prepare 4.0.0 and improve the generated C++ code

.github/workflows/ci.yml

@@ -43,6 +43,15 @@ jobs:
         run: |
           make examples
 
+      - name: Check that the generated code and the examples build with -Wall -Werror
+        run: |
+          for f in examples/*/*.cpp; do
+            echo "Checking $f"
+            g++ -Wall -Werror -fsyntax-only \
+              -I"$JAVA_HOME/include" -I"$JAVA_HOME/include/linux" \
+              -I"$(dirname "$f")" "$f"
+          done
+
   package:
     runs-on: ubuntu-latest
     strategy:

CHANGELOG

@@ -1,4 +1,4 @@
-giws (3.1.0)
+giws (4.0.0)
 
      * Generated code: the exception check after the Java call was only
        emitted for static methods. Non-static methods now detect a pending
@@ -14,13 +14,26 @@ giws (3.1.0)
      * Generated GiwsException: check for pending exceptions after each
        CallObjectMethod (fixes -Xcheck:jni warnings while building the
        C++ exception)
+     * Generated GiwsException: release the JNI local references on the
+       early-return paths too (they leaked when embedding the JVM, as
+       local references are only freed when the thread detaches)
+     * Generated code: boolean arrays with --disable-return-size-array
+       wrote the array length through an uninitialized pointer
+       (undefined behavior); use a local variable like the other types
+     * Generated classes: make the destructor virtual (the class has
+       virtual methods; deleting through it was flagged by
+       -Wdelete-non-virtual-dtor)
+     * Examples: fix the -Wall warnings in the hand-written sources
+       (unused variables, VLA, catching a polymorphic type by value)
+     * CI: check that the generated code and the examples build with
+       -Wall -Werror
      * Add a test suite (tests/) run by CI; no JDK needed
      * New example bug_nonstatic_exception demonstrating the exception
        fix on non-static methods
      * Modernize the Python code (f-strings, type hints, with-statement)
      * Add a pre-commit configuration running ruff
 
- -- Sylvestre Ledru <sylvestre@debian.org>  Thu, 06 Aug 2026 22:23:44 +0200
+ -- Sylvestre Ledru <sylvestre@debian.org>  Fri, 07 Aug 2026 10:43:07 +0200
 
 giws (2.0.3)
 

CXXException.py

@@ -403,7 +403,8 @@ def generateCXXBody(self, config):
 
                         // retrieve information from the exception.
                         // get method id
-                        jmethodID getLocalizedMessageId = curEnv->GetMethodID(curEnv->GetObjectClass(javaException),
+                        jclass javaExceptionClass = curEnv->GetObjectClass(javaException);
+                        jmethodID getLocalizedMessageId = curEnv->GetMethodID(javaExceptionClass,
                                                                                            "getLocalizedMessage",
                                                                                            "()Ljava/lang/String;");
 
@@ -413,18 +414,21 @@ def generateCXXBody(self, config):
         if (curEnv->ExceptionCheck())
         {
           curEnv->ExceptionClear();
+          curEnv->DeleteLocalRef(javaExceptionClass);
           return "";
         }
 
         if (description == NULL)
         {
+          curEnv->DeleteLocalRef(javaExceptionClass);
           return "";
         }
 
         std::string res = convertJavaString(curEnv, description);
 
         // release java resources
         curEnv->DeleteLocalRef(description);
+        curEnv->DeleteLocalRef(javaExceptionClass);
 
         return res;
   }
@@ -441,9 +445,11 @@ def generateCXXBody(self, config):
         // retrieve information from the exception.
         // get method id
         // getStackTrace returns an array of StackTraceElement
-        jmethodID getStackTraceId = curEnv->GetMethodID(curEnv->GetObjectClass(javaException),
+        jclass javaExceptionClass = curEnv->GetObjectClass(javaException);
+        jmethodID getStackTraceId = curEnv->GetMethodID(javaExceptionClass,
                                                                                                         "getStackTrace",
                                                                                                         "()[Ljava/lang/StackTraceElement;");
+        curEnv->DeleteLocalRef(javaExceptionClass);
 
