sys.setrecursionlimit() now raises RecursionError

Issue #25274: sys.setrecursionlimit() now raises a RecursionError if the new
recursion limit is too low depending at the current recursion depth. Modify
also the "lower-water mark" formula to make it monotonic. This mark is used to
decide when the overflowed flag of the thread state is reset.

1 files changed, 7 insertions, 0 deletions

diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 72f5d1fd01..f6325cc8c1 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -975,6 +975,13 @@ always available.
    that supports a higher limit.  This should be done with care, because a too-high
    limit can lead to a crash.
 
+   If the new limit is too low at the current recursion depth, a
+   :exc:`RecursionError` exception is raised.
+
+   .. versionchanged:: 3.5.1
+      A :exc:`RecursionError` exception is now raised if the new limit is too
+      low at the current recursion depth.
+
 
 .. function:: setswitchinterval(interval)