Issue #28162: Fixes Ctrl+Z handling in console readall()

Lib/test/test_winconsoleio.py

@@ -107,7 +107,7 @@ class WindowsConsoleIOTests(unittest.TestCase):
         source = 'ϼўТλФЙ\r\n'.encode('utf-16-le')
         expected = 'ϼўТλФЙ\r\n'.encode('utf-8')
         for read_count in range(1, 16):
-            stdin = open('CONIN$', 'rb', buffering=0)
+            with open('CONIN$', 'rb', buffering=0) as stdin:
                 write_input(stdin, source)
 
                 actual = b''
@@ -116,7 +116,6 @@ class WindowsConsoleIOTests(unittest.TestCase):
                     actual += b
 
                 self.assertEqual(actual, expected, 'stdin.read({})'.format(read_count))
-            stdin.close()
 
     def test_partial_surrogate_reads(self):
         # Test that reading less than 1 full character works when stdin
@@ -125,7 +124,7 @@ class WindowsConsoleIOTests(unittest.TestCase):
         source = '\U00101FFF\U00101001\r\n'.encode('utf-16-le')
         expected = '\U00101FFF\U00101001\r\n'.encode('utf-8')
         for read_count in range(1, 16):
-            stdin = open('CONIN$', 'rb', buffering=0)
+            with open('CONIN$', 'rb', buffering=0) as stdin:
                 write_input(stdin, source)
 
                 actual = b''
@@ -134,8 +133,15 @@ class WindowsConsoleIOTests(unittest.TestCase):
                     actual += b
 
                 self.assertEqual(actual, expected, 'stdin.read({})'.format(read_count))
-            stdin.close()
 
+    def test_ctrl_z(self):
+        with open('CONIN$', 'rb', buffering=0) as stdin:
+            source = '\xC4\x1A\r\n'.encode('utf-16-le')
+            expected = '\xC4'.encode('utf-8')
+            write_input(stdin, source)
+            a, b = stdin.read(1), stdin.readall()
+            self.assertEqual(expected[0:1], a)
+            self.assertEqual(expected[1:], b)
 
 if __name__ == "__main__":
     unittest.main()

Modules/_io/winconsoleio.c

@@ -816,19 +816,20 @@ _io__WindowsConsoleIO_readall_impl(winconsoleio *self)
 
         PyMem_Free(subbuf);
 
-        /* when the read starts with ^Z or is empty we break */
-        if (n == 0 || buf[len] == '\x1a')
+        /* when the read is empty we break */
+        if (n == 0)
             break;
 
         len += n;
     }
 
-    if (len == 0 || buf[0] == '\x1a' && _buflen(self) == 0) {
+    if (len == 0 && _buflen(self) == 0) {
         /* when the result starts with ^Z we return an empty buffer */
         PyMem_Free(buf);
         return PyBytes_FromStringAndSize(NULL, 0);
     }
 
+    if (len) {
         Py_BEGIN_ALLOW_THREADS
         bytes_size = WideCharToMultiByte(CP_UTF8, 0, buf, len,
             NULL, 0, NULL, NULL);
@@ -839,11 +840,15 @@ _io__WindowsConsoleIO_readall_impl(winconsoleio *self)
             PyMem_Free(buf);
             return PyErr_SetFromWindowsErr(err);
         }
+    } else {
+        bytes_size = 0;
+    }
 
     bytes_size += _buflen(self);
     bytes = PyBytes_FromStringAndSize(NULL, bytes_size);
     rn = _copyfrombuf(self, PyBytes_AS_STRING(bytes), bytes_size);
 
+    if (len) {
         Py_BEGIN_ALLOW_THREADS
         bytes_size = WideCharToMultiByte(CP_UTF8, 0, buf, len,
             &PyBytes_AS_STRING(bytes)[rn], bytes_size - rn, NULL, NULL);
@@ -856,6 +861,10 @@ _io__WindowsConsoleIO_readall_impl(winconsoleio *self)
             return PyErr_SetFromWindowsErr(err);
         }
 
+        /* add back the number of preserved bytes */
+        bytes_size += rn;
+    }
+
     PyMem_Free(buf);
     if (bytes_size < (size_t)PyBytes_GET_SIZE(bytes)) {
         if (_PyBytes_Resize(&bytes, n * sizeof(wchar_t)) < 0) {