Copy @direction when cloning the active context; guard the @direction null reset

CHANGELOG.md

@@ -23,6 +23,8 @@
 ### Fixed
 
 - Preserved RDF literal lexical forms when converting through RDFLib, including canonical double output, large numeric values, and compound literal handling.
+- Fixed the active context clone dropping the default base direction: `@direction` now survives context layers like `@language`. Fixes [issue #337](https://github.com/digitalbazaar/pyld/issues/337).
+- Fixed `KeyError` when a context sets `@direction: null` and no default base direction is in effect.
 - Fixed `iri_resolver.unresolve()` query/fragment reconstruction while cleaning up the resolver docstring.
 - Invalid IRI base values within lists are now skipped when serializing to RDF. Fixes [toRdf#tli12](https://w3c.github.io/json-ld-api/tests/toRdf-manifest#tli12) and [toRdf#tli14](https://w3c.github.io/json-ld-api/tests/toRdf-manifest#tli14).
 - Literals with invalid `@language` no longer output triples. Fixes [toRdf#twf05](https://w3c.github.io/json-ld-api/tests/toRdf-manifest#twf05).

lib/pyld/jsonld.py

@@ -3536,7 +3536,8 @@ def _process_context(
                         code='invalid context entry',
                     )
                 if value is None:
-                    del rval['@direction']
+                    # mirror JS `delete`: a no-op when no direction is set
+                    rval.pop('@direction', None)
                 elif value != 'ltr' and value != 'rtl':
                     raise JsonLdError(
                         'Invalid JSON-LD syntax; @direction value must be null, "ltr", or "rtl".',
@@ -6310,6 +6311,8 @@ def _clone_active_context(self, active_ctx):
             child['previousContext'] = active_ctx['previousContext']
         if '@language' in active_ctx:
             child['@language'] = active_ctx['@language']
+        if '@direction' in active_ctx:
+            child['@direction'] = active_ctx['@direction']
         if '@vocab' in active_ctx:
             child['@vocab'] = active_ctx['@vocab']
         return child

tests/jsonld/test_expand.py

@@ -568,3 +568,109 @@ def test_blank_node_prefixes():
     expanded = jsonld.expand(input)
 
     assert expanded == expected
+
+
+# Issue 337
+def test_default_direction_survives_context_layers():
+    """
+    The default @direction should be kept across context layers, like the
+    default @language.
+    """
+    input = {
+        "@context": [
+            {"@language": "en", "@direction": "rtl"},
+            {"dummy": "http://example.com/dummy"},
+        ],
+        "http://example.com/p": "v",
+    }
+
+    expected = [
+        {
+            "http://example.com/p": [
+                {"@language": "en", "@direction": "rtl", "@value": "v"}
+            ],
+        }
+    ]
+
+    expanded = jsonld.expand(input)
+
+    assert expanded == expected
+
+# Issue 337
+def test_default_direction_inherited_into_scoped_context():
+    """
+    A property-scoped context should inherit the default @direction.
+    """
+    input = {
+        "@context": {
+            "@language": "en",
+            "@direction": "rtl",
+            "thing": {
+                "@id": "http://example.com/thing",
+                "@context": {"other": "http://example.com/other"},
+            },
+        },
+        "thing": {"http://example.com/label": "hello"},
+    }
+
+    expected = [
+        {
+            "http://example.com/thing": [
+                {
+                    "http://example.com/label": [
+                        {
+                            "@language": "en",
+                            "@direction": "rtl",
+                            "@value": "hello",
+                        }
+                    ],
+                }
+            ],
+        }
+    ]
+
+    expanded = jsonld.expand(input)
+
+    assert expanded == expected
+
+# Issue 337
+def test_scoped_context_can_override_or_clear_default_direction():
+    """
+    A scoped @direction entry should still override or clear the default.
+    """
+    input = {
+        "@context": {
+            "@direction": "rtl",
+            "ltr": {
+                "@id": "http://example.com/ltr",
+                "@context": {"@direction": "ltr"},
+            },
+            "none": {
+                "@id": "http://example.com/none",
+                "@context": {"@direction": None},
+            },
+        },
+        "ltr": {"http://example.com/label": "a"},
+        "none": {"http://example.com/label": "b"},
+    }
+
+    expected = [
+        {
+            "http://example.com/ltr": [
+                {
+                    "http://example.com/label": [
+                        {"@direction": "ltr", "@value": "a"}
+                    ],
+                }
+            ],
+            "http://example.com/none": [
+                {
+                    "http://example.com/label": [{"@value": "b"}],
+                }
+            ],
+        }
+    ]
+
+    expanded = jsonld.expand(input)
+
+    assert expanded == expected