Aug 30, 2017 · Aug 30, 2017 · Sep 20, 2017 · Sep 30, 2017 · Sep 30, 2017 · Sep 9, 2018
diff --git a/Lib/tempfile.py b/Lib/tempfile.py
            _os.close(fd)
            raise

 class SpooledTemporaryFile:
 class SpooledTemporaryFile(_io.IOBase):
    """Temporary file wrapper, specialized to switch from BytesIO
    or StringIO to a real file when it exceeds a certain size or
    when a fileno is needed.
    def __iter__(self):
        return self._file.__iter__()

    def __del__(self):
        """Do nothing. Underlying file will be deleted as a consequence
        of falling out of scope, anyway, if nothing else is otherwise
        deliberately referencing it."""
        pass

    def close(self):
        self._file.close()

    def read(self, *args):
        return self._file.read(*args)

    def readable(self):
        return self._file.readable()

    def readinto(self, b):
        return self._file.readinto(b)

    def readline(self, *args):
        return self._file.readline(*args)

    def readlines(self, *args):
        return self._file.readlines(*args)

    def seek(self, *args):
        self._file.seek(*args)
        return self._file.seek(*args)

    def seekable(self):
        return self._file.seekable()

    @property
    def softspace(self):

    def truncate(self, size=None):
        if size is None:
            self._file.truncate()
 returnself._file.truncate()
        else:
            if size > self._max_size:
                self.rollover()
            self._file.truncate(size)
 returnself._file.truncate(size)

    def write(self, s):
        file = self._file
        rv = file.write(s)
        self._check(file)
        return rv

    def writable(self):
        return self._file.writable()

    def writelines(self, iterable):
        file = self._file
        rv = file.writelines(iterable)
diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py
        f = self.do_create(max_size=100, pre="a", suf=".txt")
        self.assertFalse(f._rolled)

    def test_is_iobase(self):
        # SpooledTemporaryFile should implement io.IOBase
        self.assertIsInstance(self.do_create(), io.IOBase)

    def test_iobase_interface(self):
        # SpooledTemporaryFile should implement the io.IOBase interface.
        # IOBase does not declare read(), readinto(), or write(), but
        # they should be considered part of the interface.
        iobase_abstract = {'read', 'readinto', 'write'}
        spooledtempfile_abstract = set(dir(tempfile.SpooledTemporaryFile))
        missing_attributes = iobase_abstract - spooledtempfile_abstract
        self.assertFalse(
            missing_attributes,
            'io.IOBase attributes missing from SpooledTemporaryFile'
        )

    def test_del_on_close(self):
        # A SpooledTemporaryFile is deleted when closed
        dir = tempfile.mkdtemp()
diff --git a/Misc/NEWS.d/next/Library/2017-08-30-23-14-17.bpo-26175.GOaj9y.rst b/Misc/NEWS.d/next/Library/2017-08-30-23-14-17.bpo-26175.GOaj9y.rst
 Fully implement io.IOBase interface for tempfile.SpooledTemporaryFile.
 Patch by Gary Fernie.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -626,7 +626,7 @@ def TemporaryFile(mode='w+b', buffering=-1, encoding=None,
		_os.close(fd)
		raise

		class SpooledTemporaryFile:
		class SpooledTemporaryFile(_io.IOBase):
		"""Temporary file wrapper, specialized to switch from BytesIO
		or StringIO to a real file when it exceeds a certain size or
		when a fileno is needed.
Expand DownExpand Up		@@ -685,6 +685,12 @@ def __exit__(self, exc, value, tb):
		def __iter__(self):
		return self._file.__iter__()

