From 9ae3921842faa40aeedf9c1e4047c61aabdf969f Mon Sep 17 00:00:00 2001
From: Juan Cruz Viotti <jv@jviotti.com>
Date: Fri, 30 Jan 2026 16:55:44 -0400
Subject: [PATCH 1/4] [WIP] Optimise wrapping to subschemas with no references

See: https://github.com/sourcemeta/jsonschema/issues/629
Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>
---
 .../include/sourcemeta/core/jsonschema.h      |  15 +-
 src/core/jsonschema/jsonschema.cc             |  40 +-
 test/jsonschema/jsonschema_wrap_test.cc       | 421 ++++++------------
 3 files changed, 171 insertions(+), 305 deletions(-)

diff --git a/src/core/jsonschema/include/sourcemeta/core/jsonschema.h b/src/core/jsonschema/include/sourcemeta/core/jsonschema.h
index a18eeadab..c27287f39 100644
--- a/src/core/jsonschema/include/sourcemeta/core/jsonschema.h
+++ b/src/core/jsonschema/include/sourcemeta/core/jsonschema.h
@@ -422,16 +422,25 @@ auto wrap(std::string_view identifier) -> JSON;
 ///   "items": { "type": "string" }
 /// })JSON");
 ///
+/// sourcemeta::core::SchemaFrame frame{
+///     sourcemeta::core::SchemaFrame::Mode::References};
+/// frame.analyse(document, sourcemeta::core::schema_walker,
+///               sourcemeta::core::schema_resolver);
+///
+/// const auto location{frame.traverse(
+///     sourcemeta::core::Pointer{"items"},
+///     sourcemeta::core::SchemaFrame::LocationType::Subschema)};
+///
 /// const sourcemeta::core::JSON result =
-///   sourcemeta::core::wrap(document, { "items" },
+///   sourcemeta::core::wrap(document, frame, location.value().get(),
 ///     sourcemeta::core::schema_resolver);
 ///
 /// sourcemeta::core::prettify(result, std::cerr);
 /// std::cerr << "\n";
 /// ```
 SOURCEMETA_CORE_JSONSCHEMA_EXPORT
-auto wrap(const JSON &schema, const Pointer &pointer,
-          const SchemaResolver &resolver, std::string_view default_dialect = "")
+auto wrap(const JSON &schema, const SchemaFrame &frame,
+          const SchemaFrame::Location &location, const SchemaResolver &resolver)
     -> JSON;
 
 /// @ingroup jsonschema
diff --git a/src/core/jsonschema/jsonschema.cc b/src/core/jsonschema/jsonschema.cc
index aad330940..5a688328e 100644
--- a/src/core/jsonschema/jsonschema.cc
+++ b/src/core/jsonschema/jsonschema.cc
@@ -590,24 +590,34 @@ auto sourcemeta::core::wrap(const std::string_view identifier)
   return result;
 }
 
-auto sourcemeta::core::wrap(const sourcemeta::core::JSON &schema,
-                            const sourcemeta::core::Pointer &pointer,
-                            const sourcemeta::core::SchemaResolver &resolver,
-                            std::string_view default_dialect)
+auto sourcemeta::core::wrap(
+    const sourcemeta::core::JSON &schema,
+    const sourcemeta::core::SchemaFrame &frame,
+    const sourcemeta::core::SchemaFrame::Location &location,
+    const sourcemeta::core::SchemaResolver &resolver)
     -> sourcemeta::core::JSON {
+  assert(location.type != SchemaFrame::LocationType::Pointer);
+  const auto &pointer{location.pointer};
   assert(try_get(schema, pointer));
   if (pointer.empty()) {
     return schema;
   }
 
-  auto copy = schema;
-  const auto effective_dialect{dialect(copy, default_dialect)};
-  if (!effective_dialect.empty()) {
-    copy.assign("$schema", JSON{effective_dialect});
-  } else {
-    throw SchemaUnknownBaseDialectError();
+  const auto has_internal_references{
+      std::any_of(frame.references().cbegin(), frame.references().cend(),
+                  [&pointer](const auto &reference) {
+                    return reference.first.second.starts_with(pointer);
+                  })};
+
+  if (!has_internal_references) {
+    auto subschema{get(schema, pointer)};
+    subschema.assign("$schema", JSON{JSON::String{location.dialect}});
+    return subschema;
   }
 
+  auto copy = schema;
+  copy.assign("$schema", JSON{JSON::String{location.dialect}});
+
   auto result{JSON::make_object()};
   // JSON Schema 2020-12 is the first dialect that truly supports
   // cross-dialect references In practice, others do, but we can
@@ -622,13 +632,13 @@ auto sourcemeta::core::wrap(const sourcemeta::core::JSON &schema,
   // other schemas whose top-level identifiers are relative URIs don't
   // get affected. Otherwise, we would cause unintended base resolution.
   constexpr std::string_view WRAPPER_IDENTIFIER{"__sourcemeta-core-wrap__"};
-  const auto maybe_id{identify(copy, resolver, default_dialect)};
+  const auto maybe_id{identify(copy, resolver, location.dialect)};
   const auto id{maybe_id.empty() ? WRAPPER_IDENTIFIER : maybe_id};
 
   URI uri{id};
 
   try {
-    reidentify(copy, id, resolver, default_dialect);
+    reidentify(copy, id, resolver, location.dialect);
 
