+static
+void restore_current_thread_error_and_append_exception_chain_recursive(
+ PyObject *py_exc_value,
+ bt_self_component_class *self_component_class,
+ bt_self_component *self_component,
+ bt_self_message_iterator *self_message_iterator,
+ const char *module_name)
+{
+ PyObject *py_exc_cause_value;
+ PyObject *py_exc_type = NULL;
+ PyObject *py_exc_tb = NULL;
+ GString *gstr = NULL;
+
+ /* If this exception has a cause, handle that one first. */
+ py_exc_cause_value = PyException_GetCause(py_exc_value);
+ if (py_exc_cause_value) {
+ restore_current_thread_error_and_append_exception_chain_recursive(
+ py_exc_cause_value, self_component_class,
+ self_component, self_message_iterator, module_name);
+ }
+
+ /*
+ * If the raised exception is a bt2._Error, restore the wrapped error.
+ */
+ if (PyErr_GivenExceptionMatches(py_exc_value, py_mod_bt2_exc_error_type)) {
+ PyObject *py_error_swig_ptr;
+ const bt_error *error;
+ int ret;
+
+ /*
+ * We never raise a bt2._Error with a cause: it should be the
+ * end of the chain.
+ */
+ BT_ASSERT(!py_exc_cause_value);
+
+ /*
+ * We steal the error object from the exception, to move
+ * it back as the current thread's error.
+ */
+ py_error_swig_ptr = PyObject_GetAttrString(py_exc_value, "_ptr");
+ BT_ASSERT(py_error_swig_ptr);
+
+ ret = PyObject_SetAttrString(py_exc_value, "_ptr", Py_None);
+ BT_ASSERT(ret == 0);
+
+ ret = SWIG_ConvertPtr(py_error_swig_ptr, (void **) &error,
+ SWIGTYPE_p_bt_error, 0);
+ BT_ASSERT(ret == 0);
+
+ BT_CURRENT_THREAD_MOVE_ERROR_AND_RESET(error);
+
+ Py_DECREF(py_error_swig_ptr);
+ }
+
+ py_exc_type = PyObject_Type(py_exc_value);
+ py_exc_tb = PyException_GetTraceback(py_exc_value);
+
+ gstr = bt_py_common_format_exception(py_exc_type, py_exc_value,
+ py_exc_tb, BT_LOG_OUTPUT_LEVEL, false);
+ if (!gstr) {
+ /* bt_py_common_format_exception has already warned. */
+ goto end;
+ }
+
+ if (self_component_class) {
+ BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_COMPONENT_CLASS(
+ self_component_class, "%s", gstr->str);
+ } else if (self_component) {
+ BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_COMPONENT(
+ self_component, "%s", gstr->str);
+ } else if (self_message_iterator) {
+ BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_MESSAGE_ITERATOR(
+ self_message_iterator, "%s", gstr->str);
+ } else {
+ BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_UNKNOWN(
+ module_name, "%s", gstr->str);
+ }
+
+end:
+ if (gstr) {
+ g_string_free(gstr, TRUE);
+ }
+
+ Py_XDECREF(py_exc_cause_value);
+ Py_XDECREF(py_exc_type);
+ Py_XDECREF(py_exc_tb);
+}
+
+/*
+ * If you have the following code:
+ *
+ * try:
+ * try:
+ * something_that_raises_bt2_error()
+ * except bt2._Error as e1:
+ * raise ValueError from e1
+ * except ValueError as e2:
+ * raise TypeError from e2
+ *
+ * We will have the following exception chain:
+ *
+ * TypeError -> ValueError -> bt2._Error
+ *
+ * Where the TypeError is the current exception (obtained from PyErr_Fetch).
+ *
+ * The bt2._Error contains a `struct bt_error *` that used to be the current
+ * thread's error, at the moment the exception was raised.
+ *
+ * This function gets to the bt2._Error and restores the wrapped
+ * `struct bt_error *` as the current thread's error.
+ *
+ * Then, for each exception in the chain, starting with the oldest one, it adds
+ * an error cause to the current thread's error.
+ */
+static
+void restore_bt_error_and_append_current_exception_chain(
+ bt_self_component_class *self_component_class,
+ bt_self_component *self_component,
+ bt_self_message_iterator *self_message_iterator,
+ const char *module_name)
+{
+ BT_ASSERT(PyErr_Occurred());
+
+ /* Used to access and restore the current exception. */
+ PyObject *py_exc_type;
+ PyObject *py_exc_value;
+ PyObject *py_exc_tb;
+
+ /* Fetch and normalize the Python exception. */
+ PyErr_Fetch(&py_exc_type, &py_exc_value, &py_exc_tb);
+ PyErr_NormalizeException(&py_exc_type, &py_exc_value, &py_exc_tb);
+ BT_ASSERT(py_exc_type);
+ BT_ASSERT(py_exc_value);
+ BT_ASSERT(py_exc_tb);
+
+ /*
+ * Set the exception's traceback so it's possible to get it using
+ * PyException_GetTraceback in
+ * restore_current_thread_error_and_append_exception_chain_recursive.
+ */
+ PyException_SetTraceback(py_exc_value, py_exc_tb);
+
+ restore_current_thread_error_and_append_exception_chain_recursive(py_exc_value,
+ self_component_class, self_component, self_message_iterator,
+ module_name);
+
+ PyErr_Restore(py_exc_type, py_exc_value, py_exc_tb);
+}
+