Prevent pop if flashes not in session to avoid modification to session fixes #227

14 years ago · 57920a5808
1 changed files with 2 additions and 1 deletions
--- a/flask/helpers.py
+++ b/flask/helpers.py
@ -249,7 +249,8 @@ def get_flashed_messages(with_categories=False):
    """
    flashes = _request_ctx_stack.top.flashes
    if flashes is None:
-        _request_ctx_stack.top.flashes = flashes = session.pop('_flashes', [])
+        _request_ctx_stack.top.flashes = flashes = session.pop('_flashes') \
+            if '_flashes' in session else []
    if not with_categories:
        return [x[1] for x in flashes]
    return flashes