PyEmbedded methods to retrieve Python stack trace.

Core/Tools/PyEmbeddedUtils.cpp

@@ -38,7 +38,7 @@ std::string PyEmbeddedUtils::toString(PyObject* obj, bool decref)
     return result;
 }
 
-std::vector<std::string> PyEmbeddedUtils::toVectorString(PyObject* obj, bool decref)
+std::vector<std::string> PyEmbeddedUtils::toVectorString(PyObject* obj)
 {
     std::vector<std::string> result;
 
@@ -58,9 +58,6 @@ std::vector<std::string> PyEmbeddedUtils::toVectorString(PyObject* obj, bool dec
         throw std::runtime_error("PyEmbeddedUtils::toVectorString() -> Error. Unexpected object.");
     }
 
-    if (decref)
-        Py_DECREF(obj);
-
     return result;
 }
 
@@ -116,3 +113,79 @@ void PyEmbeddedUtils::import_bornagain(const std::string& path)
     }
 
 }
+
+std::string PyEmbeddedUtils::pythonRuntimeInfo()
+{
+    Py_InitializeEx(0);
+
+    std::stringstream result;
+
+    // Runtime environment
+    result << std::string(60, '=') << "\n";
+    result << "PATH: " << SysUtils::getenv("PATH") << "\n";
+    result << "PYTHONPATH: " << SysUtils::getenv("PYTHONPATH") << "\n";
+    result << "PYTHONHOME: " << SysUtils::getenv("PYTHONHOME") << "\n";
+
+    // Embedded Python details
+    result << "Py_GetProgramName(): "
+           << PyEmbeddedUtils::toString(Py_GetProgramName()) << "\n";
+    result << "Py_GetPath(): "
+           << PyEmbeddedUtils::toString(Py_GetPath()) << "\n";
+    result << "Py_GetProgramFullPath(): "
+           << PyEmbeddedUtils::toString(Py_GetProgramFullPath()) << "\n";
+    result << "Py_GetPythonHome(): "
+           << PyEmbeddedUtils::toString(Py_GetPythonHome()) << "\n";
+
+    // Runtime Python's sys.path
+    PyObject *sysPath = PySys_GetObject((char*)"path");
+    auto content = PyEmbeddedUtils::toVectorString(sysPath);
+    result << "sys.path: ";
+    for (auto s : content)
+        result << s << ",";
+    result << "\n";
+
+    return result.str();
+}
+
+// Attempt to retrieve Python stack trace
+// https://stackoverflow.com/questions/1796510/accessing-a-python-traceback-from-the-c-api
+
+std::string PyEmbeddedUtils::pythonStackTrace()
+{
+    std::stringstream result;
+
+    if (PyErr_Occurred()) {
+        PyObject *ptype, *pvalue, *ptraceback, *pystr;
+
+        PyErr_Fetch(&ptype, &pvalue, &ptraceback);
+        pystr = PyObject_Str(pvalue);
+        if (char* str = PyString_AsString(pystr))
+            result << std::string(str) << "\n";
+
+        PyObject* module_name = PyString_FromString("traceback");
+        PyObject* pyth_module = PyImport_Import(module_name);
+        Py_DECREF(module_name);
+
+        if (pyth_module) {
+            result << "\n";
+            PyObject* pyth_func = PyObject_GetAttrString(pyth_module, "format_exception");
+            if (pyth_func && PyCallable_Check(pyth_func)) {
+                PyObject* pyth_val;
+
+                pyth_val = PyObject_CallFunctionObjArgs(pyth_func, ptype, pvalue, ptraceback, NULL);
+
+                pystr = PyObject_Str(pyth_val);
+                if (char* str = PyString_AsString(pystr))
+                    result << std::string(str);
+                Py_DECREF(pyth_val);
+            }
+            result << "\n";
+        }
+    }
+
+    result << "\n";
+    result << pythonRuntimeInfo();
+    result << "\n";
+
+    return result.str();
+}

Core/Tools/PyEmbeddedUtils.h

@@ -33,7 +33,7 @@ BA_CORE_API_ std::string toString(PyObject* obj, bool decref = true);
 
