fix: properly handle circular regressions to prevent call stack excep…

…tions (#253)

A regression was recently introduced to the validator in the circular references
utility that prevented such references from being caught and sanitized. This resulted
in "call stack exceeded" expections for certain patterns using circular references.

The regression came in the form of checking for only "plain" objects, rather than
all "objects" (which include arrays). This happened in a recent community PR and I
didn't realize the consequences when I reviewed and merged. I went back and double
checked every instance of this change in that PR and believe this is the only one
that is problematic. I fixed it and added a new test case that would've caught this
regression had it been there.

src/cli-validator/utils/circular-references-ibm.js

@@ -2,6 +2,7 @@
 // correct them,
 
 const isPlainObject = require('lodash/isPlainObject');
+const isObject = require('lodash/isObject');
 
 // and return them as problems if applicable
 const validate = function({ jsSpec, resolvedSpec }, config) {
@@ -29,7 +30,8 @@ const correctSpec = function(resolvedSpec) {
       return null;
     }
 
-    if (!isPlainObject(object)) {
+    // we need to catch arrays here, in addition to plain objects
+    if (!isObject(object)) {
       return null;
     }
 

test/cli-validator/mockFiles/composite-pattern.yaml

@@ -0,0 +1,29 @@
+openapi: '3.0.2'
+info:
+  title: Repro "call stack" error
+  description: Reproduce the "Maximum call stack size exceeded" error with Composite-pattern schemas
+  version: '0.1.0'
+paths:
+  /example:
+    post:
+      summary: Just an example path
+      description: Just an example path to make this a valid spec
+      operationId: postExample
+components:
+  schemas:
+    Pair:
+      description: A pair of two elements or pairs or both
+      type: object
+      properties:
+        a:
+          oneOf:
+            - $ref: "#/components/schemas/Element"
+            - $ref: "#/components/schemas/Pair"
+        b:
+          oneOf:
+            - $ref: "#/components/schemas/Element"
+            - $ref: "#/components/schemas/Pair"
+    Element:
+      description: An elemental numeric value
+      type: number
+      example: 42

test/cli-validator/tests/circular-refs-validator.test.js

@@ -63,4 +63,27 @@ describe('cli tool - test circular reference module', function() {
     const realPath = circularRefsValidator.convert(testObject, resolvedPaths);
     expect(realPath[0]).toEqual('definitions.something.foo');
   });
+
+  it('should correctly validate a file using the composite pattern', async function() {
+    const consoleSpy = jest.spyOn(console, 'log').mockImplementation(() => {});
+
+    const program = {};
+    program.args = ['./test/cli-validator/mockFiles/composite-pattern.yaml'];
+    program.default_mode = true;
+
+    const exitCode = await commandLineValidator(program);
+
+    const capturedText = getCapturedText(consoleSpy.mock.calls);
+    consoleSpy.mockRestore();
+
+    expect(exitCode).toEqual(0);
+
+    const allOutput = capturedText.join('');
+
+    expect(
+      allOutput.includes(
+        'Swagger object should not contain circular references.'
+      )
+    ).toEqual(true);
+  });
 });