[3.12] pythongh-126489: Do not call persistent_id() for a persistent id in Python pickle (pythonGH-126490)

(cherry picked from commit 8fa4dc4)

Co-authored-by: Serhiy Storchaka <[email protected]>

Author: serhiy-storchaka

Lib/pickle.py

@@ -533,10 +533,11 @@ def save(self, obj, save_persistent_id=True):
         self.framer.commit_frame()
 
         # Check for persistent id (defined by a subclass)
-        pid = self.persistent_id(obj)
-        if pid is not None and save_persistent_id:
-            self.save_pers(pid)
-            return
+        if save_persistent_id:
+            pid = self.persistent_id(obj)
+            if pid is not None:
+                self.save_pers(pid)
+                return
 
         # Check the memo
         x = self.memo.get(id(obj))

Misc/NEWS.d/next/Library/2024-11-06-13-41-38.gh-issue-126489.toaf-0.rst

@@ -0,0 +1,3 @@
+The Python implementation of :mod:`pickle` no longer calls
+:meth:`pickle.Pickler.persistent_id` for the result of
+:meth:`!persistent_id`.