 //! Converts PyObject into vector of strings, if possible, or throws exception.
 //! @param decref To automatically decrease reference counter after data is processed.
-BA_CORE_API_ std::vector<std::string> toVectorString(PyObject* obj, bool decref = true);
+BA_CORE_API_ std::vector<std::string> toVectorString(PyObject* obj);
 
 //! Converts char to string. In the case of nullptr will return an empty string.
 BA_CORE_API_ std::string toString(char* c);
@@ -42,6 +42,11 @@ BA_CORE_API_ std::string toString(wchar_t* c);
 //! Imports BornAgain from given location. If path is empty, tries to rely on PYTHONPATH.
 BA_CORE_API_ void import_bornagain(const std::string& path = std::string());
 
+//! Returns multi-line string representing PATH, PYTHONPATH, sys.path and other info.
+BA_CORE_API_ std::string pythonRuntimeInfo();
+
+//! Returns string representing python stack trace.
+BA_CORE_API_ std::string pythonStackTrace();
 }
 
 #endif

Core/Tools/PyImport.cpp

@@ -70,8 +70,12 @@ std::vector<std::string> PyImport::listOfFunctions(const std::string& script,
 
     // create a module
     PyObject* pModule = PyImport_ExecCodeModule((char *)"test" , pCompiledFn ) ;
-    if (!pModule)
-        throw std::runtime_error("Can't exec module");
+    if (!pModule) {
+        std::stringstream buf;
+        buf << "Can't exec module" << "\n";
+        buf << PyEmbeddedUtils::pythonStackTrace() << "\n";
+        throw std::runtime_error(buf.str());
+    }
 
      PyObject *dict = PyModule_GetDict(pModule);
      if (!dict)

GUI/coregui/mainwindow/PyImportAssistant.cpp

@@ -145,6 +145,7 @@ QString PyImportAssistant::getPySampleFunctionName(const QString& snippet)
         funcList = GUIHelpers::fromStdStrings(funcs);
 
     } catch (const std::exception& ex) {
+        QApplication::restoreOverrideCursor();
         QString message("Exception thrown while executing a Python code.\n\n");
         message += QString::fromStdString(std::string(ex.what()));
         GUIHelpers::warning(m_mainWindow, "Python failure",  message);

Tests/Functional/Python/PyEmbedded/TestCases.cpp

@@ -43,32 +43,8 @@ bool SysPath::runTest()
     // BornAgain build
     std::cout << "buildLibDir(): " << BABuild::buildLibDir() << std::endl;
 
-    // Runtime environment
-    std::cout << "PATH: " << SysUtils::getenv("PATH") << std::endl;
-    std::cout << "PYTHONPATH: " << SysUtils::getenv("PYTHONPATH") << std::endl;
-    std::cout << "PYTHONHOME: " << SysUtils::getenv("PYTHONHOME") << std::endl;
-
-    Py_Initialize();
-
-    // Embedded Python details
-    std::cout << "Py_GetProgramName(): "
-              << PyEmbeddedUtils::toString(Py_GetProgramName()) << std::endl;
-    std::cout << "Py_GetPath(): "
-              << PyEmbeddedUtils::toString(Py_GetPath()) << std::endl;
-    std::cout << "Py_GetProgramFullPath(): "
-              << PyEmbeddedUtils::toString(Py_GetProgramFullPath()) << std::endl;
-    std::cout << "Py_GetPythonHome(): "
-              << PyEmbeddedUtils::toString(Py_GetPythonHome()) << std::endl;
-
-    // Runtime Python's sys.path
-    PyObject *sysPath = PySys_GetObject((char*)"path");
-    auto content = PyEmbeddedUtils::toVectorString(sysPath);
-    std::cout << "sys.path: ";
-    for (auto s : content)
-        std::cout << s << ",";
-    std::cout << std::endl;
-
-    Py_Finalize();
+    // Runtime info
+    auto content = PyEmbeddedUtils::pythonRuntimeInfo();
 
     return !content.empty();
 }