     // Otherwise we will get an error with the `WRAPPER_IDENTIFIER`, which will
     // be confusing to end users
@@ -647,9 +657,13 @@ auto sourcemeta::core::wrap(const sourcemeta::core::JSON &schema,
     uri.fragment(to_string(pointer));
     result.assign_assume_new("$ref", JSON{uri.recompose()});
   } else {
+    static const JSON::String DEFS{"$defs"};
+    static const JSON::String SCHEMA{"schema"};
     result.assign_assume_new(
         "$ref",
-        JSON{to_uri(Pointer{"$defs", "schema"}.concat(pointer)).recompose()});
+        JSON{to_uri(WeakPointer{std::cref(DEFS), std::cref(SCHEMA)}.concat(
+                        pointer))
+                 .recompose()});
   }
 
   return result;
diff --git a/test/jsonschema/jsonschema_wrap_test.cc b/test/jsonschema/jsonschema_wrap_test.cc
index a9b5fdbcc..35bc2afac 100644
--- a/test/jsonschema/jsonschema_wrap_test.cc
+++ b/test/jsonschema/jsonschema_wrap_test.cc
@@ -3,6 +3,21 @@
 #include <sourcemeta/core/json.h>
 #include <sourcemeta/core/jsonschema.h>
 
+static auto wrap_schema(const sourcemeta::core::JSON &schema,
+                        const sourcemeta::core::Pointer &pointer,
+                        std::string_view default_dialect = "")
+    -> sourcemeta::core::JSON {
+  sourcemeta::core::SchemaFrame frame{
+      sourcemeta::core::SchemaFrame::Mode::References};
+  frame.analyse(schema, sourcemeta::core::schema_walker,
+                sourcemeta::core::schema_resolver, default_dialect);
+  const auto location{
+      frame.traverse(sourcemeta::core::to_weak_pointer(pointer))};
+  assert(location.has_value());
+  return sourcemeta::core::wrap(schema, frame, location.value().get(),
+                                sourcemeta::core::schema_resolver);
+}
+
 TEST(JSONSchema_wrap, identifier_without_fragment) {
   const auto identifier{"https://www.example.com"};
   const auto result{sourcemeta::core::wrap(identifier)};
@@ -49,21 +64,11 @@ TEST(JSONSchema_wrap, schema_without_identifier) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(schema, {"items"},
-                                           sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {"items"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "__sourcemeta-core-wrap__#/items",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2020-12/schema",
-        "$id": "__sourcemeta-core-wrap__",
-        "items": {
-          "type": "string"
-        }
-      }
-    }
+    "type": "string"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -77,8 +82,7 @@ TEST(JSONSchema_wrap, schema_without_identifier_and_relative_uri) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(schema, {"items"},
-                                           sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {"items"})};
 
   // We don't want the relative reference to be resolved against
   // an absolute base
@@ -106,22 +110,12 @@ TEST(JSONSchema_wrap, schema_without_identifier_with_default_dialect) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(
-      schema, {"items"}, sourcemeta::core::schema_resolver,
-      "https://json-schema.org/draft/2020-12/schema")};
+  const auto result{wrap_schema(
+      schema, {"items"}, "https://json-schema.org/draft/2020-12/schema")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "__sourcemeta-core-wrap__#/items",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2020-12/schema",
-        "$id": "__sourcemeta-core-wrap__",
-        "items": {
-          "type": "string"
-        }
-      }
-    }
+    "type": "string"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -136,22 +130,12 @@ TEST(JSONSchema_wrap,
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(
-      schema, {"items"}, sourcemeta::core::schema_resolver,
-      "https://json-schema.org/draft/2019-09/schema")};
+  const auto result{wrap_schema(
+      schema, {"items"}, "https://json-schema.org/draft/2019-09/schema")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "__sourcemeta-core-wrap__#/items",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2020-12/schema",
-        "$id": "__sourcemeta-core-wrap__",
-        "items": {
-          "type": "string"
-        }
-      }
-    }
+    "type": "string"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -165,8 +149,7 @@ TEST(JSONSchema_wrap, schema_without_identifier_empty_pointer) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -185,8 +168,7 @@ TEST(JSONSchema_wrap, schema_without_identifier_without_dialect) {
     }
   })JSON")};
 
-  EXPECT_THROW(sourcemeta::core::wrap(schema, {"items"},
-                                      sourcemeta::core::schema_resolver),
+  EXPECT_THROW(wrap_schema(schema, {"items"}),
                sourcemeta::core::SchemaUnknownBaseDialectError);
 }
 
@@ -199,21 +181,11 @@ TEST(JSONSchema_wrap, schema_with_identifier) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(schema, {"items"},
-                                           sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {"items"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "https://sourcemeta.com/1#/items",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2020-12/schema",
-        "$id": "https://sourcemeta.com/1",
-        "items": {
-          "type": "string"
-        }
-      }
-    }
+    "type": "string"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -228,21 +200,11 @@ TEST(JSONSchema_wrap, schema_with_identifier_trailing_empty_fragment) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(schema, {"items"},
-                                           sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {"items"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "https://sourcemeta.com/1#/items",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2020-12/schema",
-        "$id": "https://sourcemeta.com/1#",
-        "items": {
-          "type": "string"
-        }
-      }
-    }
+    "type": "string"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -257,22 +219,12 @@ TEST(JSONSchema_wrap, schema_with_identifier_different_default_dialect) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(
-      schema, {"items"}, sourcemeta::core::schema_resolver,
-      "https://json-schema.org/draft/2019-09/schema")};
+  const auto result{wrap_schema(
+      schema, {"items"}, "https://json-schema.org/draft/2019-09/schema")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "https://sourcemeta.com/1#/items",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2020-12/schema",
-        "$id": "https://sourcemeta.com/1",
-        "items": {
-          "type": "string"
-        }
-      }
-    }
+    "type": "string"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -286,22 +238,12 @@ TEST(JSONSchema_wrap, schema_with_identifier_default_dialect) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(
-      schema, {"items"}, sourcemeta::core::schema_resolver,
-      "https://json-schema.org/draft/2019-09/schema")};
+  const auto result{wrap_schema(
+      schema, {"items"}, "https://json-schema.org/draft/2019-09/schema")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "https://sourcemeta.com/1#/items",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2019-09/schema",
-        "$id": "https://sourcemeta.com/1",
-        "items": {
-          "type": "string"
-        }
-      }
-    }
+    "$schema": "https://json-schema.org/draft/2019-09/schema",
+    "type": "string"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -309,16 +251,17 @@ TEST(JSONSchema_wrap, schema_with_identifier_default_dialect) {
 
