From 0f4f048fa5ff06438a4624bc1dc02aa458a79748 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Charles-Fran=C3=A7ois=20Natali?= <cf.natali@gmail.com>
Date: Mon, 13 Oct 2014 19:19:26 +0100
Subject: [PATCH 1/3] Issue #22435: Fix a file descriptor leak when
 SocketServer bind fails.

---
 Lib/socketserver.py           |  8 ++++++--
 Lib/test/test_socketserver.py | 10 ++++++++++
 Misc/NEWS                     |  2 ++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/Lib/socketserver.py b/Lib/socketserver.py
index 2f395fac242..73399115b6a 100644
--- a/Lib/socketserver.py
+++ b/Lib/socketserver.py
@@ -426,8 +426,12 @@ class TCPServer(BaseServer):
         self.socket = socket.socket(self.address_family,
                                     self.socket_type)
         if bind_and_activate:
-            self.server_bind()
-            self.server_activate()
+            try:
+                self.server_bind()
+                self.server_activate()
+            except:
+                self.server_close()
+                raise
 
     def server_bind(self):
         """Called by constructor to bind the socket.
diff --git a/Lib/test/test_socketserver.py b/Lib/test/test_socketserver.py
index 0617b30a69e..0276f993f97 100644
--- a/Lib/test/test_socketserver.py
+++ b/Lib/test/test_socketserver.py
@@ -302,6 +302,16 @@ class SocketServerTest(unittest.TestCase):
             t.join()
             s.server_close()
 
+    def test_tcpserver_bind_leak(self):
+        # Issue #22435: the server socket wouldn't be closed if bind()/listen()
+        # failed.
+        # Create many servers for which bind() will fail, to see if this result
+        # in FD exhaustion.
+        for i in range(1024):
+            with self.assertRaises(OverflowError):
+                socketserver.TCPServer((HOST, -1),
+                                       socketserver.StreamRequestHandler)
+
 
 def test_main():
     if imp.lock_held():
diff --git a/Misc/NEWS b/Misc/NEWS
index ab5a4cb3789..e5030cd5d81 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -27,6 +27,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #22435: Fix a file descriptor leak when SocketServer bind fails.
+
 - Issue #13096: Fixed segfault in CTypes POINTER handling of large
   values.
 

From 0373a106a1ca9ce67cd99bf0a93ab7c3abd15cb6 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <solipsis@pitrou.net>
Date: Mon, 13 Oct 2014 20:19:45 +0200
Subject: [PATCH 2/3] Issue #17636: Circular imports involving relative imports
 are now supported.

---
 .../__init__.py}                              | 42 ++++++++++++++++++-
 Lib/test/test_import/__main__.py              |  3 ++
 .../data/circular_imports/basic.py            |  2 +
 .../data/circular_imports/basic2.py           |  1 +
 .../data/circular_imports/indirect.py         |  1 +
 .../data/circular_imports/rebinding.py        |  3 ++
 .../data/circular_imports/rebinding2.py       |  3 ++
 .../data/circular_imports/subpackage.py       |  2 +
 .../circular_imports/subpkg/subpackage2.py    |  2 +
 .../data/circular_imports/subpkg/util.py      |  2 +
 .../test_import/data/circular_imports/util.py |  2 +
 Misc/NEWS                                     |  3 ++
 Python/ceval.c                                | 22 +++++++++-
 13 files changed, 85 insertions(+), 3 deletions(-)
 rename Lib/test/{test_import.py => test_import/__init__.py} (96%)
 create mode 100644 Lib/test/test_import/__main__.py
 create mode 100644 Lib/test/test_import/data/circular_imports/basic.py
 create mode 100644 Lib/test/test_import/data/circular_imports/basic2.py
 create mode 100644 Lib/test/test_import/data/circular_imports/indirect.py
 create mode 100644 Lib/test/test_import/data/circular_imports/rebinding.py
 create mode 100644 Lib/test/test_import/data/circular_imports/rebinding2.py
 create mode 100644 Lib/test/test_import/data/circular_imports/subpackage.py
 create mode 100644 Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py
 create mode 100644 Lib/test/test_import/data/circular_imports/subpkg/util.py
 create mode 100644 Lib/test/test_import/data/circular_imports/util.py

diff --git a/Lib/test/test_import.py b/Lib/test/test_import/__init__.py
similarity index 96%
rename from Lib/test/test_import.py
rename to Lib/test/test_import/__init__.py
index b4842c54b56..fd21fa29e7c 100644
--- a/Lib/test/test_import.py
+++ b/Lib/test/test_import/__init__.py
@@ -568,7 +568,7 @@ class RelativeImportTests(unittest.TestCase):
 
     def test_relimport_star(self):
         # This will import * from .test_import.
-        from . import relimport
+        from .. import relimport
         self.assertTrue(hasattr(relimport, "RelativeImportTests"))
 
     def test_issue3221(self):
@@ -1068,6 +1068,46 @@ class ImportTracebackTests(unittest.TestCase):
                                        __isolated=False)
 
