In Doc/tutorial/inputoutput.rst, the docs state this about opening a file:

 Normally, files are opened in :dfn:`text mode`, that means, you read and write
 strings from and to the file, which are encoded in a specific encoding (the
 default being UTF-8).

That statement is directly contradicted by the docs for open (Doc/library/functions.rst) which indicate:

 In text mode, if encoding is not specified the encoding used is platform
 dependent: locale.getpreferredencoding(False) is called to get the current
 locale encoding.

The implementation matches the latter indication.

corrected

Hmm.  It's a tutorial.  It would probably be better to just say "the default is platform dependent" with a link to the open docs.

@r.david.murray: just like that? (see patch v2)

A direct link to open would be better ("see :func:`~functions.open`" should do it, I think).

tried again :)

Looks good to me assuming it renders correctly.

@acucci and R. David Murray: I've run the patch locally, and all renders well except for one link.

@acucci: I believe that the direct link to the `open()` command should be

... "see :func:`open` "

An example exists at the beginning of the section containing this line. The command in the current patch renders as plain text and not a link. If you can fix this small issue, the patch should be ready to merge (pending R David Murray's agreement). Thanks!

ok, this time I tested the render myself and seems ok. For rendering I used sphinx. Sorry if I didn't try the final result in the first time, but I've never had the chance to use rst files before.

New changeset c9e78d91d588 by Alessandro Cucci in branch '3.4':
Issue #24729: Update tutorial to match implementation.
https://hg.python.org/cpython/rev/c9e78d91d588

New changeset 20084be60761 by Jason R. Coombs in branch '3.4':
Issue #24729: Correct reference to open function.
https://hg.python.org/cpython/rev/20084be60761

New changeset 575e60ed7cb8 by Jason R. Coombs in branch '3.5':
Merge with 3.4 for Issue #24729
https://hg.python.org/cpython/rev/575e60ed7cb8

New changeset 47330144debd by Jason R. Coombs in branch 'default':
Merge with 3.5 for Issue #24729
https://hg.python.org/cpython/rev/47330144debd

Thanks for working through this Alessandro. I've applied your v3 patch and added a subsequent commit 20084be60761 to correct the open reference.