From 3fdd9648cb6974324ee31d81541b1dca5fb830d8 Mon Sep 17 00:00:00 2001
From: "Gregory P. Smith" <greg@mad-scientist.com>
Date: Sun, 28 Feb 2010 18:57:46 +0000
Subject: [PATCH] Merged revisions 78517 via svnmerge from
 svn+ssh://pythondev@svn.python.org/python/trunk

........
  r78517 | gregory.p.smith | 2010-02-28 10:36:09 -0800 (Sun, 28 Feb 2010) | 3 lines

  Issue #7481: When a threading.Thread failed to start it would leave the
  instance stuck in initial state and present in threading.enumerate().
........
---
 Lib/test/test_threading.py | 19 +++++++++++++++++++
 Lib/threading.py           |  7 ++++++-
 Misc/NEWS                  |  3 +++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index b8265aa9238..9e540c2275c 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -247,6 +247,25 @@ class ThreadTests(BaseTestCase):
             t.join()
         # else the thread is still running, and we have no way to kill it
 
+    def test_limbo_cleanup(self):
+        # Issue 7481: Failure to start thread should cleanup the limbo map.
+        def fail_new_thread(*args):
+            raise threading.ThreadError()
+        _start_new_thread = threading._start_new_thread
+        threading._start_new_thread = fail_new_thread
+        try:
+            t = threading.Thread(target=lambda: None)
+            try:
+                t.start()
+                assert False
+            except threading.ThreadError:
+                self.assertFalse(
+                    t in threading._limbo,
+                    "Failed to cleanup _limbo map on failure of Thread.start()."
+                )
+        finally:
+            threading._start_new_thread = _start_new_thread
+
     def test_finalize_runnning_thread(self):
         # Issue 1402: the PyGILState_Ensure / _Release functions may be called
         # very late on python exit: on deallocation of a running thread for
diff --git a/Lib/threading.py b/Lib/threading.py
index 0e77060ed59..7e513b8efe7 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -465,7 +465,12 @@ class Thread(_Verbose):
             self._note("%s.start(): starting thread", self)
         with _active_limbo_lock:
             _limbo[self] = self
-        _start_new_thread(self._bootstrap, ())
+        try:
+            _start_new_thread(self._bootstrap, ())
+        except Exception:
+            with _active_limbo_lock:
+                del _limbo[self]
+            raise
         self._started.wait()
 
     def run(self):
diff --git a/Misc/NEWS b/Misc/NEWS
index a04e068cb5e..a1f106c6adb 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -711,6 +711,9 @@ Library
 - The os.get_exec_path() function to return the list of directories that will
   be searched for an executable when launching a subprocess was added.
 
+- Issue #7481: When a threading.Thread failed to start it would leave the
+  instance stuck in initial state and present in threading.enumerate().
+
 Extension Modules
 -----------------