Don't directly unroll $ref in exhaustive mode (#1282)

Signed-off-by: Juan Cruz Viotti <[email protected]>

src/jsonschema/default_compiler_draft4.h

@@ -84,12 +84,13 @@ auto compiler_draft4_core_ref(
 
   if (!is_recursive && direct_children_references <= 5) {
     // TODO: Enable this optimization for 2019-09 on-wards
-    if (schema_context.vocabularies.contains(
-            "http://json-schema.org/draft-04/schema#") ||
-        schema_context.vocabularies.contains(
-            "http://json-schema.org/draft-06/schema#") ||
-        schema_context.vocabularies.contains(
-            "http://json-schema.org/draft-07/schema#")) {
+    if (context.mode == SchemaCompilerMode::FastValidation &&
+        (schema_context.vocabularies.contains(
+             "http://json-schema.org/draft-04/schema#") ||
+         schema_context.vocabularies.contains(
+             "http://json-schema.org/draft-06/schema#") ||
+         schema_context.vocabularies.contains(
+             "http://json-schema.org/draft-07/schema#"))) {
       return compile(context, new_schema_context, dynamic_context,
                      empty_pointer, empty_pointer, reference.destination);
     } else {

src/jsonschema/default_compiler_draft7.h

@@ -66,6 +66,8 @@ auto compiler_draft7_applicator_if(
 }
 
 // We handle `then` as part of `if`
+// TODO: Stop collapsing this keyword on exhaustive mode for debuggability
+// purposes
 auto compiler_draft7_applicator_then(const SchemaCompilerContext &,
                                      const SchemaCompilerSchemaContext &,
                                      const SchemaCompilerDynamicContext &)
@@ -74,6 +76,8 @@ auto compiler_draft7_applicator_then(const SchemaCompilerContext &,
 }
 
 // We handle `else` as part of `if`
+// TODO: Stop collapsing this keyword on exhaustive mode for debuggability
+// purposes
 auto compiler_draft7_applicator_else(const SchemaCompilerContext &,
                                      const SchemaCompilerSchemaContext &,
                                      const SchemaCompilerDynamicContext &)

test/evaluator/evaluator_draft4_test.cc

@@ -378,6 +378,41 @@ TEST(JSONSchema_evaluator_draft4, ref_2) {
       "The string value was expected to validate against the given subschema");
 }
 
+TEST(JSONSchema_evaluator_draft4, ref_2_exhaustive) {
+  const sourcemeta::jsontoolkit::JSON schema{
+      sourcemeta::jsontoolkit::parse(R"JSON({
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "allOf": [ { "$ref": "#/definitions/string" } ],
+    "definitions": {
+      "string": { "type": "string" }
+    }
+  })JSON")};
+
+  const sourcemeta::jsontoolkit::JSON instance{"foo"};
+
+  EVALUATE_WITH_TRACE_EXHAUSTIVE_SUCCESS(schema, instance, 3);
+
+  EVALUATE_TRACE_PRE(0, LogicalAnd, "/allOf", "#/allOf", "");
+  EVALUATE_TRACE_PRE(1, LogicalAnd, "/allOf/0/$ref", "#/allOf/0/$ref", "");
+  EVALUATE_TRACE_PRE(2, AssertionTypeStrict, "/allOf/0/$ref/type",
+                     "#/definitions/string/type", "");
+
+  EVALUATE_TRACE_POST_SUCCESS(0, AssertionTypeStrict, "/allOf/0/$ref/type",
+                              "#/definitions/string/type", "");
+  EVALUATE_TRACE_POST_SUCCESS(1, LogicalAnd, "/allOf/0/$ref", "#/allOf/0/$ref",
+                              "");
+  EVALUATE_TRACE_POST_SUCCESS(2, LogicalAnd, "/allOf", "#/allOf", "");
+
+  EVALUATE_TRACE_POST_DESCRIBE(instance, 0,
+                               "The value was expected to be of type string");
+  EVALUATE_TRACE_POST_DESCRIBE(instance, 1,
+                               "The string value was expected to validate "
+                               "against the statically referenced schema");
+  EVALUATE_TRACE_POST_DESCRIBE(
+      instance, 2,
+      "The string value was expected to validate against the given subschema");
+}
+
 TEST(JSONSchema_evaluator_draft4, ref_3) {
   const sourcemeta::jsontoolkit::JSON schema{
       sourcemeta::jsontoolkit::parse(R"JSON({