[3.15] gh-79964: Clarify the imaplib fetch example in the docs (GH-152780) (GH-152859)

A FETCH response may contain additional or unsolicited data, so the
message is not always data[0][1].
(cherry picked from commit 50ae0be74988564fb09746a49eb4b8f8e740f3c3)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

diff --git a/Doc/library/imaplib.rst b/Doc/library/imaplib.rst
index b002f4978123e6d0b3509a94d0e6a6342cd2f062..cf475734636a20dad12d83eeaa470bc2c8e46848 100644 (file)
--- a/Doc/library/imaplib.rst
+++ b/Doc/library/imaplib.rst
@@ -725,3 +725,10 @@ retrieves and prints all messages::
    M.close()
    M.logout()
 
+.. note::
+
+   A ``FETCH`` response may contain additional or unsolicited data
+   (see :rfc:`3501`, section 7.4.2),
+   so production code should inspect the whole response
+   rather than rely on ``data[0][1]``.
+