Issue #12603: Fix pydoc.synopsis() on files with non-negative st_mtime.

1 files changed, 2 insertions, 2 deletions

diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index aa4b6d5..34b2f51 100755
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -224,8 +224,8 @@ def source_synopsis(file):
 def synopsis(filename, cache={}):
     """Get the one-line summary out of a module file."""
     mtime = os.stat(filename).st_mtime
-    lastupdate, result = cache.get(filename, (0, None))
-    if lastupdate < mtime:
+    lastupdate, result = cache.get(filename, (None, None))
+    if lastupdate is None or lastupdate < mtime:
         info = inspect.getmoduleinfo(filename)
         try:
             file = tokenize.open(filename)