diff options
| -rw-r--r-- | Doc/library/warnings.rst | 44 | ||||
| -rw-r--r-- | Lib/warnings.py | 6 | ||||
| -rw-r--r-- | Python/_warnings.c | 27 |
3 files changed, 56 insertions, 21 deletions
diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst index 67d93fa..ede991d 100644 --- a/Doc/library/warnings.rst +++ b/Doc/library/warnings.rst @@ -57,7 +57,7 @@ following warnings category classes are currently defined: | :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. | @@ -91,6 +91,9 @@ User code can define additional warning categories by subclassing one of the 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: @@ -150,14 +153,6 @@ interpreter command line. The interpreter saves the arguments for all :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: @@ -233,6 +228,37 @@ continues to increase after each operation, or else delete the previous 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 diff --git a/Lib/warnings.py b/Lib/warnings.py index 9de2c67..ec835b1 100644 --- a/Lib/warnings.py +++ b/Lib/warnings.py @@ -371,8 +371,10 @@ except ImportError: # Module initialization _processoptions(sys.warnoptions) if not _warnings_defaults: - simplefilter("ignore", category=PendingDeprecationWarning, append=1) - simplefilter("ignore", category=ImportWarning, append=1) + silence = [ImportWarning, PendingDeprecationWarning] + silence.append(DeprecationWarning) + for cls in silence: + simplefilter("ignore", category=cls) bytes_warning = sys.flags.bytes_warning if bytes_warning > 1: bytes_action = "error" diff --git a/Python/_warnings.c b/Python/_warnings.c index 55f7fda..dd7bb57 100644 --- a/Python/_warnings.c +++ b/Python/_warnings.c @@ -251,7 +251,7 @@ show_warning(PyObject *filename, int lineno, PyObject *text, PyObject 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) { @@ -846,28 +846,35 @@ create_filter(PyObject *category, const char *action) static PyObject * init_filters(void) { - PyObject *filters = PyList_New(3); + /* Don't silence DeprecationWarning if -3 was used. */ + PyObject *filters = PyList_New(4); + unsigned int pos = 0; /* Post-incremented in each use. */ + unsigned int x; const char *bytes_action; + if (filters == NULL) return NULL; - PyList_SET_ITEM(filters, 0, + PyList_SET_ITEM(filters, pos++, + create_filter(PyExc_DeprecationWarning, "ignore")); + PyList_SET_ITEM(filters, pos++, create_filter(PyExc_PendingDeprecationWarning, "ignore")); - PyList_SET_ITEM(filters, 1, create_filter(PyExc_ImportWarning, "ignore")); + PyList_SET_ITEM(filters, pos++, + 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, pos++, 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) { - Py_DECREF(filters); - return NULL; + for (x = 0; x < pos; x += 1) { + if (PyList_GET_ITEM(filters, x) == NULL) { + Py_DECREF(filters); + return NULL; + } } return filters; |