[Python-checkins] cpython (merge 3.4 -> default): Issue #23700: Iterator of NamedTemporaryFile now keeps a reference to

Thu Mar 19 14:25:23 CET 2015

https://hg.python.org/cpython/rev/c84a0b35999a
changeset: 95061:c84a0b35999a
parent: 95059:e18062a98a33
parent: 95060:7fa741fe9425
user: Serhiy Storchaka <storchaka at gmail.com>
date: Thu Mar 19 15:24:27 2015 +0200
summary:
 Issue #23700: Iterator of NamedTemporaryFile now keeps a reference to
NamedTemporaryFile instance. Patch by Bohuslav Kabrda.
files:
 Lib/tempfile.py | 4 +++-
 Lib/test/test_tempfile.py | 13 +++++++++++++
 Misc/NEWS | 3 +++
 3 files changed, 19 insertions(+), 1 deletions(-)

diff --git a/Lib/tempfile.py b/Lib/tempfile.py
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -426,7 +426,9 @@
 
 # iter() doesn't use __getattr__ to find the __iter__ method
 def __iter__(self):
- return iter(self.file)
+ # don't return iter(self.file), but yield from it to avoid closing
+ # file as long as it's being used as iterator, see issue #23000
+ yield from iter(self.file)
 
 
 def NamedTemporaryFile(mode='w+b', buffering=-1, encoding=None,
diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py
--- a/Lib/test/test_tempfile.py
+++ b/Lib/test/test_tempfile.py
@@ -707,6 +707,19 @@
 # No reference cycle was created.
 self.assertIsNone(wr())
 
+ def test_iter(self):
+ # Issue #23700: getting iterator from a temporary file should keep
+ # it alive as long as it's being iterated over
+ lines = [b'spam\n', b'eggs\n', b'beans\n']
+ def make_file():
+ f = tempfile.NamedTemporaryFile(mode='w+b')
+ f.write(b''.join(lines))
+ f.seek(0)
+ return f
+ for i, l in enumerate(make_file()):
+ self.assertEqual(l, lines[i])
+ self.assertEqual(i, len(lines) - 1)
+
 def test_creates_named(self):
 # NamedTemporaryFile creates files with names
 f = tempfile.NamedTemporaryFile()
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -18,6 +18,9 @@
 Library
 -------
 
+- Issue #23700: Iterator of NamedTemporaryFile now keeps a reference to
+ NamedTemporaryFile instance. Patch by Bohuslav Kabrda.
+
 - Issue #22903: The fake test case created by unittest.loader when it fails
 importing a test module is now picklable.
 
-- 
Repository URL: https://hg.python.org/cpython
