diff options
Diffstat (limited to 'Doc/whatsnew/3.7.rst')
| -rw-r--r-- | Doc/whatsnew/3.7.rst | 42 |
1 files changed, 34 insertions, 8 deletions
diff --git a/Doc/whatsnew/3.7.rst b/Doc/whatsnew/3.7.rst index 3487662..58bfaef 100644 --- a/Doc/whatsnew/3.7.rst +++ b/Doc/whatsnew/3.7.rst @@ -188,14 +188,11 @@ resolution on Linux and Windows. New Development Mode: -X dev ---------------------------- -Add a new "development mode": ``-X dev`` command line option to enable debug -checks at runtime. - -In short, ``python3 -X dev ...`` behaves as ``PYTHONMALLOC=debug python3 -W -default -X faulthandler ...``, except that the PYTHONMALLOC environment -variable is not set in practice. - -See :option:`-X` ``dev`` for the details. +Add a new "development mode": :option:`-X` ``dev`` command line option and +:envvar:`PYTHONDEVMODE` environment variable to enable CPython's "development +mode", introducing additional runtime checks which are too expensive to be +enabled by default. See :option:`-X` ``dev`` documentation for the effects of +the development mode. Hash-based pycs --------------- @@ -481,6 +478,29 @@ Function :func:`~uu.encode` now accepts an optional *backtick* keyword argument. When it's true, zeros are represented by ``'`'`` instead of spaces. (Contributed by Xiang Zhang in :issue:`30103`.) +warnings +-------- + +The initialization of the default warnings filters has changed as follows: + +* warnings enabled via command line options (including those for :option:`-b` + and the new CPython-specific ``-X dev`` option) are always passed to the + warnings machinery via the ``sys.warnoptions`` attribute. +* warnings filters enabled via the command line or the environment now have the + following precedence order: + + * the ``BytesWarning`` filter for :option:`-b` (or ``-bb``) + * any filters specified with :option:`-W` + * any filters specified with :envvar:`PYTHONWARNINGS` + * any other CPython specific filters (e.g. the ``default`` filter added + for the new ``-X dev`` mode) + * any implicit filters defined directly by the warnings machinery +* in CPython debug builds, all warnings are now displayed by default (the + implicit filter list is empty) + +(Contributed by Nick Coghlan and Victor Stinner in :issue:`20361`, +:issue:`32043`, and :issue:`32230`) + xml.etree --------- @@ -854,6 +874,12 @@ Other CPython implementation changes either in embedding applications, or in CPython itself. (Contributed by Nick Coghlan and Eric Snow as part of :issue:`22257`.) +* Due to changes in the way the default warnings filters are configured, + setting ``Py_BytesWarningFlag`` to a value greater than one is no longer + sufficient to both emit ``BytesWarning`` messages and have them converted + to exceptions. Instead, the flag must be set (to cause the warnings to be + emitted in the first place), and an explicit ``error::BytesWarning`` + warnings filter added to convert them to exceptions. Documentation ============= |