 
+class CircularImportTests(unittest.TestCase):
+
+    """See the docstrings of the modules being imported for the purpose of the
+    test."""
+
+    def tearDown(self):
+        """Make sure no modules pre-exist in sys.modules which are being used to
+        test."""
+        for key in list(sys.modules.keys()):
+            if key.startswith('test.test_import.data.circular_imports'):
+                del sys.modules[key]
+
+    def test_direct(self):
+        try:
+            import test.test_import.data.circular_imports.basic
+        except ImportError:
+            self.fail('circular import through relative imports failed')
+
+    def test_indirect(self):
+        try:
+            import test.test_import.data.circular_imports.indirect
+        except ImportError:
+            self.fail('relative import in module contributing to circular '
+                      'import failed')
+
+    def test_subpackage(self):
+        try:
+            import test.test_import.data.circular_imports.subpackage
+        except ImportError:
+            self.fail('circular import involving a subpackage failed')
+
+    def test_rebinding(self):
+        try:
+            import test.test_import.data.circular_imports.rebinding as rebinding
+        except ImportError:
+            self.fail('circular import with rebinding of module attribute failed')
+        from test.test_import.data.circular_imports.subpkg import util
+        self.assertIs(util.util, rebinding.util)
+
+
 if __name__ == '__main__':
     # Test needs to be a package, so we can do relative imports.
     unittest.main()
diff --git a/Lib/test/test_import/__main__.py b/Lib/test/test_import/__main__.py
new file mode 100644
index 00000000000..ce26cbdc63b
--- /dev/null
+++ b/Lib/test/test_import/__main__.py
@@ -0,0 +1,3 @@
+import unittest
+
+unittest.main('test.test_import')
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/basic.py b/Lib/test/test_import/data/circular_imports/basic.py
new file mode 100644
index 00000000000..3e41e395dbb
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/basic.py
@@ -0,0 +1,2 @@
+"""Circular imports through direct, relative imports."""
+from . import basic2
diff --git a/Lib/test/test_import/data/circular_imports/basic2.py b/Lib/test/test_import/data/circular_imports/basic2.py
new file mode 100644
index 00000000000..00bd2f29f3b
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/basic2.py
@@ -0,0 +1 @@
+from . import basic
diff --git a/Lib/test/test_import/data/circular_imports/indirect.py b/Lib/test/test_import/data/circular_imports/indirect.py
new file mode 100644
index 00000000000..6925788d603
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/indirect.py
@@ -0,0 +1 @@
+from . import basic, basic2
diff --git a/Lib/test/test_import/data/circular_imports/rebinding.py b/Lib/test/test_import/data/circular_imports/rebinding.py
new file mode 100644
index 00000000000..f51d1c60ee0
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/rebinding.py
@@ -0,0 +1,3 @@
+"""Test the binding of names when a circular import shares the same name as an
+attribute."""
+from .rebinding2 import util
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/rebinding2.py b/Lib/test/test_import/data/circular_imports/rebinding2.py
new file mode 100644
index 00000000000..62ca7268603
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/rebinding2.py
@@ -0,0 +1,3 @@
+from .subpkg import util
+from . import rebinding
+util = util.util
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/subpackage.py b/Lib/test/test_import/data/circular_imports/subpackage.py
new file mode 100644
index 00000000000..cc36c3c3950
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/subpackage.py
@@ -0,0 +1,2 @@
+"""Circular import involving a sub-package."""
+from .subpkg import subpackage2
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py b/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py
new file mode 100644
index 00000000000..07e0bc05457
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py
@@ -0,0 +1,2 @@
+#from .util import util
+from .. import subpackage
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/subpkg/util.py b/Lib/test/test_import/data/circular_imports/subpkg/util.py
new file mode 100644
index 00000000000..f1505e9d5ad
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/subpkg/util.py
@@ -0,0 +1,2 @@
+def util():
+    pass
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/util.py b/Lib/test/test_import/data/circular_imports/util.py
new file mode 100644
index 00000000000..f1505e9d5ad
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/util.py
@@ -0,0 +1,2 @@
+def util():
+    pass
\ No newline at end of file
diff --git a/Misc/NEWS b/Misc/NEWS
index 1453637d01e..590e26e133e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@ Release date: TBA
 Core and Builtins
 -----------------
 
+- Issue #17636: Circular imports involving relative imports are now
+  supported.
+
 - Issue #22604: Fix assertion error in debug mode when dividing a complex
   number by (nan+0j).
 
