From: Bartosz Sławecki <bartosz@ilikepython.com>
Date: Tue, 27 Jan 2026 09:49:05 +0000 (+0100)
Subject: gh-142119: Clarify that one `contextvars.Token` can only reset once in a lifetime... 
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=487bd2dea538e36cb620dd9e0f298d731b9ede8a;p=thirdparty%2FPython%2Fcpython.git

gh-142119: Clarify that one `contextvars.Token` can only reset once in a lifetime (GH-143693)
---

diff --git a/Doc/library/contextvars.rst b/Doc/library/contextvars.rst
index 60376e730cb1..653d8b597c23 100644
--- a/Doc/library/contextvars.rst
+++ b/Doc/library/contextvars.rst
@@ -119,13 +119,15 @@ Context Variables
           # After the reset call the var has no value again, so
           # var.get() would raise a LookupError.
 
+      The same *token* cannot be used twice.
+
 
 .. class:: Token
 
    *Token* objects are returned by the :meth:`ContextVar.set` method.
    They can be passed to the :meth:`ContextVar.reset` method to revert
    the value of the variable to what it was before the corresponding
-   *set*.
+   *set*. A single token cannot reset a context variable more than once.
 
    Tokens support the :ref:`context manager protocol <context-managers>`
    to automatically reset context variables. See :meth:`ContextVar.set`.