Add testcase to confirm current link behaviour and add check if 'link' in options is instance of dict.

CHANGELOG.md

@@ -8,6 +8,7 @@
 - An empty property-scoped context no longer resets the active context in `_create_term_definition`. Now only explicit null becomes False; empty contexts are preserved. Fixes [compact#tc028](https://w3c.github.io/json-ld-api/tests/compact-manifest.html#tc028), [toRdf#tc036](https://w3c.github.io/json-ld-api/tests/toRdf-manifest.html#tc036) and [expand#tc036](https://w3c.github.io/json-ld-api/tests/expand-manifest.html#tc036).
 - Options from the test manifest now override the options configured in `create_test_options()`, instead of the other way around. This fixes tests not able to override default options in the test-setup such as `extractAllScripts`. Fixes [html#tf004](https://w3c.github.io/json-ld-api/tests/html-manifest#tf004).
 - When `@type` is `@json` in a frame, it no longer raises an "Invalid JSON-LD syntax" error. Fixes [frame#t0069](https://w3c.github.io/json-ld-framing/tests/frame-manifest.html#t0069).
+- Use safeguard for non-dict values of `options['link']`
 
 ### Added
 - `pyld.DocumentLoader` abstract base class for class-based document loaders,

lib/pyld/jsonld.py

@@ -1496,7 +1496,8 @@ def _compact(self, active_ctx, active_property, element, options):
         # recursively compact object
         if _is_object(element):
             if (
-                options['link']
+                isinstance(options['link'], dict)
+                and options['link']
                 and '@id' in element
                 and element['@id'] in options['link']
             ):
@@ -1511,7 +1512,7 @@ def _compact(self, active_ctx, active_property, element, options):
                 rval = self._compact_value(
                     active_ctx, active_property, element, options
                 )
-                if options['link'] and _is_subject_reference(element):
+                if isinstance(options['link'], dict) and options['link'] and _is_subject_reference(element):
                     # store linked element
                     options['link'].setdefault(element['@id'], []).append(
                         {'expanded': element, 'compacted': rval}
@@ -1556,7 +1557,11 @@ def _compact(self, active_ctx, active_property, element, options):
                     override_protected=True,
                 )
 
-            if options['link'] and '@id' in element:
+            if (
+                isinstance(options['link'], dict)
+                and options['link']
+                and '@id' in element
+            ):
                 # store linked element
                 options['link'].setdefault(element['@id'], []).append(
                     {'expanded': element, 'compacted': rval}

tests/test_jsonld.py

@@ -654,6 +654,66 @@ def test_compact_dates_with_datatype(self):
         framed = jsonld.frame(input, frame)
         assert framed == expected
 
+    def test_circular_references_link_and_embed(self):
+        input = {
+            "@context": "http://schema.org/",
+            "@type": "Person",
+            "name": "Jane Doe",
+            "jobTitle": "Professor",
+            "telephone": "(425) 123-4567",
+            "@id": "http://www.janedoe.com",
+            "knows": {
+                "name": "John Smith",
+                "@type": "Person",
+                "@id": "http://www.johnsmith.me",
+                "knows": {"@id": "http://www.janedoe.com"},
+            },
+        }
+
+        expected = {
+            "@context": "http://schema.org",
+            "@graph": [
+                {
+                "id": "http://www.janedoe.com",
+                "type": "Person",
+                "jobTitle": "Professor",
+                "knows": {
+                    "id": "http://www.johnsmith.me",
+                    "type": "Person",
+                    "knows": {
+                    "id": "http://www.janedoe.com"
+                    },
+                    "name": "John Smith"
+                },
+                "name": "Jane Doe",
+                "telephone": "(425) 123-4567"
+                },
+                {
+                "id": "http://www.johnsmith.me",
+                "type": "Person",
+                "knows": {
+                    "id": "http://www.janedoe.com",
+                    "type": "Person",
+                    "jobTitle": "Professor",
+                    "knows": {
+                    "id": "http://www.johnsmith.me"
+                    },
+                    "name": "Jane Doe",
+                    "telephone": "(425) 123-4567"
+                },
+                "name": "John Smith"
+                }
+            ]
+        }
+
+        frame = {'@context': 'http://schema.org', '@embed': '@once'}
+        assert expected == jsonld.frame(input, frame)
+
+        # this should result in a RuntimeError for exceeding recursion depth
+        frame = {'@context': 'http://schema.org', '@embed': '@link'}
+        with pytest.raises(RecursionError):
+            jsonld.frame(input, frame)
+
 
 class TestToRdf:
     # PR: https://github.com/digitalbazaar/pyld/pull/202