gh-149083: Use sentinel for urllib.parse._UNSPECIFIED

JelleZijlstra · JelleZijlstra · commit b6842499ddc5 · 2026-05-09T10:50:13.000-07:00
This was added in 3.15; let's use a real sentinel instead of an ad-hoc list object.
diff --git a/Lib/urllib/parse.py b/Lib/urllib/parse.py
@@ -277,7 +277,7 @@ def _hostinfo(self):
         return hostname, port
 
 
-_UNSPECIFIED = ['not specified']
+_UNSPECIFIED = sentinel("_UNSPECIFIED")
 _MISSING_AS_NONE_DEFAULT = False
 
 class _ResultBase:
diff --git a/Misc/NEWS.d/next/Library/2026-05-09-10-50-00.gh-issue-149083.56s2W-.rst b/Misc/NEWS.d/next/Library/2026-05-09-10-50-00.gh-issue-149083.56s2W-.rst
@@ -0,0 +1,2 @@
+The private ``_UNSPECIFIED`` sentinel in :mod:`urllib.parse` is now an
+instance of :class:`sentinel`.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+The private ``_UNSPECIFIED`` sentinel in :mod:`urllib.parse` is now an
	`2`	+instance of :class:`sentinel`.