fix(class): throw error when class is extending itself

packages/concerto-core/lib/introspect/classdeclaration.js

@@ -200,6 +200,19 @@ class ClassDeclaration extends Declaration {
 
         // if we have a super type make sure it exists
         if (this.superType !== null) {
+            // and make sure that the class isn't extending itself
+            // (an exemption is made for the core classes)
+            if (
+                this.superType === this.name &&
+                ![
+                    'Asset', 'Concept', 'Event', 'Participant', 'Transaction',
+                ].includes(this.superType)
+            ) {
+                let formatter = Globalize('en').messageFormatter('classdeclaration-validate-selfextending');
+                throw new IllegalModelException(formatter({
+                    'class': this.name,
+                }), this.modelFile, this.ast.location);
+            }
             this._resolveSuperType();
         }
 

packages/concerto-core/messages/en.json

@@ -20,6 +20,7 @@
         "classdeclaration-validate-identifiernotstring": "Class \"{class}\" is identified by field \"{idField}\", but the type of the field is not \"String\".",
         "classdeclaration-validate-duplicatefieldname": "Class \"{class}\" has more than one field named \"{fieldName}\".",
         "classdeclaration-validate-missingidentifier" : "Class \"{class}\" is not declared as \"abstract\". It must define an identifying field.",
+        "classdeclaration-validate-selfextending": "Class \"{class}\" cannot extend itself.",
 
         "modelfile-constructor-unrecmodelelem": "Unrecognised model element \"{type}\".",
         "modelfile-resolvetype-undecltype": "Undeclared type \"{type}\" in \"{context}\".",

packages/concerto-cto/lib/parser.pegjs

@@ -966,6 +966,9 @@ AssetDeclaration
         ...buildRange(location())
       };
       if (classExtension) {
+        if (classExtension.name === id.name) {
+            throw new Error(`The asset "${id.name}" cannot extend itself.`);
+        }
         result.superType = classExtension;
       }
       if (idField) {
@@ -989,6 +992,9 @@ ParticipantDeclaration
         ...buildRange(location())
       };
       if (classExtension) {
+        if (classExtension.name === id.name) {
+          throw new Error(`The participant "${id.name}" cannot extend itself.`);
+        }
         result.superType = classExtension;
       }
       if (idField) {
@@ -1012,6 +1018,9 @@ TransactionDeclaration
         ...buildRange(location())
       };
       if (classExtension) {
+        if (classExtension.name === id.name) {
+          throw new Error(`The transaction "${id.name}" cannot extend itself.`);
+        }
         result.superType = classExtension;
       }
       if (idField) {
@@ -1035,6 +1044,9 @@ EventDeclaration
         ...buildRange(location())
       };
       if (classExtension) {
+        if (classExtension.name === id.name) {
+          throw new Error(`The event "${id.name}" cannot extend itself.`);
+        }
         result.superType = classExtension;
       }
       if (idField) {
@@ -1058,6 +1070,9 @@ ConceptDeclaration
         ...buildRange(location())
       };
       if (classExtension) {
+        if (classExtension.name === id.name) {
+          throw new Error(`The concept "${id.name}" cannot extend itself.`);
+        }
         result.superType = classExtension;
       }
       if (idField) {

packages/concerto-cto/lib/printer.js

@@ -343,6 +343,9 @@ function declFromMetaModel(mm) {
             }
         }
         if (mm.superType) {
+            if (mm.superType.name === mm.name) {
+                throw new Error(`The declaration "${mm.name}" cannot extend itself.`);
+            }
             result += `extends ${mm.superType.name} `;
         }
         result += '{';

packages/concerto-cto/test/cto/bad/self-extending-asset.bad.cto

@@ -0,0 +1,5 @@
+namespace [email protected]
+
+asset Self_Extending extends Self_Extending {
+  o String foo optional
+}

packages/concerto-cto/test/cto/bad/self-extending-concept.bad.cto

@@ -0,0 +1,5 @@
+namespace [email protected]
+
+concept Self_Extending extends Self_Extending {
+  o String foo optional
+}

packages/concerto-cto/test/cto/bad/self-extending-event.bad.cto

@@ -0,0 +1,5 @@
+namespace [email protected]
+
+event Self_Extending extends Self_Extending {
+  o String foo optional
+}

packages/concerto-cto/test/cto/bad/self-extending-participant.bad.cto

@@ -0,0 +1,5 @@
+namespace [email protected]
+
+participant Self_Extending extends Self_Extending {
+  o String foo optional
+}

packages/concerto-cto/test/cto/bad/self-extending-transaction.bad.cto

@@ -0,0 +1,5 @@
+namespace [email protected]
+
+transaction Self_Extending extends Self_Extending {
+  o String foo optional
+}

packages/concerto-cto/test/parserMain.js

@@ -81,6 +81,24 @@ describe('parser', () => {
         });
     });
 
+    describe('self-extending', () => {
+        const declarationTypes = [
+            'asset',
+            'participant',
+            'transaction',
+            'event',
+            'concept',
+        ];
+        declarationTypes.forEach(declarationType => {
+            it(`Should not parse a self-extending ${declarationType}`, () => {
+                let content = fs.readFileSync(`./test/cto/bad/self-extending-${declarationType}.bad.cto`, 'utf8');
+                (() => {
+                    Parser.parse(content);
+                }).should.throw(new RegExp(`The ${declarationType} ".+" cannot extend itself.`));
+            });
+        });
+    });
+
     describe('identifiers', () => {
 
         const acceptedIdentifiers = [

packages/concerto-cto/test/printer.js

@@ -62,4 +62,30 @@ describe('parser', () => {
             declarations: [],
         })).should.throw(Error, 'Unrecognized import');
     });
+
+    it('Should throw error for a self-extending declaration', () => {
+        (() => Printer.toCTO({
+            '$class': '[email protected]',
+            'namespace': '[email protected]',
+            'declarations': [
+                {
+                    '$class': '[email protected]',
+                    'name': 'Self_Extending',
+                    'isAbstract': false,
+                    'properties': [
+                        {
+                            '$class': '[email protected]',
+                            'name': 'foo',
+                            'isArray': false,
+                            'isOptional': true
+                        }
+                    ],
+                    'superType': {
+                        '$class': '[email protected]',
+                        'name': 'Self_Extending'
+                    }
+                }
+            ]
+        })).should.throw(Error, 'The declaration "Self_Extending" cannot extend itself.');
+    });
 });