 TEST(JSONSchema_wrap, schema_with_identifier_empty_pointer) {
   const auto schema{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
     "$id": "https://sourcemeta.com/1",
     "items": {
       "type": "string"
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
     "$id": "https://sourcemeta.com/1",
     "items": {
       "type": "string"
@@ -336,48 +279,17 @@ TEST(JSONSchema_wrap, schema_with_identifier_no_dialect) {
     }
   })JSON")};
 
-  EXPECT_THROW(sourcemeta::core::wrap(schema, {"items"},
-                                      sourcemeta::core::schema_resolver),
+  EXPECT_THROW(wrap_schema(schema, {"items"}),
                sourcemeta::core::SchemaUnknownBaseDialectError);
 }
 
-TEST(JSONSchema_wrap, schema_with_identifier_with_fragment) {
-  const auto schema{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "http://json-schema.org/draft-04/schema#",
-    "id": "https://sourcemeta.com/1#foo",
-    "items": {
-      "type": "string"
-    }
-  })JSON")};
-
-  const auto result{sourcemeta::core::wrap(schema, {"items"},
-                                           sourcemeta::core::schema_resolver)};
-
-  const auto expected{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "#/$defs/schema/items",
-    "$defs": {
-      "schema": {
-        "$schema": "http://json-schema.org/draft-04/schema#",
-        "id": "https://sourcemeta.com/1#foo",
-        "items": {
-          "type": "string"
-        }
-      }
-    }
-  })JSON")};
-
-  EXPECT_EQ(result, expected);
-}
-
 TEST(JSONSchema_wrap, draft4_standalone_ref_with_default_dialect) {
   const auto schema{sourcemeta::core::parse_json(R"JSON({
     "$ref": "https://example.com"
   })JSON")};
 
   const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver,
-                             "http://json-schema.org/draft-04/schema#")};
+      wrap_schema(schema, {}, "http://json-schema.org/draft-04/schema#")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$ref": "https://example.com"
@@ -396,8 +308,7 @@ TEST(JSONSchema_wrap, draft4_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-04/schema#",
@@ -411,21 +322,6 @@ TEST(JSONSchema_wrap, draft4_top_level_ref_with_id_empty) {
   EXPECT_EQ(result, expected);
 }
 
-TEST(JSONSchema_wrap, draft4_top_level_ref_with_id_definitions_foo) {
-  const auto schema{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "http://json-schema.org/draft-04/schema#",
-    "id": "https://example.com",
-    "$ref": "#/definitions/foo",
-    "definitions": {
-      "foo": {}
-    }
-  })JSON")};
-
-  EXPECT_THROW(sourcemeta::core::wrap(schema, {"definitions", "foo"},
-                                      sourcemeta::core::schema_resolver),
-               sourcemeta::core::SchemaError);
-}
-
 TEST(JSONSchema_wrap, draft4_top_level_ref_without_id_empty) {
   const auto schema{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-04/schema#",
@@ -435,8 +331,7 @@ TEST(JSONSchema_wrap, draft4_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-04/schema#",
@@ -449,28 +344,13 @@ TEST(JSONSchema_wrap, draft4_top_level_ref_without_id_empty) {
   EXPECT_EQ(result, expected);
 }
 
-TEST(JSONSchema_wrap, draft4_top_level_ref_without_id_definitions_foo) {
-  const auto schema{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "http://json-schema.org/draft-04/schema#",
-    "$ref": "#/definitions/foo",
-    "definitions": {
-      "foo": {}
-    }
-  })JSON")};
-
-  EXPECT_THROW(sourcemeta::core::wrap(schema, {"definitions", "foo"},
-                                      sourcemeta::core::schema_resolver),
-               sourcemeta::core::SchemaError);
-}
-
 TEST(JSONSchema_wrap, draft6_standalone_ref_with_default_dialect) {
   const auto schema{sourcemeta::core::parse_json(R"JSON({
     "$ref": "https://example.com"
   })JSON")};
 
   const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver,
-                             "http://json-schema.org/draft-06/schema#")};
+      wrap_schema(schema, {}, "http://json-schema.org/draft-06/schema#")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$ref": "https://example.com"
@@ -489,8 +369,7 @@ TEST(JSONSchema_wrap, draft6_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-06/schema#",
@@ -504,21 +383,6 @@ TEST(JSONSchema_wrap, draft6_top_level_ref_with_id_empty) {
   EXPECT_EQ(result, expected);
 }
 
