1 files changed, 44 insertions, 3 deletions

diff --git a/source/blender/python/generic/py_capi_utils.c b/source/blender/python/generic/py_capi_utils.c
index d2e3c44c1b6..007a2fdbb8e 100644
--- a/source/blender/python/generic/py_capi_utils.c
+++ b/source/blender/python/generic/py_capi_utils.c
@@ -641,6 +641,7 @@ void PyC_StackSpit(void)
 void PyC_FileAndNum(const char **r_filename, int *r_lineno)
 {
   PyFrameObject *frame;
+  PyCodeObject *code;
 
   if (r_filename) {
     *r_filename = NULL;
@@ -649,13 +650,16 @@ void PyC_FileAndNum(const char **r_filename, int *r_lineno)
     *r_lineno = -1;
   }
 
-  if (!(frame = PyThreadState_GET()->frame)) {
+  if (!(frame = PyEval_GetFrame())) {
+    return;
+  }
+  if (!(code = PyFrame_GetCode(frame))) {
     return;
   }
 
   /* when executing a script */
   if (r_filename) {
-    *r_filename = PyUnicode_AsUTF8(frame->f_code->co_filename);
+    *r_filename = PyUnicode_AsUTF8(code->co_filename);
   }
 
   /* when executing a module */
@@ -819,6 +823,36 @@ void PyC_Err_PrintWithFunc(PyObject *py_func)
 /** \name Exception Buffer Access
  * \{ */
 
+static void pyc_exception_buffer_handle_system_exit(PyObject *error_type,
+                                                    PyObject *error_value,
+                                                    PyObject *error_traceback)
+{
+  if (!PyErr_GivenExceptionMatches(error_type, PyExc_SystemExit)) {
+    return;
+  }
+  /* Inspecting, follow Python's logic in #_Py_HandleSystemExit & treat as a regular exception. */
+  if (_Py_GetConfig()->inspect) {
+    return;
+  }
+
+  /* NOTE(@campbellbarton): A `SystemExit` exception will exit immediately (unless inspecting).
+   * So print the error and exit now. This is necessary as the call to #PyErr_Print exits,
+   * the temporary `sys.stderr` assignment causes the output to be suppressed, failing silently.
+   * Instead, restore the error and print it. If Python changes it's behavior and doesn't exit in
+   * the future - continue to create the exception buffer, see: T99966.
+   *
+   * Arguably accessing a `SystemExit` exception as a buffer should be supported without exiting.
+   * (by temporarily enabling inspection for example) however - it's not obvious exactly when this
+   * should be enabled and complicates the Python API by introducing different kinds of execution.
+   * Since the rule of thumb is for Blender's embedded Python to match stand-alone Python,
+   * favor exiting when a `SystemExit` is raised.
+   * Especially since this exception more likely to be used for background/batch-processing
+   * utilities where exiting immediately makes sense, the possibility of this being called
+   * indirectly from python-drivers or modal-operators is less of a concern. */
+  PyErr_Restore(error_type, error_value, error_traceback);
+  PyErr_Print();
+}
+
 /* returns the exception string as a new PyUnicode object, depends on external traceback module */
 #  if 0
 
@@ -869,6 +903,8 @@ PyObject *PyC_ExceptionBuffer(void)
 
   PyErr_Fetch(&error_type, &error_value, &error_traceback);
 
+  pyc_exception_buffer_handle_system_exit(error_type, error_value, error_traceback);
+
   /* import io
    * string_io = io.StringIO()
    */
@@ -892,7 +928,7 @@ PyObject *PyC_ExceptionBuffer(void)
   PySys_SetObject("stderr", string_io);
 
   PyErr_Restore(error_type, error_value, error_traceback);
-  /* Printing clears (call #PyErr_Clear as well to ensure it's cleared).  */
+  /* Printing clears (call #PyErr_Clear as well to ensure it's cleared). */
   Py_XINCREF(error_type);
   Py_XINCREF(error_value);
   Py_XINCREF(error_traceback);
@@ -940,6 +976,11 @@ PyObject *PyC_ExceptionBuffer_Simple(void)
 
   PyErr_Fetch(&error_type, &error_value, &error_traceback);
 
+  /* Since #PyErr_Print is not called it's not essential that `SystemExit` exceptions are handled.
+   * Do this to match the behavior of #PyC_ExceptionBuffer since requesting a brief exception
+   * shouldn't result in completely different behavior. */
+  pyc_exception_buffer_handle_system_exit(error_type, error_value, error_traceback);
+
   if (PyErr_GivenExceptionMatches(error_type, PyExc_SyntaxError)) {
     /* Special exception for syntax errors,
      * in these cases the full error is verbose and not very useful,