diff --git a/Python/ceval.c b/Python/ceval.c
index 2dbf591d45f..4b1d6ca9697 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -4693,11 +4693,29 @@ static PyObject *
 import_from(PyObject *v, PyObject *name)
 {
     PyObject *x;
+    _Py_IDENTIFIER(__name__);
+    PyObject *fullmodname, *pkgname;
 
     x = PyObject_GetAttr(v, name);
-    if (x == NULL && PyErr_ExceptionMatches(PyExc_AttributeError)) {
+    if (x != NULL || !PyErr_ExceptionMatches(PyExc_AttributeError))
+        return x;
+    /* Issue #17636: in case this failed because of a circular relative
+       import, try to fallback on reading the module directly from
+       sys.modules. */
+    PyErr_Clear();
+    pkgname = _PyObject_GetAttrId(v, &PyId___name__);
+    if (pkgname == NULL)
+        return NULL;
+    fullmodname = PyUnicode_FromFormat("%U.%U", pkgname, name);
+    Py_DECREF(pkgname);
+    if (fullmodname == NULL)
+        return NULL;
+    x = PyDict_GetItem(PyImport_GetModuleDict(), fullmodname);
+    if (x == NULL)
         PyErr_Format(PyExc_ImportError, "cannot import name %R", name);
-    }
+    else
+        Py_INCREF(x);
+    Py_DECREF(fullmodname);
     return x;
 }
 

From 44fff77684c9088d47304ae0f844d3ac5d271a26 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <solipsis@pitrou.net>
Date: Mon, 13 Oct 2014 20:21:12 +0200
Subject: [PATCH 3/3] Whitespace

---
 Lib/test/test_import/__main__.py                                | 2 +-
 Lib/test/test_import/data/circular_imports/rebinding.py         | 2 +-
 Lib/test/test_import/data/circular_imports/rebinding2.py        | 2 +-
 Lib/test/test_import/data/circular_imports/subpackage.py        | 2 +-
 .../test_import/data/circular_imports/subpkg/subpackage2.py     | 2 +-
 Lib/test/test_import/data/circular_imports/subpkg/util.py       | 2 +-
 Lib/test/test_import/data/circular_imports/util.py              | 2 +-
 7 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/Lib/test/test_import/__main__.py b/Lib/test/test_import/__main__.py
index ce26cbdc63b..24f02a171ad 100644
--- a/Lib/test/test_import/__main__.py
+++ b/Lib/test/test_import/__main__.py
@@ -1,3 +1,3 @@
 import unittest
 
-unittest.main('test.test_import')
\ No newline at end of file
+unittest.main('test.test_import')
diff --git a/Lib/test/test_import/data/circular_imports/rebinding.py b/Lib/test/test_import/data/circular_imports/rebinding.py
index f51d1c60ee0..2b773755591 100644
--- a/Lib/test/test_import/data/circular_imports/rebinding.py
+++ b/Lib/test/test_import/data/circular_imports/rebinding.py
@@ -1,3 +1,3 @@
 """Test the binding of names when a circular import shares the same name as an
 attribute."""
-from .rebinding2 import util
\ No newline at end of file
+from .rebinding2 import util
diff --git a/Lib/test/test_import/data/circular_imports/rebinding2.py b/Lib/test/test_import/data/circular_imports/rebinding2.py
index 62ca7268603..57a9e6945d6 100644
--- a/Lib/test/test_import/data/circular_imports/rebinding2.py
+++ b/Lib/test/test_import/data/circular_imports/rebinding2.py
@@ -1,3 +1,3 @@
 from .subpkg import util
 from . import rebinding
-util = util.util
\ No newline at end of file
+util = util.util
diff --git a/Lib/test/test_import/data/circular_imports/subpackage.py b/Lib/test/test_import/data/circular_imports/subpackage.py
index cc36c3c3950..7b412f76fc7 100644
--- a/Lib/test/test_import/data/circular_imports/subpackage.py
+++ b/Lib/test/test_import/data/circular_imports/subpackage.py
@@ -1,2 +1,2 @@
 """Circular import involving a sub-package."""
-from .subpkg import subpackage2
\ No newline at end of file
+from .subpkg import subpackage2
diff --git a/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py b/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py
index 07e0bc05457..17b893a1a2f 100644
--- a/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py
+++ b/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py
@@ -1,2 +1,2 @@
 #from .util import util
-from .. import subpackage
\ No newline at end of file
+from .. import subpackage
diff --git a/Lib/test/test_import/data/circular_imports/subpkg/util.py b/Lib/test/test_import/data/circular_imports/subpkg/util.py
index f1505e9d5ad..343bd843b2e 100644
--- a/Lib/test/test_import/data/circular_imports/subpkg/util.py
+++ b/Lib/test/test_import/data/circular_imports/subpkg/util.py
@@ -1,2 +1,2 @@
 def util():
-    pass
\ No newline at end of file
+    pass
diff --git a/Lib/test/test_import/data/circular_imports/util.py b/Lib/test/test_import/data/circular_imports/util.py
index f1505e9d5ad..343bd843b2e 100644
--- a/Lib/test/test_import/data/circular_imports/util.py
+++ b/Lib/test/test_import/data/circular_imports/util.py
@@ -1,2 +1,2 @@
 def util():
-    pass
\ No newline at end of file
+    pass