#3242: fix a crash in "print", if sys.stdout is set to a custom object,
whose write() method installs another sys.stdout.
Backport of r64633
diff --git a/Lib/test/test_file.py b/Lib/test/test_file.py
index 73cb5b2..0a8114a 100644
--- a/Lib/test/test_file.py
+++ b/Lib/test/test_file.py
@@ -323,11 +323,30 @@
os.unlink(TESTFN)
+class StdoutTests(unittest.TestCase):
+
+ def test_move_stdout_on_write(self):
+ # Issue 3242: sys.stdout can be replaced (and freed) during a
+ # print statement; prevent a segfault in this case
+ save_stdout = sys.stdout
+
+ class File:
+ def write(self, data):
+ if '\n' in data:
+ sys.stdout = save_stdout
+
+ try:
+ sys.stdout = File()
+ print "some text"
+ finally:
+ sys.stdout = save_stdout
+
+
def test_main():
# Historically, these tests have been sloppy about removing TESTFN.
# So get rid of it no matter what.
try:
- run_unittest(AutoFileTests, OtherFileTests)
+ run_unittest(AutoFileTests, OtherFileTests, StdoutTests)
finally:
if os.path.exists(TESTFN):
os.unlink(TESTFN)
diff --git a/Misc/NEWS b/Misc/NEWS
index 27c12c1..4d6dd83 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@
Core and builtins
-----------------
+- Issue #3242: Fix a crash inside the print statement, if sys.stdout is
+ set to a custom object whose write() method happens to install
+ another file in sys.stdout.
+
- Issue #3100: Corrected a crash on deallocation of a subclassed weakref which
holds the last (strong) reference to its referent.
diff --git a/Python/ceval.c b/Python/ceval.c
index 06d524b..9bc147b 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1603,9 +1603,11 @@
"lost sys.stdout");
}
if (w != NULL) {
+ Py_INCREF(w);
err = PyFile_WriteString("\n", w);
if (err == 0)
PyFile_SoftSpace(w, 0);
+ Py_DECREF(w);
}
Py_XDECREF(stream);
stream = NULL;