commit f320be77ffb73e3b9e7fc98c37b8df3975d84b40
author Serhiy Storchaka <storchaka@gmail.com> Thu Jan 25 10:49:40 2018 +0200
committer INADA Naoki <methane@users.noreply.github.com> Thu Jan 25 17:49:40 2018 +0900
tree 552338f0200938249233fa4aa7b00add61965337
parent 2b822a0bb1de2612c85d8f75e3ce89eda2ac9f68

 bpo-32571: Avoid raising unneeded AttributeError and silencing it in C code (GH-5222)

Add two new private APIs: _PyObject_LookupAttr() and _PyObject_LookupAttrId()

Modules/_io/bufferedio.c

diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index b81abde..2b7aaaf 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -1541,7 +1541,9 @@
     }
     _bufferedreader_reset_buf(self);
 
-    readall = _PyObject_GetAttrWithoutError(self->raw, _PyIO_str_readall);
+    if (_PyObject_LookupAttr(self->raw, _PyIO_str_readall, &readall) < 0) {
+        goto cleanup;
+    }
     if (readall) {
         tmp = _PyObject_CallNoArg(readall);
         Py_DECREF(readall);
@@ -1561,9 +1563,6 @@
         }
         goto cleanup;
     }
-    else if (PyErr_Occurred()) {
-        goto cleanup;
-    }
 
     chunks = PyList_New(0);
     if (chunks == NULL)