resolving #217 by changing spec version deduction mechanism so that it considers explicitly set spec version if the value of $schema cannot be resolved to any spec versions

Author: erosb

core/src/main/java/org/everit/json/schema/loader/SchemaLoader.java

@@ -62,6 +62,8 @@ public static class SchemaLoaderBuilder {
 
         SpecificationVersion specVersion;
 
+        private boolean specVersionIsExplicitlySet = false;
+
         boolean useDefaults = false;
 
         private boolean nullableSupport = false;
@@ -105,11 +107,13 @@ public SchemaLoaderBuilder addFormatValidator(String formatName,
 
         public SchemaLoaderBuilder draftV6Support() {
             setSpecVersion(DRAFT_6);
+            specVersionIsExplicitlySet = true;
             return this;
         }
 
         public SchemaLoaderBuilder draftV7Support() {
             setSpecVersion(DRAFT_7);
+            specVersionIsExplicitlySet = true;
             return this;
         }
 
@@ -125,7 +129,7 @@ private Optional<SpecificationVersion> specVersionInSchema() {
                 try {
                     specVersion = Optional.ofNullable(metaSchemaURL).map((SpecificationVersion::getByMetaSchemaUrl));
                 } catch (IllegalArgumentException e) {
-                    throw new SchemaException("#", e.getMessage());
+                    return specVersion;
                 }
             }
             return specVersion;
@@ -275,9 +279,21 @@ public SchemaLoader(SchemaLoaderBuilder builder) {
         Object effectiveRootSchemaJson = builder.rootSchemaJson == null
                 ? builder.schemaJson
                 : builder.rootSchemaJson;
-        SpecificationVersion specVersion = extractSchemaKeywordValue(effectiveRootSchemaJson)
-                .map(SpecificationVersion::getByMetaSchemaUrl)
-                .orElse(builder.specVersion);
+        Optional<String> schemaKeywordValue = extractSchemaKeywordValue(effectiveRootSchemaJson);
+        SpecificationVersion specVersion;
+        if (schemaKeywordValue.isPresent()) {
+            try {
+                specVersion = SpecificationVersion.getByMetaSchemaUrl(schemaKeywordValue.get());
+            } catch (IllegalArgumentException e) {
+                if (builder.specVersionIsExplicitlySet) {
+                    specVersion = builder.specVersion;
+                } else {
+                    throw new SchemaException("#", "could not determine version");
+                }
+            }
+        } else {
+            specVersion = builder.specVersion;
+        }
         this.config = new LoaderConfig(builder.httpClient,
                 builder.formatValidators,
                 specVersion,

core/src/main/java/org/everit/json/schema/loader/SpecificationVersion.java

@@ -155,7 +155,7 @@ private static List<String> keywords(String... keywords) {
 
     private static Map<String, FormatValidator> formatValidators(Map<String, FormatValidator> parent, FormatValidator... validators) {
         Map<String, FormatValidator> validatorMap = (parent == null) ? new HashMap<>() : new HashMap<>(parent);
-        for(FormatValidator validator : validators) {
+        for (FormatValidator validator : validators) {
             validatorMap.put(validator.formatName(), validator);
         }
         return unmodifiableMap(validatorMap);

core/src/test/java/org/everit/json/schema/loader/SchemaLoaderTest.java

@@ -61,7 +61,7 @@ public class SchemaLoaderTest {
 
     private static JSONObject ALL_SCHEMAS = ResourceLoader.DEFAULT.readObj("testschemas.json");
 
-    private static JSONObject get(final String schemaName) {
+    private static JSONObject get(String schemaName) {
         return ALL_SCHEMAS.getJSONObject(schemaName);
     }
 

core/src/test/java/org/everit/json/schema/loader/SpecVersionDeductionTest.java

@@ -0,0 +1,71 @@
+package org.everit.json.schema.loader;
+
+import static org.everit.json.schema.loader.SpecificationVersion.DRAFT_4;
+import static org.everit.json.schema.loader.SpecificationVersion.DRAFT_6;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.fail;
+
+import org.everit.json.schema.ResourceLoader;
+import org.everit.json.schema.SchemaException;
+import org.json.JSONObject;
+import org.junit.Test;
+
+public class SpecVersionDeductionTest {
+
+    private static JSONObject ALL_SCHEMAS = ResourceLoader.DEFAULT.readObj("testschemas.json");
+
+    private static JSONObject get(String schemaName) {
+        return ALL_SCHEMAS.getJSONObject(schemaName);
+    }
+
+    private void assertSchemaException(SchemaLoader.SchemaLoaderBuilder loaderBuilder) {
+        try {
+            loaderBuilder.build();
+            fail("did not throw exception");
+        } catch (SchemaException e) {
+            assertEquals("#", e.getSchemaLocation());
+        }
+    }
+
+    private void assertSpecVersion(SpecificationVersion version, SchemaLoader.SchemaLoaderBuilder loaderBuilder) {
+        assertSame(version, loaderBuilder.build().specVersion());
+    }
+
+    @Test
+    public void unknownMetaSchema_implicitDefault() {
+        assertSchemaException(SchemaLoader.builder().schemaJson(get("unknownMetaSchema")));
+    }
+
+    @Test
+    public void knownMetaSchema_implicitDefault() {
+        assertSpecVersion(DRAFT_6, SchemaLoader.builder().schemaJson(get("explicitSchemaVersion")));
+    }
+
+    @Test
+    public void missingMetaSchema_implicitDefault() {
+        assertSpecVersion(DRAFT_4, SchemaLoader.builder().schemaJson(get("constSchema")));
+    }
+
+    @Test
+    public void unknownMetaSchema_explicitDefault() {
+        assertSpecVersion(DRAFT_6, SchemaLoader.builder()
+                .draftV6Support()
+                .schemaJson(get("unknownMetaSchema")));
+    }
+
+    @Test
+    public void knownMetaSchema_explicitDefault() {
+        assertSpecVersion(DRAFT_6, SchemaLoader.builder()
+                .draftV7Support()
+                .schemaJson(get("explicitSchemaVersion")));
+    }
+
+    @Test
+    public void missingMetaSchema_explicitDefault() {
+        assertSpecVersion(DRAFT_6, SchemaLoader.builder()
+                .draftV6Support()
+                .schemaJson(get("constSchema")));
+    }
+
+}