		def __del__(self):
Copy link ppperyJun 6, 2018• edited Loading Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. This shouldn't be added: deleting the SpooledTemporaryFile will null out the reference to the underline file, and therefor call its `__del__` Copy link Member vadmiumJun 9, 2018• edited Loading Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. I think if you inherit the default`IOBase.__del__` implementation, it will callclose and defeat any ResourceWarning that might otherwise be emitted. Perhaps it is better to make`__del__` do nothing,~~or set it to`object.__del__`~~. [Seems that last option doesn’t exist.] Copy link ContributorAuthor GFernieSep 9, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. I agree: the underlying file should not be explicitly deleted as this is not expected behaviour. I can imagine a situation where someone is deliberately holding a reference to the underlying file and they would not expect/want it to be closed until their own reference has fallen out of scope. I've changed the method to do nothing and added a docstring to reflect this. Thanks for your feedback Copy link Member pitrouOct 22, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. I agree: the underlying file should not be explicitly deleted as this is not expected behaviour The doc says: """This function operates exactly as TemporaryFile() does, except [irrelevant differences].""" And then, about TemporaryFile: """On completion of the context or destruction of the file object the temporary file will be removed from the filesystem.""" So it seems the underlying fileshould be deleted when the file object disappears. Copy link coleiferMar 23, 2019 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. The point is that`IOBase` implements a`__del__` which has some side-effects. Those side effects are not desirable here. Any underlying buffers being wrapped, e.g. the`TemporaryFile` or the`BytesIO`, will be gc'd and handled as they should. I think this implementation is correct.
		"""Do nothing. Underlying file will be deleted as a consequence
		of falling out of scope, anyway, if nothing else is otherwise
		deliberately referencing it."""
		pass

		def close(self):
		self._file.close()

Expand DownExpand Up		@@ -737,14 +743,23 @@ def newlines(self):
		def read(self, *args):
		return self._file.read(*args)

		def readable(self):
		return self._file.readable()

		def readinto(self, b):
		return self._file.readinto(b)

		def readline(self, *args):
		return self._file.readline(*args)

		def readlines(self, *args):
		return self._file.readlines(*args)

		def seek(self, *args):
		self._file.seek(*args)
		return self._file.seek(*args)

		def seekable(self):
		return self._file.seekable()

		@property
		def softspace(self):
Expand All		@@ -755,18 +770,21 @@ def tell(self):

		def truncate(self, size=None):
		if size is None:
		self._file.truncate()
		returnself._file.truncate()
		else:
Copy link Contributor thehesiodFeb 12, 2020 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. this else is not needed, PEP warning, might as well fix Copy link Member merwokFeb 13, 2020 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. It's not necessary to remove the else. It does no harm. Copy link Contributor thehesiodFeb 21, 2020 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. I never said it was necessary, just bad style as it unnecessarily increased the code depth, take my comment as an FYI Copy link danieldjewellMay 13, 2020 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Just wanted to confirm@merwok - nothing needs to be changed here for approval? Copy link Member merwokMay 13, 2020 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Right, I advise to not change the`else` line.
		if size > self._max_size:
		self.rollover()
		self._file.truncate(size)
		returnself._file.truncate(size)

		def write(self, s):
		file = self._file
		rv = file.write(s)
		self._check(file)
		return rv

		def writable(self):
		return self._file.writable()

		def writelines(self, iterable):
		file = self._file
		rv = file.writelines(iterable)
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -982,6 +982,22 @@ def test_basic(self):
		f = self.do_create(max_size=100, pre="a", suf=".txt")
		self.assertFalse(f._rolled)

		def test_is_iobase(self):
		# SpooledTemporaryFile should implement io.IOBase
		self.assertIsInstance(self.do_create(), io.IOBase)

		def test_iobase_interface(self):
Copy link Member pitrouOct 22, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Those tests are not very interesting. It would be better to test the methods operate properly. Copy link coleiferMar 23, 2019 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Itliterally delegates everything to the underlying file. The existing tests should cover the behaviors. The new behaviors are intended to flesh out the API so that`SpooledTemporaryFile`, and these tests seem to cover that.
		# SpooledTemporaryFile should implement the io.IOBase interface.
		# IOBase does not declare read(), readinto(), or write(), but
		# they should be considered part of the interface.
		iobase_abstract = {'read', 'readinto', 'write'}
		spooledtempfile_abstract = set(dir(tempfile.SpooledTemporaryFile))
		missing_attributes = iobase_abstract - spooledtempfile_abstract
		self.assertFalse(
		missing_attributes,
		'io.IOBase attributes missing from SpooledTemporaryFile'
		)

		def test_del_on_close(self):
		# A SpooledTemporaryFile is deleted when closed
		dir = tempfile.mkdtemp()
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Fully implement io.IOBase interface for tempfile.SpooledTemporaryFile.
		Patch by Gary Fernie.