[Python-checkins] cpython (3.4): Issue #23571: Py_FatalError() now tries to flush sys.stdout and sys.stderr

Tue Mar 24 14:07:22 CET 2015

https://hg.python.org/cpython/rev/da252f12352a
changeset: 95160:da252f12352a
branch: 3.4
parent: 95153:efb2c9ac2f88
user: Victor Stinner <victor.stinner at gmail.com>
date: Tue Mar 24 13:44:35 2015 +0100
summary:
 Issue #23571: Py_FatalError() now tries to flush sys.stdout and sys.stderr
It should help to see exceptions when stderr if buffered: PyErr_Display() calls
sys.stderr.write(), it doesn't write into stderr file descriptor directly.
files:
 Python/pythonrun.c | 30 ++++++++++++++++++++++++++----
 1 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/Python/pythonrun.c b/Python/pythonrun.c
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -586,7 +586,7 @@
 _Py_Finalizing = tstate;
 initialized = 0;
 
- /* Flush stdout+stderr */
+ /* Flush sys.stdout and sys.stderr */
 flush_std_files();
 
 /* Disable signal handling */
@@ -615,7 +615,7 @@
 /* Destroy all modules */
 PyImport_Cleanup();
 
- /* Flush stdout+stderr (again, in case more was printed) */
+ /* Flush sys.stdout and sys.stderr (again, in case more was printed) */
 flush_std_files();
 
 /* Collect final garbage. This disposes of cycles created by
@@ -2596,6 +2596,7 @@
 static void
 _Py_PrintFatalError(int fd)
 {
+ PyObject *ferr, *res;
 PyObject *exception, *v, *tb;
 int has_tb;
 PyThreadState *tstate;
@@ -2606,6 +2607,13 @@
 goto display_stack;
 }
 
+ ferr = _PySys_GetObjectId(&PyId_stderr);
+ if (ferr == NULL || ferr == Py_None) {
+ /* sys.stderr is not set yet or set to None,
+ no need to try to display the exception */
+ goto display_stack;
+ }
+
 PyErr_NormalizeException(&exception, &v, &tb);
 if (tb == NULL) {
 tb = Py_None;
@@ -2613,7 +2621,7 @@
 }
 PyException_SetTraceback(v, tb);
 if (exception == NULL) {
- /* too bad, PyErr_NormalizeException() failed */
+ /* PyErr_NormalizeException() failed */
 goto display_stack;
 }
 
@@ -2622,6 +2630,14 @@
 Py_XDECREF(exception);
 Py_XDECREF(v);
 Py_XDECREF(tb);
+
+ /* sys.stderr may be buffered: call sys.stderr.flush() */
+ res = _PyObject_CallMethodId(ferr, &PyId_flush, "");
+ if (res == NULL)
+ PyErr_Clear();
+ else
+ Py_DECREF(res);
+
 if (has_tb)
 return;
 
@@ -2651,10 +2667,16 @@
 fprintf(stderr, "Fatal Python error: %s\n", msg);
 fflush(stderr); /* it helps in Windows debug build */
 
+ /* Print the exception (if an exception is set) with its traceback,
+ * or display the current Python stack. */
 _Py_PrintFatalError(fd);
 
+ /* Flush sys.stdout and sys.stderr */
+ flush_std_files();
+
 /* The main purpose of faulthandler is to display the traceback. We already
- * did our best to display it. So faulthandler can now be disabled. */
+ * did our best to display it. So faulthandler can now be disabled.
+ * (Don't trigger it on abort().) */
 _PyFaulthandler_Fini();
 
 #ifdef MS_WINDOWS
-- 
Repository URL: https://hg.python.org/cpython
