Make getting globals/locals thread safe

src/main/c/jni/org_jpy_PyLib.c

@@ -521,6 +521,7 @@ PyObject *getMainGlobals() {
  }
 
  pyGlobals = PyModule_GetDict(pyMainModule); // borrowed ref
+ JPy_INCREF(pyGlobals);
 
  return pyGlobals;
 }
@@ -532,7 +533,7 @@ JNIEXPORT jobject JNICALL Java_org_jpy_PyLib_getMainGlobals
 
  JPy_BEGIN_GIL_STATE
 
- globals = getMainGlobals(); // borrowed ref
+ globals = getMainGlobals(); // new ref
  if (globals == NULL) {
  goto error;
  }
@@ -543,6 +544,7 @@ JNIEXPORT jobject JNICALL Java_org_jpy_PyLib_getMainGlobals
  }
 
 error:
+ JPy_XDECREF(globals);
  JPy_END_GIL_STATE
 
  return objectRef;
@@ -555,10 +557,12 @@ JNIEXPORT jobject JNICALL Java_org_jpy_PyLib_getCurrentGlobals
 
  JPy_BEGIN_GIL_STATE
 
-#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION > 12
- globals = PyEval_GetFrameGlobals(); // new ref
-#else
+#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION <= 12
  globals = PyEval_GetGlobals(); // borrowed ref
+ JPy_INCREF(globals);
+#else
+ // See https://peps.python.org/pep-0667 for the change in Python 3.13
+ globals = PyEval_GetFrameGlobals(); // new ref
 #endif
 
  if (globals == NULL) {
@@ -571,11 +575,9 @@ JNIEXPORT jobject JNICALL Java_org_jpy_PyLib_getCurrentGlobals
  }
 
 error:
-#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION > 12
  JPy_XDECREF(globals);
-#endif
-
  JPy_END_GIL_STATE
+
  return objectRef;
 }
 
@@ -586,10 +588,12 @@ JNIEXPORT jobject JNICALL Java_org_jpy_PyLib_getCurrentLocals
 
  JPy_BEGIN_GIL_STATE
 
-#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION > 12
- locals = PyEval_GetFrameLocals(); // new ref
+#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION <= 12
+ locals = PyEval_GetLocals(); // borrowed ref
+ JPy_INCREF(locals);
 #else
- locals = PyEval_GetLocals(); // borrowed ref
+ // See https://peps.python.org/pep-0667 for the change in Python 3.13
+ locals = PyEval_GetFrameLocals(); // new ref
 #endif
 
  if (locals == NULL) {
@@ -602,11 +606,9 @@ JNIEXPORT jobject JNICALL Java_org_jpy_PyLib_getCurrentLocals
  }
 
 error:
-#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION > 12
  JPy_XDECREF(locals);
-#endif
-
  JPy_END_GIL_STATE
+
  return objectRef;
 }
 
@@ -919,7 +921,8 @@ jlong executeInternal(JNIEnv* jenv, jclass jLibClass, jint jStart, jobject jGlob
 
  if (jGlobals == NULL) {
  JPy_DIAG_PRINT(JPy_DIAG_F_EXEC, "Java_org_jpy_PyLib_executeInternal: using main globals\n");
- pyGlobals = getMainGlobals();
+ pyGlobals = getMainGlobals(); // new ref
+ decGlobals = JNI_TRUE;
  if (pyGlobals == NULL) {
  PyLib_HandlePythonException(jenv);
  goto error;