fix problem+json context resolving while expanding violation list

package.json

@@ -66,6 +66,7 @@
     "eslint-plugin-tree-shaking": "^1.10.0",
     "jest": "^29.0.0",
     "jest-environment-jsdom": "^29.0.0",
+    "jest-fetch-mock": "^3.0.3",
     "node-fetch": "^3.2.10",
     "playwright": "^1.42.1",
     "prettier": "^3.0.0",

src/hydra/fetchHydra.test.ts

@@ -0,0 +1,96 @@
+import type { HttpError } from 'react-admin';
+import fetchMock from 'jest-fetch-mock';
+import fetchHydra from './fetchHydra.js';
+import schemaAnalyzer from './schemaAnalyzer.js';
+
+fetchMock.enableMocks();
+
+const headers = {
+  'Content-Type': 'application/ld+json; charset=utf-8',
+  Link: '<http://localhost/docs.jsonld>; rel="http://www.w3.org/ns/hydra/core#apiDocumentation"',
+};
+
+test.each([
+  [
+    'ld+json',
+    {
+      '@context': '/contexts/ConstraintViolationList',
+      '@type': 'ConstraintViolationList',
+      'hydra:title': 'An error occurred',
+      'hydra:description':
+        'plainPassword: Password must be at least 6 characters long.',
+      violations: [
+        {
+          propertyPath: 'plainPassword',
+          message: 'Password must be at least 6 characters long.',
+        },
+      ],
+    },
+    { plainPassword: 'Password must be at least 6 characters long.' },
+  ],
+  [
+    'problem+json',
+    {
+      '@id': '\\/validation_errors\\/6b3befbc-2f01-4ddf-be21-b57898905284',
+      '@type': 'ConstraintViolationList',
+      status: 422,
+      violations: [
+        {
+          propertyPath: 'entitlements',
+          message:
+            'At least one product must be selected if policy is restricted.',
+          code: '6b3befbc-2f01-4ddf-be21-b57898905284',
+        },
+      ],
+      detail:
+        'entitlements: At least one product must be selected if policy is restricted.',
+      'hydra:title': 'An error occurred',
+      'hydra:description':
+        'entitlements: At least one product must be selected if policy is restricted.',
+      type: '\\/validation_errors\\/6b3befbc-2f01-4ddf-be21-b57898905284',
+      title: 'An error occurred',
+    },
+    {
+      entitlements:
+        'At least one product must be selected if policy is restricted.',
+    },
+  ],
+])(
+  '%s violation list expanding',
+  async (format: string, resBody: object, expected: object) => {
+    fetchMock.mockResponses(
+      [
+        JSON.stringify(resBody),
+        {
+          status: 422,
+          statusText: '422 Unprocessable Content',
+          headers: {
+            ...headers,
+            'Content-Type': `application/${format}; charset=utf-8`,
+          },
+        },
+      ],
+      [
+        JSON.stringify({
+          '@context': {
+            '@vocab': 'http://localhost/docs.jsonld#',
+            hydra: 'http://www.w3.org/ns/hydra/core#',
+          },
+        }),
+        {
+          status: 200,
+          statusText: 'OK',
+          headers,
+        },
+      ],
+    );
+
+    let violations;
+    try {
+      await fetchHydra(new URL('http://localhost/users'));
+    } catch (error) {
+      violations = schemaAnalyzer().getSubmissionErrors(error as HttpError);
+    }
+    expect(violations).toStrictEqual(expected);
+  },
+);

src/hydra/fetchHydra.ts

@@ -4,7 +4,7 @@ import {
   getDocumentationUrlFromHeaders,
 } from '@api-platform/api-doc-parser';
 import jsonld from 'jsonld';
-import type { NodeObject } from 'jsonld';
+import type { ContextDefinition, NodeObject } from 'jsonld';
 import type { JsonLdObj } from 'jsonld/jsonld-spec';
 import type { HttpClientOptions, HydraHttpClientResponse } from '../types.js';
 
@@ -54,12 +54,20 @@ function fetchHydra(
           return response;
         });
       };
+      const base = getDocumentationUrlFromHeaders(headers);
 
-      return jsonld
-        .expand(body, {
-          base: getDocumentationUrlFromHeaders(headers),
-          documentLoader,
-        })
+      return (
+        '@context' in body
+          ? jsonld.expand(body, {
+              base,
+              documentLoader,
+            })
+          : documentLoader(base).then((response) =>
+              jsonld.expand(body, {
+                expandContext: response.document as ContextDefinition,
+              }),
+            )
+      )
         .then((json) =>
           Promise.reject(
             new HttpError(