-TEST(JSONSchema_wrap, draft6_top_level_ref_with_id_definitions_foo) {
-  const auto schema{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "http://json-schema.org/draft-06/schema#",
-    "$id": "https://example.com",
-    "$ref": "#/definitions/foo",
-    "definitions": {
-      "foo": {}
-    }
-  })JSON")};
-
-  EXPECT_THROW(sourcemeta::core::wrap(schema, {"definitions", "foo"},
-                                      sourcemeta::core::schema_resolver),
-               sourcemeta::core::SchemaError);
-}
-
 TEST(JSONSchema_wrap, draft6_top_level_ref_without_id_empty) {
   const auto schema{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-06/schema#",
@@ -528,8 +392,7 @@ TEST(JSONSchema_wrap, draft6_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-06/schema#",
@@ -542,28 +405,13 @@ TEST(JSONSchema_wrap, draft6_top_level_ref_without_id_empty) {
   EXPECT_EQ(result, expected);
 }
 
-TEST(JSONSchema_wrap, draft6_top_level_ref_without_id_definitions_foo) {
-  const auto schema{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "http://json-schema.org/draft-06/schema#",
-    "$ref": "#/definitions/foo",
-    "definitions": {
-      "foo": {}
-    }
-  })JSON")};
-
-  EXPECT_THROW(sourcemeta::core::wrap(schema, {"definitions", "foo"},
-                                      sourcemeta::core::schema_resolver),
-               sourcemeta::core::SchemaError);
-}
-
 TEST(JSONSchema_wrap, draft7_standalone_ref_with_default_dialect) {
   const auto schema{sourcemeta::core::parse_json(R"JSON({
     "$ref": "https://example.com"
   })JSON")};
 
   const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver,
-                             "http://json-schema.org/draft-07/schema#")};
+      wrap_schema(schema, {}, "http://json-schema.org/draft-07/schema#")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$ref": "https://example.com"
@@ -582,8 +430,7 @@ TEST(JSONSchema_wrap, draft7_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-07/schema#",
@@ -597,21 +444,6 @@ TEST(JSONSchema_wrap, draft7_top_level_ref_with_id_empty) {
   EXPECT_EQ(result, expected);
 }
 
-TEST(JSONSchema_wrap, draft7_top_level_ref_with_id_definitions_foo) {
-  const auto schema{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "http://json-schema.org/draft-07/schema#",
-    "$id": "https://example.com",
-    "$ref": "#/definitions/foo",
-    "definitions": {
-      "foo": {}
-    }
-  })JSON")};
-
-  EXPECT_THROW(sourcemeta::core::wrap(schema, {"definitions", "foo"},
-                                      sourcemeta::core::schema_resolver),
-               sourcemeta::core::SchemaError);
-}
-
 TEST(JSONSchema_wrap, draft7_top_level_ref_without_id_empty) {
   const auto schema{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-07/schema#",
@@ -621,8 +453,7 @@ TEST(JSONSchema_wrap, draft7_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-07/schema#",
@@ -635,20 +466,6 @@ TEST(JSONSchema_wrap, draft7_top_level_ref_without_id_empty) {
   EXPECT_EQ(result, expected);
 }
 
-TEST(JSONSchema_wrap, draft7_top_level_ref_without_id_definitions_foo) {
-  const auto schema{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "http://json-schema.org/draft-07/schema#",
-    "$ref": "#/definitions/foo",
-    "definitions": {
-      "foo": {}
-    }
-  })JSON")};
-
-  EXPECT_THROW(sourcemeta::core::wrap(schema, {"definitions", "foo"},
-                                      sourcemeta::core::schema_resolver),
-               sourcemeta::core::SchemaError);
-}
-
 TEST(JSONSchema_wrap, 2019_09_top_level_ref_with_id_empty) {
   const auto schema{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -659,8 +476,7 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -684,22 +500,10 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_with_id_defs_foo) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(schema, {"$defs", "foo"},
-                                           sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {"$defs", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "https://example.com#/$defs/foo",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2019-09/schema",
-        "$id": "https://example.com",
-        "$ref": "#/$defs/foo",
-        "$defs": {
-          "foo": {}
-        }
-      }
-    }
+    "$schema": "https://json-schema.org/draft/2019-09/schema"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -714,8 +518,7 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -737,22 +540,10 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_without_id_defs_foo) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(schema, {"$defs", "foo"},
-                                           sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {"$defs", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "__sourcemeta-core-wrap__#/$defs/foo",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2019-09/schema",
-        "$id": "__sourcemeta-core-wrap__",
-        "$ref": "#/$defs/foo",
-        "$defs": {
-          "foo": {}
-        }
-      }
-    }
+    "$schema": "https://json-schema.org/draft/2019-09/schema"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -768,8 +559,7 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -793,22 +583,10 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_with_id_defs_foo) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(schema, {"$defs", "foo"},
-                                           sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {"$defs", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
-    "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "https://example.com#/$defs/foo",
-    "$defs": {
-      "schema": {
-        "$schema": "https://json-schema.org/draft/2020-12/schema",
-        "$id": "https://example.com",
-        "$ref": "#/$defs/foo",
-        "$defs": {
-          "foo": {}
-        }
-      }
-    }
+    "$schema": "https://json-schema.org/draft/2020-12/schema"
   })JSON")};
 
   EXPECT_EQ(result, expected);
@@ -823,8 +601,7 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{
-      sourcemeta::core::wrap(schema, {}, sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -846,19 +623,85 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_without_id_defs_foo) {
     }
   })JSON")};
 
