Python Coverage For C++ Pyimport

Situation: I'm attempting to get coverage reports on all python code in my current project. I've utilized Coverage.py with great success for the most part. Currently I'm using it l

Solution 1:

I reproduced the issue using your code and you only forgot to call Py_Finalize(). As a result, the report is never generated whereas the data were collected.

It works with the following piece of code:

#include<stdio.h>#include<iostream>#include<Python.h>intmain(){
    Py_Initialize();
    PyEval_InitThreads();
    PyObject* sysPath = PySys_GetObject("path");
    PyList_Append(sysPath, PyString_FromString("."));
    // Load the module
    PyObject *pName = PyString_FromString("test_mod");
    PyObject *pModule = PyImport_Import(pName);
    if (pModule != NULL) {
        std::cout << "Python module found\n";
        // Load all module level attributes as a dictionary
        PyObject *pDict = PyModule_GetDict(pModule);
        PyObject *pFunc = PyObject_GetAttrString(pModule, "getInteger");
        if(pFunc)
        {
            if(PyCallable_Check(pFunc))
            {
                PyObject *pValue = PyObject_CallObject(pFunc, NULL);
                std::cout << PyLong_AsLong(pValue) << std::endl;
            }
            else
            {
                printf("ERROR: function getInteger()\n");
            }

        }
        else
        {
            printf("ERROR: pFunc is NULL\n");
        }
    }
    else
        std::cout << "Python Module not found\n";
    Py_Finalize();
    return0;

Solution 2:

PyObject *PySys_GetObject(char *name) returns a borrowed reference. Is not it the case that the reference count should be incremented? What about:

// ...
PyObject* sysPath = PySys_GetObject("path");
Py_INCREF(sysPath);
PyList_Append(sysPath, PyString_FromString("."));
Py_DECREF(sysPath);
// sysPath = NULL;// ...

Solution 3:

I'm only just starting with the Python-C API myself, but my understanding is that importing modules doesn't actually add them to your main module. You need to do that separately. I'm not sure if this will help with your issue, but my approach that's worked (minus the error checking) has been as follows:

// Initialize main module
PyObject* mainModule = PyImport_AddModule("__main__");;

//  Initialize module to be added
PyObject* moduleNamePyObject= PyUnicode_DecodeFSDefault("moduleName");
PyImport_Import(moduleNamePyObject);

// Add module to main modulePyObject_SetAttrString(mainModulePtr, "moduleName", modulePyObject);

Solution 4:

Normally, when importing a module, Python tries to find the module file next to the importing module (the module that contains the import statement). Python then tries the directories in “sys.path”. The current working directory is usually not considered. In our case, the import is performed via the API, so there is no importing module in whose directory Python could search for “test_mod.py”. The plug-in is also not on “sys.path”. One way of enabling Python to find the plug-in is to add the current working directory to the module search path by doing the equivalent of “sys.path.append(‘.’)” via the API.

Py_Initialize();
PyObject* sysPath = PySys_GetObject((char*)"path");
PyObject* programName = PyString_FromString(<DIRECTORY>.c_str());
PyList_Append(sysPath, programName);
Py_DECREF(programName);

If you are using python3 ,

Change PyString_FromString to PyUnicode_FromString.

Sources :

https://realmike.org/blog/2012/07/08/embedding-python-tutorial-part-1/

Python Embedding: PyImport_Import not from the current directory