         // call getStackTrace
         jobjectArray stackTrace = (jobjectArray) curEnv->CallObjectMethod(javaException, getStackTraceId);
@@ -536,6 +542,8 @@ def generateCXXBody(self, config):
 
         if (javaName == NULL)
         {
+          curEnv->DeleteLocalRef(exceptionClass);
+          curEnv->DeleteLocalRef(classClass);
           return "";
         }
 

classRepresentation/objectGiws.py

@@ -428,7 +428,7 @@ def generateCXXHeader(self, packageName):
 
 			%s
 			// Destructor
-			~%s();
+			virtual ~%s();
 
 			// Generic method
 			// Synchronization methods

configGiws.py

@@ -36,7 +36,7 @@
 
 """Configuration of the Env"""
 
-__version__ = "3.1.0"
+__version__ = "4.0.0"
 
 
 class configGiws:

datatypes/booleanDataGiws.py

@@ -107,12 +107,17 @@ def specificPostProcessing(self, detachThread):
         if self.isArray():
             str = JNIFrameWork().getExceptionCheckProfile(detachThread)
             strCommon = ""
+            strDeclaration = ""
             if configGiws().getDisableReturnSize() is True:
-                strCommon += "int *lenRow;"
+                strCommon += "int lenRow;"
+            else:
+                # The size of the array is returned as output argument of the
+                # function
+                strDeclaration = "*"
             strCommon += """
-			*lenRow = curEnv->GetArrayLength(res);
+			%s lenRow = curEnv->GetArrayLength(res);
 			jboolean isCopy = JNI_FALSE;
-			"""
+			""" % (strDeclaration)
 
             if self.getDimensionArray() == 1:
                 return (
@@ -122,37 +127,45 @@ def specificPostProcessing(self, detachThread):
 
 				/* faster than getXXXArrayElements */
 				jboolean *resultsArray = static_cast<jboolean *>(curEnv->GetPrimitiveArrayCritical(res, &isCopy));
-				bool * myArray= new bool[*lenRow];
+				bool * myArray= new bool[%s lenRow];
 
-				for (jsize i = 0; i < *lenRow; i++){
+				for (jsize i = 0; i < %s lenRow; i++){
 				myArray[i]=(resultsArray[i] == JNI_TRUE);
 				}
 				curEnv->ReleasePrimitiveArrayCritical(res, resultsArray, JNI_ABORT);
 
 				curEnv->DeleteLocalRef(res);
 				"""
+                    % (strDeclaration, strDeclaration)
                 )
             else:
                 if configGiws().getDisableReturnSize() is True:
-                    str += "int *lenCol;"
+                    str += "int lenCol;"
                 return (
                     str
                     + strCommon
                     + """
-				bool ** myArray = new bool*[*lenRow];
-				for(int i=0; i<*lenRow; i++) {
+				bool ** myArray = new bool*[%s lenRow];
+				for(int i=0; i<%s lenRow; i++) {
 				jbooleanArray oneDim = (jbooleanArray)curEnv->GetObjectArrayElement(res, i);
-				*lenCol=curEnv->GetArrayLength(oneDim);
+				%s lenCol=curEnv->GetArrayLength(oneDim);
 				bool *resultsArray = static_cast<bool *>(curEnv->GetPrimitiveArrayCritical(oneDim, &isCopy));
-				myArray[i] = new bool[*lenCol];
-				for(int j=0; j<*lenCol; j++) {
+				myArray[i] = new bool[%s lenCol];
+				for(int j=0; j<%s lenCol; j++) {
 				myArray[i][j]=(resultsArray[j] == JNI_TRUE);
 				}
 				curEnv->ReleasePrimitiveArrayCritical(res, resultsArray, JNI_ABORT);
 				}
 
 				curEnv->DeleteLocalRef(res);
 				"""
+                    % (
+                        strDeclaration,
+                        strDeclaration,
+                        strDeclaration,
+                        strDeclaration,
+                        strDeclaration,
+                    )
                 )
 
         else:

examples/bug_disable_return/main.cpp

@@ -2,7 +2,7 @@
 #include "Plop.hxx"
 #include <jni.h>
 /*
-Copyright or © or Copr. INRIA/Scilab - Sylvestre LEDRU
+Copyright or � or Copr. INRIA/Scilab - Sylvestre LEDRU
 #
 Sylvestre LEDRU - <sylvestre.ledru@inria.fr> <sylvestre@ledru.info>
 
