Issue #10355: SpooledTemporaryFile properties and xreadline method now work for unrolled files.

Lib/tempfile.py

@@ -546,10 +546,6 @@ class SpooledTemporaryFile:
     def closed(self):
         return self._file.closed
 
-    @property
-    def encoding(self):
-        return self._file.encoding
-
     def fileno(self):
         self.rollover()
         return self._file.fileno()
@@ -562,15 +558,17 @@ class SpooledTemporaryFile:
 
     @property
     def mode(self):
+        try:
             return self._file.mode
+        except AttributeError:
+            return self._TemporaryFileArgs[0]
 
     @property
     def name(self):
+        try:
             return self._file.name
-
-    @property
-    def newlines(self):
-        return self._file.newlines
+        except AttributeError:
+            return None
 
     def next(self):
         return self._file.next
@@ -610,4 +608,7 @@ class SpooledTemporaryFile:
         return rv
 
     def xreadlines(self, *args):
+        try:
             return self._file.xreadlines(*args)
+        except AttributeError:
+            return iter(self._file.readlines(*args))

Lib/test/test_tempfile.py

@@ -738,6 +738,17 @@ class test_SpooledTemporaryFile(TC):
         f.write(b'x')
         self.assertTrue(f._rolled)
 
+    def test_xreadlines(self):
+        f = self.do_create(max_size=20)
+        f.write(b'abc\n' * 5)
+        f.seek(0)
+        self.assertFalse(f._rolled)
+        self.assertEqual(list(f.xreadlines()), [b'abc\n'] * 5)
+        f.write(b'x\ny')
+        self.assertTrue(f._rolled)
+        f.seek(0)
+        self.assertEqual(list(f.xreadlines()), [b'abc\n'] * 5 + [b'x\n', b'y'])
+
     def test_sparse(self):
         # A SpooledTemporaryFile that is written late in the file will extend
         # when that occurs
@@ -793,6 +804,26 @@ class test_SpooledTemporaryFile(TC):
         seek(0, 0)
         self.assertTrue(read(70) == 'a'*35 + 'b'*35)
 
+    def test_properties(self):
+        f = tempfile.SpooledTemporaryFile(max_size=10)
+        f.write(b'x' * 10)
+        self.assertFalse(f._rolled)
+        self.assertEqual(f.mode, 'w+b')
+        self.assertIsNone(f.name)
+        with self.assertRaises(AttributeError):
+            f.newlines
+        with self.assertRaises(AttributeError):
+            f.encoding
+
+        f.write(b'x')
+        self.assertTrue(f._rolled)
+        self.assertEqual(f.mode, 'w+b')
+        self.assertIsNotNone(f.name)
+        with self.assertRaises(AttributeError):
+            f.newlines
+        with self.assertRaises(AttributeError):
+            f.encoding
+
     def test_context_manager_before_rollover(self):
         # A SpooledTemporaryFile can be used as a context manager
         with tempfile.SpooledTemporaryFile(max_size=1) as f:

Misc/NEWS

@@ -202,6 +202,11 @@ Core and Builtins
 Library
 -------
 
+- Issue #10355: In SpooledTemporaryFile class mode and name properties and
+  xreadlines method now work for unrolled files.  encoding and newlines
+  properties now removed as they have no sense and always produced
+  AttributeError.
+
 - Issue #16686: Fixed a lot of bugs in audioop module.  Fixed crashes in
   avgpp(), maxpp() and ratecv().  Fixed an integer overflow in add(), bias(),
   and ratecv().  reverse(), lin2lin() and ratecv() no more lose precision for