Fix/root refs

CHANGELOG.md

@@ -14,6 +14,9 @@ Types of changes are:
 
 ## [Unreleased]
 
+* Added support for references which point to within the object containing the
+  `$ref` key.
+
 ## [0.7.1] - 2021-09-10
 
 ### Fixed

json_ref_dict/ref_pointer.py

@@ -47,10 +47,47 @@ def resolve_remote_with_uri(
         :return: tuple indicating (1) if doc was a ref (the ref URI returned)
             and (2) what that ref value was.
         """
-        if not (
-            isinstance(doc, abc.Mapping) and isinstance(doc.get("$ref"), str)
-        ):
+
+        is_ref = isinstance(doc, abc.Mapping) and isinstance(
+            doc.get("$ref"), str
+        )
+
+        if not is_ref:
             return None, None
+
+        ref = doc["$ref"]
+
+        is_local = ref.startswith("#")
+
+        if is_local:
+            # If this reference is local to this document, check the following
+            # to determine if this reference is actually pointing to within
+            # an object containing a `$ref` which is currently being resolved:
+            #
+            # 1) If we are already resolving this reference (i.e, `self` is the
+            #    same as the reference we just found)
+            # 2) This reference doesn't just point to itself (i.e, there are
+            #    more parts to resolve)
+            #
+            # If both these things are true, ignore this `$ref`, and allow the
+            # existing resolve process (represented by `self`) to continue.
+
+            # If a URI ended in `/`, there will be an empty item on the end of
+            # `parts`. For our purposes, this is the same as if it were not
+            # present. Modify the ephemeral `ref_pointer` `parts` to resolve
+            # this discrepancy
+            ref_pointer = RefPointer(ref)
+            if self.parts[-1] == "" and ref_pointer.parts[-1] != "":
+                ref_pointer.parts.append("")
+
+            is_same = self.parts == ref_pointer.parts
+            has_more = parts_idx + 1 < len(self.parts)
+
+            if is_same and has_more:
+                # `$ref` points to within the JSON object represented by `self`.
+                # Ignore.
+                return None, None
+
         remote_uri = self.uri.relative(doc["$ref"]).get(
             *[parse_segment(part) for part in self.parts[parts_idx + 1 :]]
         )
@@ -113,6 +150,7 @@ def resolve_with_uri(
                 if default is _nothing:
                     raise
                 return self.uri, default
+
         return self.uri, doc
 
     def set(self, doc: Any, value: Any, inplace: bool = True) -> NoReturn:

tests/schemas/conflicting-keys.yaml

@@ -0,0 +1,5 @@
+conflicting:
+  $ref: "#/real"
+  value: "bad"
+real:
+  value: "good"

tests/schemas/root-ref.json

@@ -0,0 +1 @@
+{"$ref": "#/definitions/bar", "definitions": {"bar": {"type": "integer"}}}

tests/test_loader.py

@@ -163,3 +163,13 @@ def test_immediate_references_is_detected():
 def test_immediate_references_can_be_bypassed():
     value = RefDict.from_uri("tests/schemas/immediate-ref.json#/type")
     assert value == "integer"
+
+
+def test_local_root_ref():
+    value = RefDict.from_uri("tests/schemas/root-ref.json#/")
+    assert value == {"type": "integer"}
+
+
+def test_local_conflicting_keys():
+    value = RefDict.from_uri("tests/schemas/conflicting-keys.yaml#/conflicting/value")
+    assert value == "good"