin - semantic - operations-shared', function() {
       expect(res.warnings.length).toEqual(0);
     });
 
+    it('should complain about a top-level array response without a type but with an `items` field', function() {
+      const spec = {
+        paths: {
+          '/': {
+            put: {
+              operationId: 'get_everything',
+              summary: 'get everything as a string or an array',
+              requestBody: {
+                description: 'simple body',
+                content: {
+                  'application/json': {
+                    schema: {
+                      type: 'string'
+                    }
+                  }
+                }
+              },
+              responses: {
+                '200': {
+                  content: {
+                    'text/plain': {
+                      schema: {
+                        type: 'string'
+                      }
+                    },
+                    'application/json': {
+                      schema: {
+                        items: {
+                          type: 'string'
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      };
+
+      const res = validate({ resolvedSpec: spec, isOAS3: true }, config);
+      expect(res.errors.length).toEqual(1);
+      expect(res.errors[0].path).toEqual(
+        'paths./.put.responses.200.content.application/json.schema'
+      );
+      expect(res.errors[0].message).toEqual(
+        'Arrays MUST NOT be returned as the top-level structure in a response body.'
+      );
+      expect(res.warnings.length).toEqual(0);
+    });
+
     it('should complain about an unused tag', function() {
       const spec = {
         tags: [