-  const auto result{sourcemeta::core::wrap(schema, {"$defs", "foo"},
-                                           sourcemeta::core::schema_resolver)};
+  const auto result{wrap_schema(schema, {"$defs", "foo"})};
+
+  const auto expected{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema"
+  })JSON")};
+
+  EXPECT_EQ(result, expected);
+}
+
+TEST(JSONSchema_wrap, subschema_with_direct_ref) {
+  const auto schema{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "$id": "https://example.com",
+    "$defs": {
+      "string": { "type": "string" }
+    },
+    "properties": {
+      "foo": { "$ref": "#/$defs/string" }
+    }
+  })JSON")};
+
+  const auto result{wrap_schema(schema, {"properties", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
-    "$ref": "__sourcemeta-core-wrap__#/$defs/foo",
+    "$ref": "https://example.com#/properties/foo",
     "$defs": {
       "schema": {
         "$schema": "https://json-schema.org/draft/2020-12/schema",
-        "$id": "__sourcemeta-core-wrap__",
-        "$ref": "#/$defs/foo",
+        "$id": "https://example.com",
+        "$defs": {
+          "string": { "type": "string" }
+        },
+        "properties": {
+          "foo": { "$ref": "#/$defs/string" }
+        }
+      }
+    }
+  })JSON")};
+
+  EXPECT_EQ(result, expected);
+}
+
+TEST(JSONSchema_wrap, subschema_with_nested_ref) {
+  const auto schema{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "$id": "https://example.com",
+    "$defs": {
+      "string": { "type": "string" }
+    },
+    "properties": {
+      "foo": {
+        "type": "object",
+        "properties": {
+          "bar": { "$ref": "#/$defs/string" }
+        }
+      }
+    }
+  })JSON")};
+
+  const auto result{wrap_schema(schema, {"properties", "foo"})};
+
+  const auto expected{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "$ref": "https://example.com#/properties/foo",
+    "$defs": {
+      "schema": {
+        "$schema": "https://json-schema.org/draft/2020-12/schema",
+        "$id": "https://example.com",
         "$defs": {
-          "foo": {}
+          "string": { "type": "string" }
+        },
+        "properties": {
+          "foo": {
+            "type": "object",
+            "properties": {
+              "bar": { "$ref": "#/$defs/string" }
+            }
+          }
         }
       }
     }

From 235f820effac93df80e494c258342657d4cf3a42 Mon Sep 17 00:00:00 2001
From: Juan Cruz Viotti <jv@jviotti.com>
Date: Mon, 2 Feb 2026 09:14:19 -0400
Subject: [PATCH 2/4] Base

Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>
---
 .../include/sourcemeta/core/jsonschema.h      |   7 +-
 src/core/jsonschema/jsonschema.cc             |   6 +-
 test/jsonschema/jsonschema_wrap_test.cc       | 103 ++++++++++++------
 3 files changed, 79 insertions(+), 37 deletions(-)

diff --git a/src/core/jsonschema/include/sourcemeta/core/jsonschema.h b/src/core/jsonschema/include/sourcemeta/core/jsonschema.h
index c27287f39..2d21a8215 100644
--- a/src/core/jsonschema/include/sourcemeta/core/jsonschema.h
+++ b/src/core/jsonschema/include/sourcemeta/core/jsonschema.h
@@ -431,17 +431,18 @@ auto wrap(std::string_view identifier) -> JSON;
 ///     sourcemeta::core::Pointer{"items"},
 ///     sourcemeta::core::SchemaFrame::LocationType::Subschema)};
 ///
+/// sourcemeta::core::WeakPointer base;
 /// const sourcemeta::core::JSON result =
 ///   sourcemeta::core::wrap(document, frame, location.value().get(),
-///     sourcemeta::core::schema_resolver);
+///     sourcemeta::core::schema_resolver, base);
 ///
 /// sourcemeta::core::prettify(result, std::cerr);
 /// std::cerr << "\n";
 /// ```
 SOURCEMETA_CORE_JSONSCHEMA_EXPORT
 auto wrap(const JSON &schema, const SchemaFrame &frame,
-          const SchemaFrame::Location &location, const SchemaResolver &resolver)
-    -> JSON;
+          const SchemaFrame::Location &location, const SchemaResolver &resolver,
+          WeakPointer &base) -> JSON;
 
 /// @ingroup jsonschema
 ///
diff --git a/src/core/jsonschema/jsonschema.cc b/src/core/jsonschema/jsonschema.cc
index 5a688328e..45776d7c1 100644
--- a/src/core/jsonschema/jsonschema.cc
+++ b/src/core/jsonschema/jsonschema.cc
@@ -594,8 +594,8 @@ auto sourcemeta::core::wrap(
     const sourcemeta::core::JSON &schema,
     const sourcemeta::core::SchemaFrame &frame,
     const sourcemeta::core::SchemaFrame::Location &location,
-    const sourcemeta::core::SchemaResolver &resolver)
-    -> sourcemeta::core::JSON {
+    const sourcemeta::core::SchemaResolver &resolver,
+    sourcemeta::core::WeakPointer &base) -> sourcemeta::core::JSON {
   assert(location.type != SchemaFrame::LocationType::Pointer);
   const auto &pointer{location.pointer};
   assert(try_get(schema, pointer));
@@ -666,6 +666,8 @@ auto sourcemeta::core::wrap(
                  .recompose()});
   }
 
+  static const JSON::String REF{"$ref"};
+  base.push_back(REF);
   return result;
 }
 
diff --git a/test/jsonschema/jsonschema_wrap_test.cc b/test/jsonschema/jsonschema_wrap_test.cc
index 35bc2afac..1c680ec21 100644
--- a/test/jsonschema/jsonschema_wrap_test.cc
+++ b/test/jsonschema/jsonschema_wrap_test.cc
@@ -3,10 +3,12 @@
 #include <sourcemeta/core/json.h>
 #include <sourcemeta/core/jsonschema.h>
 
