Nick Coghlan thought I should forward this to python-dev so people are aware of this change and why it occurred (plus it indirectly informs Guido I finally finished the work). ---------- Forwarded message ---------- From: brett.cannon Date: Sat, Jan 9, 2010 at 18:56 Subject: [Python-checkins] r77402 - in python/trunk: Doc/library/warnings.rst Lib/test/test_ascii_formatd.py Lib/test/test_exceptions.py Lib/warnings.py Misc/NEWS Python/_warnings.c To: python-checkins@python.org Author: brett.cannon Date: Sun Jan 10 03:56:19 2010 New Revision: 77402 Log: DeprecationWarning is now silent by default. This was originally suggested by Guido, discussed on the stdlib-sig mailing list, and given the OK by Guido directly to me. What this change essentially means is that Python has taken a policy of silencing warnings that are only of interest to developers by default. This should prevent users from seeing warnings which are triggered by an application being run against a new interpreter before the app developer has a chance to update their code. Closes issue #7319. Thanks to Antoine Pitrou, Ezio Melotti, and Brian Curtin for helping with the issue. Modified: python/trunk/Doc/library/warnings.rst python/trunk/Lib/test/test_ascii_formatd.py python/trunk/Lib/test/test_exceptions.py python/trunk/Lib/warnings.py python/trunk/Misc/NEWS python/trunk/Python/_warnings.c Modified: python/trunk/Doc/library/warnings.rst ============================================================================== --- python/trunk/Doc/library/warnings.rst (original) +++ python/trunk/Doc/library/warnings.rst Sun Jan 10 03:56:19 2010 @@ -59,7 +59,7 @@ | :exc:`UserWarning` | The default category for :func:`warn`. | +----------------------------------+-----------------------------------------------+ | :exc:`DeprecationWarning` | Base category for warnings about deprecated | -| | features. | +| | features (ignored by default). | +----------------------------------+-----------------------------------------------+ | :exc:`SyntaxWarning` | Base category for warnings about dubious | | | syntactic features. | @@ -89,6 +89,9 @@ standard warning categories. A warning category must always be a subclass of the :exc:`Warning` class. +.. versionchanged:: 2.7 + :exc:`DeprecationWarning` is ignored by default. + .. _warning-filter: @@ -148,14 +151,6 @@ :mod:`warnings` module parses these when it is first imported (invalid options are ignored, after printing a message to ``sys.stderr``). -The warnings that are ignored by default may be enabled by passing :option:`-Wd` -to the interpreter. This enables default handling for all warnings, including -those that are normally ignored by default. This is particular useful for -enabling ImportWarning when debugging problems importing a developed package. -ImportWarning can also be enabled explicitly in Python code using:: - - warnings.simplefilter('default', ImportWarning) - .. _warning-suppress: @@ -226,6 +221,37 @@ entries from the warnings list before each new operation). +Updating Code For New Versions of Python +---------------------------------------- + +Warnings that are only of interest to the developer are ignored by default. As +such you should make sure to test your code with typically ignored warnings +made visible. You can do this from the command-line by passing :option:`-Wd` +to the interpreter (this is shorthand for :option:`-W default`). This enables +default handling for all warnings, including those that are ignored by default. +To change what action is taken for encountered warnings you simply change what +argument is passed to :option:`-W`, e.g. :option:`-W error`. See the +:option:`-W` flag for more details on what is possible. + +To programmatically do the same as :option:`-Wd`, use:: + + warnings.simplefilter('default') + +Make sure to execute this code as soon as possible. This prevents the +registering of what warnings have been raised from unexpectedly influencing how +future warnings are treated. + +Having certain warnings ignored by default is done to prevent a user from +seeing warnings that are only of interest to the developer. As you do not +necessarily have control over what interpreter a user uses to run their code, +it is possible that a new version of Python will be released between your +release cycles. The new interpreter release could trigger new warnings in your +code that were not there in an older interpreter, e.g. +:exc:`DeprecationWarning` for a module that you are using. While you as a +developer want to be notified that your code is using a deprecated module, to a +user this information is essentially noise and provides no benefit to them. + + .. _warning-functions: Available Functions Modified: python/trunk/Lib/test/test_ascii_formatd.py ============================================================================== --- python/trunk/Lib/test/test_ascii_formatd.py (original) +++ python/trunk/Lib/test/test_ascii_formatd.py Sun Jan 10 03:56:19 2010 @@ -4,6 +4,7 @@ import unittest from test_support import check_warnings, run_unittest, cpython_only +import warnings class FormatDeprecationTests(unittest.TestCase): @@ -17,6 +18,7 @@ buf = create_string_buffer(' ' * 100) with check_warnings() as w: + warnings.simplefilter('default') PyOS_ascii_formatd(byref(buf), sizeof(buf), '%+.10f', c_double(10.0)) self.assertEqual(buf.value, '+10.0000000000') Modified: python/trunk/Lib/test/test_exceptions.py ============================================================================== --- python/trunk/Lib/test/test_exceptions.py (original) +++ python/trunk/Lib/test/test_exceptions.py Sun Jan 10 03:56:19 2010 @@ -309,6 +309,7 @@ # BaseException.