@@ -64,5 +64,6 @@ int main(){
   	JavaVM* jvm = create_vm();
 	Plop *plop = new Plop(jvm);
 	cout << "Does nothing. It is just to test the bug." << endl;
+	delete plop;
 	return 0;
 }

examples/bug_no_param_int_array/main.cpp

@@ -2,7 +2,7 @@
 #include "Bar.hxx"
 #include <jni.h>
 /*
-Copyright or © or Copr. INRIA/Scilab - Sylvestre LEDRU
+Copyright or � or Copr. INRIA/Scilab - Sylvestre LEDRU
 #
 Sylvestre LEDRU - <sylvestre.ledru@inria.fr> <sylvestre@ledru.info>
 
@@ -64,5 +64,6 @@ int main(){
   	JavaVM* jvm = create_vm();
 	Bar *plop = new Bar(jvm);
 	cout << "Does nothing" << endl;
+	delete plop;
 	return 0;
 }

examples/example2/main.cpp

@@ -1,5 +1,5 @@
 /*
-Copyright or © or Copr. INRIA/Scilab - Sylvestre LEDRU
+Copyright or � or Copr. INRIA/Scilab - Sylvestre LEDRU
 #
 Sylvestre LEDRU - <sylvestre.ledru@inria.fr> <sylvestre@ledru.info>
 
@@ -61,7 +61,7 @@ using namespace example2;
 using namespace std;
 
 int main(){
-	int sizeArray=3;
+	const int sizeArray=3;
   	JavaVM* jvm = create_vm();
 	MyObjectWithArray *plop = new MyObjectWithArray(jvm);
 	int myArrayOfLong[sizeArray];

examples/example3/main.cpp

@@ -1,5 +1,5 @@
 /*
-Copyright or © or Copr. INRIA/Scilab - Sylvestre LEDRU
+Copyright or � or Copr. INRIA/Scilab - Sylvestre LEDRU
 #
 Sylvestre LEDRU - <sylvestre.ledru@inria.fr> <sylvestre@ledru.info>
 
@@ -63,7 +63,6 @@ using namespace example3;
 using namespace std;
 
 int main(){
-	int sizeArray=3;
   	JavaVM* jvm = create_vm();
 	MyObjectWhichReturnsExceptions *plop = new MyObjectWhichReturnsExceptions(jvm);
 
@@ -74,9 +73,9 @@ int main(){
 
 	cout << "Exception caught:" << endl;
 	try {
-		int myIntsWithExceptionCatched = plop->getIntFromArrayOfSizeThree(22);
+		plop->getIntFromArrayOfSizeThree(22);
 
-	}catch(GiwsException::JniException e) {
+	}catch(const GiwsException::JniException & e) {
 		cout << "getJavaDescription: " << e.getJavaDescription() << endl;
 		cout << "getJavaStackTrace: " << e.getJavaStackTrace() << endl;
 		cout << "getJavaExceptionName: " << e.getJavaExceptionName() << endl;
@@ -86,8 +85,8 @@ int main(){
 
 	cout << "Exception will be trigger. This will display the message of the exception" << endl;
 	try {
-		int value = plop->thisMethodWillFailWithMessage();
-	}catch(GiwsException::JniException e) {
+		plop->thisMethodWillFailWithMessage();
+	}catch(const GiwsException::JniException & e) {
 		cout << "getJavaDescription: " << e.getJavaDescription() << endl;
 		cout << "getJavaStackTrace: " << e.getJavaStackTrace() << endl;
 		cout << "getJavaExceptionName: " << e.getJavaExceptionName() << endl;
@@ -96,7 +95,7 @@ int main(){
 	cout << "========================" << endl;
 
 	cout << "Exception not caught:" << endl;
-	int myIntsWithException = plop->getIntFromArrayOfSizeThree(223);
+	plop->getIntFromArrayOfSizeThree(223);
 	cout << "Value from the Java with good pos : " << myInts  <<endl;
 
 	return 0;

examples/inherit/showcase.cpp

@@ -13,5 +13,6 @@ class Son : public Father {
 int main(){
 
 	Son *son = new Son();
+	delete son;
 	return 0;
 }