bpo-18748: Fix _pyio.IOBase destructor (closed case) (GH-13952)

_pyio.IOBase destructor now does nothing if getting the closed
attribute fails to better mimick _io.IOBase finalizer.

1 files changed, 10 insertions, 0 deletions

diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index 43c24342ad..0b6493bc8d 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -405,6 +405,16 @@ class IOBase(metaclass=abc.ABCMeta):
 
     def __del__(self):
         """Destructor.  Calls close()."""
+        try:
+            closed = self.closed
+        except Exception:
+            # If getting closed fails, then the object is probably
+            # in an unusable state, so ignore.
+            return
+
+        if closed:
+            return
+
         if _IOBASE_EMITS_UNRAISABLE:
             self.close()
         else: