bpo-31285: Fix an assertion failure and a SystemError in warnings.warn_explicit. (#3219)
diff --git a/Lib/test/test_warnings/__init__.py b/Lib/test/test_warnings/__init__.py
index 2d0c46f..f27ee6e 100644
--- a/Lib/test/test_warnings/__init__.py
+++ b/Lib/test/test_warnings/__init__.py
@@ -794,6 +794,42 @@
self.assertNotIn(b'Warning!', stderr)
self.assertNotIn(b'Error', stderr)
+ def test_issue31285(self):
+ # warn_explicit() should neither raise a SystemError nor cause an
+ # assertion failure, in case the return value of get_source() has a
+ # bad splitlines() method.
+ def get_bad_loader(splitlines_ret_val):
+ class BadLoader:
+ def get_source(self, fullname):
+ class BadSource(str):
+ def splitlines(self):
+ return splitlines_ret_val
+ return BadSource('spam')
+ return BadLoader()
+
+ wmod = self.module
+ with original_warnings.catch_warnings(module=wmod):
+ wmod.filterwarnings('default', category=UserWarning)
+
+ with support.captured_stderr() as stderr:
+ wmod.warn_explicit(
+ 'foo', UserWarning, 'bar', 1,
+ module_globals={'__loader__': get_bad_loader(42),
+ '__name__': 'foobar'})
+ self.assertIn('UserWarning: foo', stderr.getvalue())
+
+ show = wmod._showwarnmsg
+ try:
+ del wmod._showwarnmsg
+ with support.captured_stderr() as stderr:
+ wmod.warn_explicit(
+ 'eggs', UserWarning, 'bar', 1,
+ module_globals={'__loader__': get_bad_loader([42]),
+ '__name__': 'foobar'})
+ self.assertIn('UserWarning: eggs', stderr.getvalue())
+ finally:
+ wmod._showwarnmsg = show
+
@support.cpython_only
def test_issue31411(self):
# warn_explicit() shouldn't raise a SystemError in case
diff --git a/Misc/NEWS.d/next/Core and Builtins/2017-08-27-21-18-30.bpo-31285.7lzaKV.rst b/Misc/NEWS.d/next/Core and Builtins/2017-08-27-21-18-30.bpo-31285.7lzaKV.rst
new file mode 100644
index 0000000..61f2c4e
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2017-08-27-21-18-30.bpo-31285.7lzaKV.rst
@@ -0,0 +1,3 @@
+Fix an assertion failure in `warnings.warn_explicit`, when the return value
+of the received loader's get_source() has a bad splitlines() method. Patch
+by Oren Milman.
diff --git a/Python/_warnings.c b/Python/_warnings.c
index f6688b0..f56e92d 100644
--- a/Python/_warnings.c
+++ b/Python/_warnings.c
@@ -893,9 +893,7 @@
}
/* Split the source into lines. */
- source_list = PyObject_CallMethodObjArgs(source,
- PyId_splitlines.object,
- NULL);
+ source_list = PyUnicode_Splitlines(source, 0);
Py_DECREF(source);
if (!source_list)
return NULL;