fix: more specific errors

Author: wtrocki

tools/spectral/ipa/__tests__/IPA125OneOfMustHaveDiscriminator.test.js

@@ -94,7 +94,74 @@ testRule('xgen-IPA-125-oneOf-must-have-discriminator', [
     errors: [
       {
         code: 'xgen-IPA-125-oneOf-must-have-discriminator',
-        message: 'Each oneOf property must include a discriminator property to define the exact type.',
+        message: 'The schema has oneOf but no discriminator property.',
+        path: ['schemas', 'Animal'],
+        severity: DiagnosticSeverity.Error,
+      },
+    ],
+  },
+  {
+    name: 'invalid oneOf with non-object discriminator',
+    document: {
+      components: componentSchemas,
+      schemas: {
+        Animal: {
+          oneOf: [{ $ref: '#/components/schemas/Dog' }, { $ref: '#/components/schemas/Cat' }],
+          discriminator: "I'm a string, not an object!",
+        },
+      },
+    },
+    errors: [
+      {
+        code: 'xgen-IPA-125-oneOf-must-have-discriminator',
+        message: 'Discriminator property is not an object.',
+        path: ['schemas', 'Animal'],
+        severity: DiagnosticSeverity.Error,
+      },
+    ],
+  },
+  {
+    name: 'invalid oneOf with discriminator but no propertyName',
+    document: {
+      components: componentSchemas,
+      schemas: {
+        Animal: {
+          oneOf: [{ $ref: '#/components/schemas/Dog' }, { $ref: '#/components/schemas/Cat' }],
+          discriminator: {
+            mapping: {
+              dog: '#/components/schemas/Dog',
+              cat: '#/components/schemas/Cat',
+            },
+          },
+        },
+      },
+    },
+    errors: [
+      {
+        code: 'xgen-IPA-125-oneOf-must-have-discriminator',
+        message: 'Discriminator has no propertyName defined.',
+        path: ['schemas', 'Animal'],
+        severity: DiagnosticSeverity.Error,
+      },
+    ],
+  },
+  {
+    name: 'invalid oneOf with discriminator but no mapping',
+    document: {
+      components: componentSchemas,
+      schemas: {
+        Animal: {
+          oneOf: [{ $ref: '#/components/schemas/Dog' }, { $ref: '#/components/schemas/Cat' }],
+          discriminator: {
+            propertyName: 'type',
+          },
+        },
+      },
+    },
+    errors: [
+      {
+        code: 'xgen-IPA-125-oneOf-must-have-discriminator',
+        message: 'Discriminator must have a mapping object.',
         path: ['schemas', 'Animal'],
         severity: DiagnosticSeverity.Error,
       },

tools/spectral/ipa/rulesets/functions/IPA125OneOfMustHaveDiscriminator.js

@@ -3,7 +3,11 @@ import { resolveObject } from './utils/componentUtils.js';
 import { hasException } from './utils/exceptions.js';
 
 const RULE_NAME = 'xgen-IPA-125-oneOf-must-have-discriminator';
-const ERROR_MESSAGE = 'Each oneOf property must include a discriminator property to define the exact type.';
+const GENERIC_ERROR_MESSAGE = 'Each oneOf property must include a discriminator property to define the exact type.';
+const MISSING_DISCRIMINATOR_MESSAGE = 'The schema has oneOf but no discriminator property.';
+const INVALID_DISCRIMINATOR_MESSAGE = 'Discriminator property is not an object.';
+const MISSING_PROPERTY_NAME_MESSAGE = 'Discriminator has no propertyName defined.';
+const MISSING_MAPPING_MESSAGE = 'Discriminator must have a mapping object.';
 const MAPPING_ERROR_MESSAGE =
   'The discriminator mapping must match the oneOf references. Unmatched Discriminator mappings with oneOf references:';
 
@@ -26,13 +30,21 @@ export default (input, _, { path, documentInventory }) => {
     return;
   }
 
-  // Validate the presence of a discriminator
-  if (!schema.discriminator || typeof schema.discriminator !== 'object' || !schema.discriminator.propertyName) {
-    return collectAndReturnViolation(path, RULE_NAME, [{ message: ERROR_MESSAGE }]);
+  // Validate the presence of a discriminator with more specific error messages
+  if (!schema.discriminator) {
+    return collectAndReturnViolation(path, RULE_NAME, [{ message: MISSING_DISCRIMINATOR_MESSAGE }]);
+  }
+
+  if (typeof schema.discriminator !== 'object') {
+    return collectAndReturnViolation(path, RULE_NAME, [{ message: INVALID_DISCRIMINATOR_MESSAGE }]);
+  }
+
+  if (!schema.discriminator.propertyName) {
+    return collectAndReturnViolation(path, RULE_NAME, [{ message: MISSING_PROPERTY_NAME_MESSAGE }]);
   }
 
   if (!schema.discriminator.mapping) {
-    return collectAndReturnViolation(path, RULE_NAME, [{ message: ERROR_MESSAGE }]);
+    return collectAndReturnViolation(path, RULE_NAME, [{ message: MISSING_MAPPING_MESSAGE }]);
   }
 
   const oneOfRefs = schema.oneOf.map((item) => item.$ref);