Fix parsing of bracketed then called context managers (GH-5404)

Require the bracketed multiple context managers to be followed by a
colon, so that the bracketed called context manager is identified as
regular parentheses in old-style syntax.

Fixes https://github.com/cython/cython/issues/5403

2 files changed, 24 insertions, 0 deletions

diff --git a/Cython/Compiler/Parsing.py b/Cython/Compiler/Parsing.py
index 7c7b7f8a8..a796c865a 100644
--- a/Cython/Compiler/Parsing.py
+++ b/Cython/Compiler/Parsing.py
@@ -2141,6 +2141,10 @@ def p_with_items(s, is_async=False):
             s.next()
             items = p_with_items_list(s, is_async)
             s.expect(")")
+            if s.sy != ":":
+                # Fail - the message doesn't matter because we'll try the
+                # non-bracket version so it'll never be shown
+                s.error("")
         brackets_succeeded = not errors
     if not brackets_succeeded:
         # try the non-bracket version
diff --git a/tests/run/withstat_py.py b/tests/run/withstat_py.py
index 53197dc04..3cc327fb2 100644
--- a/tests/run/withstat_py.py
+++ b/tests/run/withstat_py.py
@@ -205,3 +205,23 @@ def manager_from_expression():
     g = GetManager()
     with g.get(2) as x:
         print(x)
+
+def manager_from_ternary(use_first):
+    """
+    >>> manager_from_ternary(True)
+    enter
+    exit <type 'type'> <type 'ValueError'> <type 'traceback'>
+    >>> manager_from_ternary(False)
+    enter
+    exit <type 'type'> <type 'ValueError'> <type 'traceback'>
+    In except
+    """
+    # This is mostly testing a parsing problem, hence the
+    # result of the ternary must be callable
+    cm1_getter = lambda: ContextManager("1", exit_ret=True)
+    cm2_getter = lambda: ContextManager("2")
+    try:
+        with (cm1_getter if use_first else cm2_getter)():
+            raise ValueError
+    except ValueError:
+        print("In except")