refs #2169 - mark invalid a null 'version' keyword

modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/util/OpenAPIDeserializer.java

@@ -1153,27 +1153,32 @@ public ExternalDocumentation getExternalDocs(ObjectNode node, String location, P
 
 	public String getString(String key, ObjectNode node, boolean required, String location, ParseResult
 			result, Set<String> uniqueValues, boolean noInvalidError) {
-		String value = null;
-		JsonNode v = node.get(key);
-		if (node == null || v == null) {
-			if (required) {
-				result.missing(location, key);
-				result.invalid();
-			}
-		} else if (!v.isValueNode()) {
-			if (!noInvalidError) {
-				result.invalidType(location, key, "string", node);
-			}
-        } else if (!v.isNull()) {
-			value = v.asText();
-			if (uniqueValues != null && !uniqueValues.add(value)) {
-				result.unique(location, "operationId");
-				result.invalid();
-			}
-		}
-		return value;
+		return getString(key, node, required, location, result, uniqueValues, noInvalidError, false);
 	}
 
+    public String getString(String key, ObjectNode node, boolean required, String location, ParseResult
+            result, Set<String> uniqueValues, boolean noInvalidError, boolean missingForNullNode) {
+        String value = null;
+        JsonNode v = node.get(key);
+        if (node == null || v == null || (v.isNull() && missingForNullNode)) {
+            if (required) {
+                result.missing(location, key);
+                result.invalid();
+            }
+        } else if (!v.isValueNode()) {
+            if (!noInvalidError) {
+                result.invalidType(location, key, "string", node);
+            }
+        } else if (!v.isNull()) {
+            value = v.asText();
+            if (uniqueValues != null && !uniqueValues.add(value)) {
+                result.unique(location, "operationId");
+                result.invalid();
+            }
+        }
+        return value;
+    }
+
 	public String getString(String key, ObjectNode node, boolean required, String location, ParseResult
 			result, Set<String> uniqueValues) {
 		return getString(key, node, required, location, result, uniqueValues, false);
@@ -1289,7 +1294,7 @@ public Info getInfo(ObjectNode node, String location, ParseResult result) {
 			info.setLicense(license);
 		}
 
-		value = getString("version", node, true, location, result);
+		value = getString("version", node, true, location, result, null, false, true);
 		if ((result.isAllowEmptyStrings() && value != null) || (!result.isAllowEmptyStrings() && !StringUtils.isBlank(value))) {
 			info.setVersion(value);
 		}

modules/swagger-parser-v3/src/test/java/io/swagger/v3/parser/test/OpenAPIV3ParserTest.java

@@ -3421,4 +3421,12 @@ public void testStyleAndExplodeExplicit(){
         assertEquals(openAPI.getPaths().get("/test").getPost().getRequestBody().getContent().get("multipart/form-data").getEncoding().get("fileWithout").getStyle().toString(), "form");
         assertNull(openAPI.getPaths().get("/test").getPost().getRequestBody().getContent().get("multipart/form-data").getEncoding().get("fileWithout").getExplode());
     }
+
+    @Test(description = "null version should cause a message")
+    public void testVersion(){
+        ParseOptions options = new ParseOptions();
+        OpenAPIV3Parser openApiParser = new OpenAPIV3Parser();
+        SwaggerParseResult parseResult = openApiParser.readLocation("version-missing.yaml", null, options);
+        assertEquals(parseResult.getMessages().get(0), "attribute info.version is missing");
+    }
 }

modules/swagger-parser-v3/src/test/resources/version-missing.yaml

@@ -0,0 +1,5 @@
+openapi: 3.0.3
+info:
+  title: Example API with Style and Explode
+  version: 
+paths: {}