__init__ triggers a deprecation warning. exc = BaseException("foo") with warnings.catch_warnings(record=True) as w: + warnings.simplefilter('default') self.assertEquals(exc.message, "foo") self.assertEquals(len(w), 1) self.assertEquals(w[0].category, DeprecationWarning) Modified: python/trunk/Lib/warnings.py ============================================================================== --- python/trunk/Lib/warnings.py (original) +++ python/trunk/Lib/warnings.py Sun Jan 10 03:56:19 2010 @@ -383,8 +383,8 @@ # Module initialization _processoptions(sys.warnoptions) if not _warnings_defaults: - simplefilter("ignore", category=PendingDeprecationWarning, append=1) - simplefilter("ignore", category=ImportWarning, append=1) + for cls in (DeprecationWarning, PendingDeprecationWarning, ImportWarning): + simplefilter("ignore", category=cls, append=True) bytes_warning = sys.flags.bytes_warning if bytes_warning > 1: bytes_action = "error" Modified: python/trunk/Misc/NEWS ============================================================================== --- python/trunk/Misc/NEWS (original) +++ python/trunk/Misc/NEWS Sun Jan 10 03:56:19 2010 @@ -12,6 +12,8 @@ Core and Builtins ----------------- +- Issue #7319: Silence DeprecationWarning by default. + - Issue #2335: Backport set literals syntax from Python 3.x. Library Modified: python/trunk/Python/_warnings.c ============================================================================== --- python/trunk/Python/_warnings.c (original) +++ python/trunk/Python/_warnings.c Sun Jan 10 03:56:19 2010 @@ -85,10 +85,10 @@ default_action = get_warnings_attr("defaultaction"); if (default_action == NULL) { - if (PyErr_Occurred()) { - return NULL; - } - return _default_action; + if (PyErr_Occurred()) { + return NULL; + } + return _default_action; } Py_DECREF(_default_action); @@ -202,12 +202,12 @@ mod_str = PyString_AsString(filename); if (mod_str == NULL) - return NULL; + return NULL; len = PyString_Size(filename); if (len < 0) return NULL; if (len >= 3 && - strncmp(mod_str + (len - 3), ".py", 3) == 0) { + strncmp(mod_str + (len - 3), ".py", 3) == 0) { module = PyString_FromStringAndSize(mod_str, len-3); } else { @@ -251,7 +251,7 @@ name = PyObject_GetAttrString(category, "__name__"); if (name == NULL) /* XXX Can an object lack a '__name__' attribute? */ - return; + return; f_stderr = PySys_GetObject("stderr"); if (f_stderr == NULL) { @@ -341,7 +341,7 @@ rc = already_warned(registry, key, 0); if (rc == -1) goto cleanup; - else if (rc == 1) + else if (rc == 1) goto return_none; /* Else this warning hasn't been generated before. */ } @@ -492,9 +492,9 @@ /* Setup filename. */ *filename = PyDict_GetItemString(globals, "__file__"); if (*filename != NULL) { - Py_ssize_t len = PyString_Size(*filename); + Py_ssize_t len = PyString_Size(*filename); const char *file_str = PyString_AsString(*filename); - if (file_str == NULL || (len < 0 && PyErr_Occurred())) + if (file_str == NULL || (len < 0 && PyErr_Occurred())) goto handle_error; /* if filename.lower().endswith((".pyc", ".pyo")): */ @@ -506,10 +506,10 @@ tolower(file_str[len-1]) == 'o')) { *filename = PyString_FromStringAndSize(file_str, len-1); - if (*filename == NULL) - goto handle_error; - } - else + if (*filename == NULL) + goto handle_error; + } + else Py_INCREF(*filename); } else { @@ -536,8 +536,8 @@ else { /* embedded interpreters don't have sys.argv, see bug #839151 */ *filename = PyString_FromString("__main__"); - if (*filename == NULL) - goto handle_error; + if (*filename == NULL) + goto handle_error; } } if (*filename == NULL) { @@ -839,26 +839,29 @@ static PyObject * init_filters(void) { - PyObject *filters = PyList_New(3); + PyObject *filters = PyList_New(4); const char *bytes_action; if (filters == NULL) return NULL; PyList_SET_ITEM(filters, 0, + create_filter(PyExc_DeprecationWarning, "ignore")); + PyList_SET_ITEM(filters, 1, create_filter(PyExc_PendingDeprecationWarning, "ignore")); - PyList_SET_ITEM(filters, 1, create_filter(PyExc_ImportWarning, "ignore")); + PyList_SET_ITEM(filters, 2, create_filter(PyExc_ImportWarning, "ignore")); if (Py_BytesWarningFlag > 1) bytes_action = "error"; else if (Py_BytesWarningFlag) bytes_action = "default"; else bytes_action = "ignore"; - PyList_SET_ITEM(filters, 2, create_filter(PyExc_BytesWarning, + PyList_SET_ITEM(filters, 3, create_filter(PyExc_BytesWarning, bytes_action)); if (PyList_GET_ITEM(filters, 0) == NULL || PyList_GET_ITEM(filters, 1) == NULL || - PyList_GET_ITEM(filters, 2) == NULL) { + PyList_GET_ITEM(filters, 2) == NULL || + PyList_GET_ITEM(filters, 3) == NULL) { Py_DECREF(filters); return NULL; } _______________________________________________ Python-checkins mailing list Python-checkins@python.org http://mail.python.org/mailman/listinfo/python-checkins