+#include <utility> // std::pair
+
 static auto wrap_schema(const sourcemeta::core::JSON &schema,
                         const sourcemeta::core::Pointer &pointer,
                         std::string_view default_dialect = "")
-    -> sourcemeta::core::JSON {
+    -> std::pair<sourcemeta::core::JSON, sourcemeta::core::Pointer> {
   sourcemeta::core::SchemaFrame frame{
       sourcemeta::core::SchemaFrame::Mode::References};
   frame.analyse(schema, sourcemeta::core::schema_walker,
@@ -14,8 +16,10 @@ static auto wrap_schema(const sourcemeta::core::JSON &schema,
   const auto location{
       frame.traverse(sourcemeta::core::to_weak_pointer(pointer))};
   assert(location.has_value());
-  return sourcemeta::core::wrap(schema, frame, location.value().get(),
-                                sourcemeta::core::schema_resolver);
+  sourcemeta::core::WeakPointer base;
+  auto result{sourcemeta::core::wrap(schema, frame, location.value().get(),
+                                     sourcemeta::core::schema_resolver, base)};
+  return {std::move(result), sourcemeta::core::to_pointer(base)};
 }
 
 TEST(JSONSchema_wrap, identifier_without_fragment) {
@@ -64,7 +68,7 @@ TEST(JSONSchema_wrap, schema_without_identifier) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"items"})};
+  const auto [result, base]{wrap_schema(schema, {"items"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -72,6 +76,7 @@ TEST(JSONSchema_wrap, schema_without_identifier) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, schema_without_identifier_and_relative_uri) {
@@ -82,7 +87,7 @@ TEST(JSONSchema_wrap, schema_without_identifier_and_relative_uri) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"items"})};
+  const auto [result, base]{wrap_schema(schema, {"items"})};
 
   // We don't want the relative reference to be resolved against
   // an absolute base
@@ -101,6 +106,9 @@ TEST(JSONSchema_wrap, schema_without_identifier_and_relative_uri) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_EQ(base.size(), 1);
+  EXPECT_TRUE(base.at(0).is_property());
+  EXPECT_EQ(base.at(0).to_property(), "$ref");
 }
 
 TEST(JSONSchema_wrap, schema_without_identifier_with_default_dialect) {
@@ -110,7 +118,7 @@ TEST(JSONSchema_wrap, schema_without_identifier_with_default_dialect) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(
+  const auto [result, base]{wrap_schema(
       schema, {"items"}, "https://json-schema.org/draft/2020-12/schema")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
@@ -119,6 +127,7 @@ TEST(JSONSchema_wrap, schema_without_identifier_with_default_dialect) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap,
@@ -130,7 +139,7 @@ TEST(JSONSchema_wrap,
     }
   })JSON")};
 
-  const auto result{wrap_schema(
+  const auto [result, base]{wrap_schema(
       schema, {"items"}, "https://json-schema.org/draft/2019-09/schema")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
@@ -139,6 +148,7 @@ TEST(JSONSchema_wrap,
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, schema_without_identifier_empty_pointer) {
@@ -149,7 +159,7 @@ TEST(JSONSchema_wrap, schema_without_identifier_empty_pointer) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -159,6 +169,7 @@ TEST(JSONSchema_wrap, schema_without_identifier_empty_pointer) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, schema_without_identifier_without_dialect) {
@@ -181,7 +192,7 @@ TEST(JSONSchema_wrap, schema_with_identifier) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"items"})};
+  const auto [result, base]{wrap_schema(schema, {"items"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -189,6 +200,7 @@ TEST(JSONSchema_wrap, schema_with_identifier) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, schema_with_identifier_trailing_empty_fragment) {
@@ -200,7 +212,7 @@ TEST(JSONSchema_wrap, schema_with_identifier_trailing_empty_fragment) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"items"})};
+  const auto [result, base]{wrap_schema(schema, {"items"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -208,6 +220,7 @@ TEST(JSONSchema_wrap, schema_with_identifier_trailing_empty_fragment) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, schema_with_identifier_different_default_dialect) {
@@ -219,7 +232,7 @@ TEST(JSONSchema_wrap, schema_with_identifier_different_default_dialect) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(
+  const auto [result, base]{wrap_schema(
       schema, {"items"}, "https://json-schema.org/draft/2019-09/schema")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
@@ -228,6 +241,7 @@ TEST(JSONSchema_wrap, schema_with_identifier_different_default_dialect) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, schema_with_identifier_default_dialect) {
@@ -238,7 +252,7 @@ TEST(JSONSchema_wrap, schema_with_identifier_default_dialect) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(
+  const auto [result, base]{wrap_schema(
       schema, {"items"}, "https://json-schema.org/draft/2019-09/schema")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
@@ -247,6 +261,7 @@ TEST(JSONSchema_wrap, schema_with_identifier_default_dialect) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, schema_with_identifier_empty_pointer) {
@@ -258,7 +273,7 @@ TEST(JSONSchema_wrap, schema_with_identifier_empty_pointer) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -269,6 +284,7 @@ TEST(JSONSchema_wrap, schema_with_identifier_empty_pointer) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, schema_with_identifier_no_dialect) {
@@ -288,7 +304,7 @@ TEST(JSONSchema_wrap, draft4_standalone_ref_with_default_dialect) {
     "$ref": "https://example.com"
   })JSON")};
 
