bpo-6532: Make the thread id an unsigned integer. (#781)

* bpo-6532: Make the thread id an unsigned integer.

From C API side the type of results of PyThread_start_new_thread() and
PyThread_get_thread_ident(), the id parameter of
PyThreadState_SetAsyncExc(), and the thread_id field of PyThreadState
changed from "long" to "unsigned long".

* Restore a check in thread_get_ident().

1 files changed, 2 insertions, 2 deletions

diff --git a/Lib/threading.py b/Lib/threading.py
index 95978d310a..929a4b0066 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -993,14 +993,14 @@ class Thread:
         #
         # Must take care to not raise an exception if _dummy_thread is being
         # used (and thus this module is being used as an instance of
-        # dummy_threading).  _dummy_thread.get_ident() always returns -1 since
+        # dummy_threading).  _dummy_thread.get_ident() always returns 1 since
         # there is only one thread if _dummy_thread is being used.  Thus
         # len(_active) is always <= 1 here, and any Thread instance created
         # overwrites the (if any) thread currently registered in _active.
         #
         # An instance of _MainThread is always created by 'threading'.  This
         # gets overwritten the instant an instance of Thread is created; both
-        # threads return -1 from _dummy_thread.get_ident() and thus have the
+        # threads return 1 from _dummy_thread.get_ident() and thus have the
         # same key in the dict.  So when the _MainThread instance created by
         # 'threading' tries to clean itself up when atexit calls this method
         # it gets a KeyError if another Thread instance was created.