Issue #18149: Add filecmp.clear_cache() to manually clear the filecmp cache.

Patch by Mark Levitt

1 files changed, 13 insertions, 0 deletions

diff --git a/Doc/library/filecmp.rst b/Doc/library/filecmp.rst
index 95c4ddf..8471a72 100644
--- a/Doc/library/filecmp.rst
+++ b/Doc/library/filecmp.rst
@@ -27,6 +27,10 @@ The :mod:`filecmp` module defines the following functions:
    Note that no external programs are called from this function, giving it
    portability and efficiency.
 
+   This function uses a cache for past comparisons and the results,
+   with a cache invalidation mechanism relying on stale signatures
+   or by explicitly calling :func:`clear_cache`.
+
 
 .. function:: cmpfiles(dir1, dir2, common, shallow=True)
 
@@ -48,6 +52,15 @@ The :mod:`filecmp` module defines the following functions:
    one of the three returned lists.
 
 
+.. function:: clear_cache()
+
+   .. versionadded:: 3.4
+
+   Clear the filecmp cache. This may be useful if a file is compared so quickly
+   after it is modified that it is within the mtime resolution of
+   the underlying filesystem.
+
+
 .. _dircmp-objects:
 
 The :class:`dircmp` class