-  const auto result{
+  const auto [result, base]{
       wrap_schema(schema, {}, "http://json-schema.org/draft-04/schema#")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
@@ -296,6 +312,7 @@ TEST(JSONSchema_wrap, draft4_standalone_ref_with_default_dialect) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, draft4_top_level_ref_with_id_empty) {
@@ -308,7 +325,7 @@ TEST(JSONSchema_wrap, draft4_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-04/schema#",
@@ -320,6 +337,7 @@ TEST(JSONSchema_wrap, draft4_top_level_ref_with_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, draft4_top_level_ref_without_id_empty) {
@@ -331,7 +349,7 @@ TEST(JSONSchema_wrap, draft4_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-04/schema#",
@@ -342,6 +360,7 @@ TEST(JSONSchema_wrap, draft4_top_level_ref_without_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, draft6_standalone_ref_with_default_dialect) {
@@ -349,7 +368,7 @@ TEST(JSONSchema_wrap, draft6_standalone_ref_with_default_dialect) {
     "$ref": "https://example.com"
   })JSON")};
 
-  const auto result{
+  const auto [result, base]{
       wrap_schema(schema, {}, "http://json-schema.org/draft-06/schema#")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
@@ -357,6 +376,7 @@ TEST(JSONSchema_wrap, draft6_standalone_ref_with_default_dialect) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, draft6_top_level_ref_with_id_empty) {
@@ -369,7 +389,7 @@ TEST(JSONSchema_wrap, draft6_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-06/schema#",
@@ -381,6 +401,7 @@ TEST(JSONSchema_wrap, draft6_top_level_ref_with_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, draft6_top_level_ref_without_id_empty) {
@@ -392,7 +413,7 @@ TEST(JSONSchema_wrap, draft6_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-06/schema#",
@@ -403,6 +424,7 @@ TEST(JSONSchema_wrap, draft6_top_level_ref_without_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, draft7_standalone_ref_with_default_dialect) {
@@ -410,7 +432,7 @@ TEST(JSONSchema_wrap, draft7_standalone_ref_with_default_dialect) {
     "$ref": "https://example.com"
   })JSON")};
 
-  const auto result{
+  const auto [result, base]{
       wrap_schema(schema, {}, "http://json-schema.org/draft-07/schema#")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
@@ -418,6 +440,7 @@ TEST(JSONSchema_wrap, draft7_standalone_ref_with_default_dialect) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, draft7_top_level_ref_with_id_empty) {
@@ -430,7 +453,7 @@ TEST(JSONSchema_wrap, draft7_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-07/schema#",
@@ -442,6 +465,7 @@ TEST(JSONSchema_wrap, draft7_top_level_ref_with_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, draft7_top_level_ref_without_id_empty) {
@@ -453,7 +477,7 @@ TEST(JSONSchema_wrap, draft7_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "http://json-schema.org/draft-07/schema#",
@@ -464,6 +488,7 @@ TEST(JSONSchema_wrap, draft7_top_level_ref_without_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, 2019_09_top_level_ref_with_id_empty) {
@@ -476,7 +501,7 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -488,6 +513,7 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_with_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, 2019_09_top_level_ref_with_id_defs_foo) {
@@ -500,13 +526,14 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_with_id_defs_foo) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"$defs", "foo"})};
+  const auto [result, base]{wrap_schema(schema, {"$defs", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2019-09/schema"
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, 2019_09_top_level_ref_without_id_empty) {
@@ -518,7 +545,7 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -529,6 +556,7 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_without_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, 2019_09_top_level_ref_without_id_defs_foo) {
@@ -540,13 +568,14 @@ TEST(JSONSchema_wrap, 2019_09_top_level_ref_without_id_defs_foo) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"$defs", "foo"})};
+  const auto [result, base]{wrap_schema(schema, {"$defs", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2019-09/schema"
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, 2020_12_top_level_ref_with_id_empty) {
@@ -559,7 +588,7 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_with_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -571,6 +600,7 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_with_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, 2020_12_top_level_ref_with_id_defs_foo) {
@@ -583,13 +613,14 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_with_id_defs_foo) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"$defs", "foo"})};
+  const auto [result, base]{wrap_schema(schema, {"$defs", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema"
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, 2020_12_top_level_ref_without_id_empty) {
@@ -601,7 +632,7 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_without_id_empty) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {})};
+  const auto [result, base]{wrap_schema(schema, {})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -612,6 +643,7 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_without_id_empty) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, 2020_12_top_level_ref_without_id_defs_foo) {
@@ -623,13 +655,14 @@ TEST(JSONSchema_wrap, 2020_12_top_level_ref_without_id_defs_foo) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"$defs", "foo"})};
+  const auto [result, base]{wrap_schema(schema, {"$defs", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema"
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_TRUE(base.empty());
 }
 
 TEST(JSONSchema_wrap, subschema_with_direct_ref) {
@@ -644,7 +677,7 @@ TEST(JSONSchema_wrap, subschema_with_direct_ref) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"properties", "foo"})};
+  const auto [result, base]{wrap_schema(schema, {"properties", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -664,6 +697,9 @@ TEST(JSONSchema_wrap, subschema_with_direct_ref) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_EQ(base.size(), 1);
+  EXPECT_TRUE(base.at(0).is_property());
+  EXPECT_EQ(base.at(0).to_property(), "$ref");
 }
 
 TEST(JSONSchema_wrap, subschema_with_nested_ref) {
@@ -683,7 +719,7 @@ TEST(JSONSchema_wrap, subschema_with_nested_ref) {
     }
   })JSON")};
 
-  const auto result{wrap_schema(schema, {"properties", "foo"})};
+  const auto [result, base]{wrap_schema(schema, {"properties", "foo"})};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -708,4 +744,7 @@ TEST(JSONSchema_wrap, subschema_with_nested_ref) {
   })JSON")};
 
   EXPECT_EQ(result, expected);
+  EXPECT_EQ(base.size(), 1);
+  EXPECT_TRUE(base.at(0).is_property());
+  EXPECT_EQ(base.at(0).to_property(), "$ref");
 }

