bpo-28528: Fix pdb.checkline() attribute error when 'curframe' is None. (#25438)

Co-authored-by: Thomas Kluyver <takowl@gmail.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/Lib/pdb.py b/Lib/pdb.py
index 98dc975..a888a0a 100755
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -752,7 +752,8 @@ class Pdb(bdb.Bdb, cmd.Cmd):
         """
         # this method should be callable before starting debugging, so default
         # to "no globals" if there is no current frame
-        globs = self.curframe.f_globals if hasattr(self, 'curframe') else None
+        frame = getattr(self, 'curframe', None)
+        globs = frame.f_globals if frame else None
         line = linecache.getline(filename, lineno, globs)
         if not line:
             self.message('End of file')