From cf72495629ff9d4c49f8efaed179526691915d04 Mon Sep 17 00:00:00 2001
From: Juan Cruz Viotti <jv@jviotti.com>
Date: Mon, 2 Feb 2026 09:24:39 -0400
Subject: [PATCH 3/4] Better

Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>
---
 src/core/jsonschema/jsonschema.cc       | 10 ++++++----
 test/jsonschema/jsonschema_wrap_test.cc |  3 +++
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/core/jsonschema/jsonschema.cc b/src/core/jsonschema/jsonschema.cc
index 45776d7c1..11b25bc31 100644
--- a/src/core/jsonschema/jsonschema.cc
+++ b/src/core/jsonschema/jsonschema.cc
@@ -598,11 +598,13 @@ auto sourcemeta::core::wrap(
     sourcemeta::core::WeakPointer &base) -> sourcemeta::core::JSON {
   assert(location.type != SchemaFrame::LocationType::Pointer);
   const auto &pointer{location.pointer};
-  assert(try_get(schema, pointer));
   if (pointer.empty()) {
-    return schema;
+    auto copy = schema;
+    copy.assign("$schema", JSON{location.dialect});
+    return copy;
   }
 
+  assert(try_get(schema, pointer));
   const auto has_internal_references{
       std::any_of(frame.references().cbegin(), frame.references().cend(),
                   [&pointer](const auto &reference) {
@@ -611,12 +613,12 @@ auto sourcemeta::core::wrap(
 
   if (!has_internal_references) {
     auto subschema{get(schema, pointer)};
-    subschema.assign("$schema", JSON{JSON::String{location.dialect}});
+    subschema.assign("$schema", JSON{location.dialect});
     return subschema;
   }
 
   auto copy = schema;
-  copy.assign("$schema", JSON{JSON::String{location.dialect}});
+  copy.assign("$schema", JSON{location.dialect});
 
   auto result{JSON::make_object()};
   // JSON Schema 2020-12 is the first dialect that truly supports
diff --git a/test/jsonschema/jsonschema_wrap_test.cc b/test/jsonschema/jsonschema_wrap_test.cc
index 1c680ec21..9832c461f 100644
--- a/test/jsonschema/jsonschema_wrap_test.cc
+++ b/test/jsonschema/jsonschema_wrap_test.cc
@@ -308,6 +308,7 @@ TEST(JSONSchema_wrap, draft4_standalone_ref_with_default_dialect) {
       wrap_schema(schema, {}, "http://json-schema.org/draft-04/schema#")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "http://json-schema.org/draft-04/schema#",
     "$ref": "https://example.com"
   })JSON")};
 
@@ -372,6 +373,7 @@ TEST(JSONSchema_wrap, draft6_standalone_ref_with_default_dialect) {
       wrap_schema(schema, {}, "http://json-schema.org/draft-06/schema#")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "http://json-schema.org/draft-06/schema#",
     "$ref": "https://example.com"
   })JSON")};
 
@@ -436,6 +438,7 @@ TEST(JSONSchema_wrap, draft7_standalone_ref_with_default_dialect) {
       wrap_schema(schema, {}, "http://json-schema.org/draft-07/schema#")};
 
   const auto expected{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "http://json-schema.org/draft-07/schema#",
     "$ref": "https://example.com"
   })JSON")};
 

From 139f978b289ac7200316269293e90d3271a8a44d Mon Sep 17 00:00:00 2001
From: Juan Cruz Viotti <jv@jviotti.com>
Date: Mon, 2 Feb 2026 09:32:59 -0400
Subject: [PATCH 4/4] Fixes

Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>
---
 src/core/jsonschema/include/sourcemeta/core/jsonschema.h | 2 +-
 src/core/jsonschema/jsonschema.cc                        | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/core/jsonschema/include/sourcemeta/core/jsonschema.h b/src/core/jsonschema/include/sourcemeta/core/jsonschema.h
index 2d21a8215..54005110b 100644
--- a/src/core/jsonschema/include/sourcemeta/core/jsonschema.h
+++ b/src/core/jsonschema/include/sourcemeta/core/jsonschema.h
@@ -428,7 +428,7 @@ auto wrap(std::string_view identifier) -> JSON;
 ///               sourcemeta::core::schema_resolver);
 ///
 /// const auto location{frame.traverse(
-///     sourcemeta::core::Pointer{"items"},
+///     sourcemeta::core::WeakPointer{"items"},
 ///     sourcemeta::core::SchemaFrame::LocationType::Subschema)};
 ///
 /// sourcemeta::core::WeakPointer base;
diff --git a/src/core/jsonschema/jsonschema.cc b/src/core/jsonschema/jsonschema.cc
index 11b25bc31..78814050b 100644
--- a/src/core/jsonschema/jsonschema.cc
+++ b/src/core/jsonschema/jsonschema.cc
@@ -596,11 +596,16 @@ auto sourcemeta::core::wrap(
     const sourcemeta::core::SchemaFrame::Location &location,
     const sourcemeta::core::SchemaResolver &resolver,
     sourcemeta::core::WeakPointer &base) -> sourcemeta::core::JSON {
+  assert(frame.mode() == SchemaFrame::Mode::References);
   assert(location.type != SchemaFrame::LocationType::Pointer);
+
   const auto &pointer{location.pointer};
   if (pointer.empty()) {
     auto copy = schema;
-    copy.assign("$schema", JSON{location.dialect});
+    if (copy.is_object()) {
+      copy.assign("$schema", JSON{location.dialect});
+    }
+
     return copy;
   }