gh-121163: Add "all" as an valid alias for "always" in warnings.simplefilter() (#121164)

Add support for ``all`` as an valid alias for ``always`` in ``warnings.simplefilter()``
and ``warnings.filterswarnings()``.

Doc/library/warnings.rst

@@ -145,6 +145,8 @@ the disposition of the match.  Each entry is a tuple of the form (*action*,
   +---------------+----------------------------------------------+
   | ``"always"``  | always print matching warnings               |
   +---------------+----------------------------------------------+
+  | ``"all"``     | alias to "always"                            |
+  +---------------+----------------------------------------------+
   | ``"module"``  | print the first occurrence of matching       |
   |               | warnings for each module where the warning   |
   |               | is issued (regardless of line number)        |

Lib/test/test_warnings/__init__.py

@@ -155,40 +155,42 @@ class FilterTests(BaseTest):
             f()
             self.assertEqual(len(w), 1)
 
-    def test_always(self):
-        with original_warnings.catch_warnings(record=True,
-                module=self.module) as w:
-            self.module.resetwarnings()
-            self.module.filterwarnings("always", category=UserWarning)
-            message = "FilterTests.test_always"
-            def f():
-                self.module.warn(message, UserWarning)
-            f()
-            self.assertEqual(len(w), 1)
-            self.assertEqual(w[-1].message.args[0], message)
-            f()
-            self.assertEqual(len(w), 2)
-            self.assertEqual(w[-1].message.args[0], message)
+    def test_always_and_all(self):
+        for mode in {"always", "all"}:
+            with original_warnings.catch_warnings(record=True,
+                    module=self.module) as w:
+                self.module.resetwarnings()
+                self.module.filterwarnings(mode, category=UserWarning)
+                message = "FilterTests.test_always_and_all"
+                def f():
+                    self.module.warn(message, UserWarning)
+                f()
+                self.assertEqual(len(w), 1)
+                self.assertEqual(w[-1].message.args[0], message)
+                f()
+                self.assertEqual(len(w), 2)
+                self.assertEqual(w[-1].message.args[0], message)
 
-    def test_always_after_default(self):
-        with original_warnings.catch_warnings(record=True,
-                module=self.module) as w:
-            self.module.resetwarnings()
-            message = "FilterTests.test_always_after_ignore"
-            def f():
-                self.module.warn(message, UserWarning)
-            f()
-            self.assertEqual(len(w), 1)
-            self.assertEqual(w[-1].message.args[0], message)
-            f()
-            self.assertEqual(len(w), 1)
-            self.module.filterwarnings("always", category=UserWarning)
-            f()
-            self.assertEqual(len(w), 2)
-            self.assertEqual(w[-1].message.args[0], message)
-            f()
-            self.assertEqual(len(w), 3)
-            self.assertEqual(w[-1].message.args[0], message)
+    def test_always_and_all_after_default(self):
+        for mode in {"always", "all"}:
+            with original_warnings.catch_warnings(record=True,
+                    module=self.module) as w:
+                self.module.resetwarnings()
+                message = "FilterTests.test_always_and_all_after_ignore"
+                def f():
+                    self.module.warn(message, UserWarning)
+                f()
+                self.assertEqual(len(w), 1)
+                self.assertEqual(w[-1].message.args[0], message)
+                f()
+                self.assertEqual(len(w), 1)
+                self.module.filterwarnings(mode, category=UserWarning)
+                f()
+                self.assertEqual(len(w), 2)
+                self.assertEqual(w[-1].message.args[0], message)
+                f()
+                self.assertEqual(len(w), 3)
+                self.assertEqual(w[-1].message.args[0], message)
 
     def test_default(self):
         with original_warnings.catch_warnings(record=True,

Lib/warnings.py

@@ -132,7 +132,7 @@ def filterwarnings(action, message="", category=Warning, module="", lineno=0,
                    append=False):
     """Insert an entry into the list of warnings filters (at the front).
 
-    'action' -- one of "error", "ignore", "always", "default", "module",
+    'action' -- one of "error", "ignore", "always", "all", "default", "module",
                 or "once"
     'message' -- a regex that the warning message must match
     'category' -- a class that the warning must be a subclass of
@@ -140,7 +140,7 @@ def filterwarnings(action, message="", category=Warning, module="", lineno=0,
     'lineno' -- an integer line number, 0 matches all warnings
     'append' -- if true, append to the list of filters
     """
-    if action not in {"error", "ignore", "always", "default", "module", "once"}:
+    if action not in {"error", "ignore", "always", "all", "default", "module", "once"}:
         raise ValueError(f"invalid action: {action!r}")
     if not isinstance(message, str):
         raise TypeError("message must be a string")
@@ -171,13 +171,13 @@ def simplefilter(action, category=Warning, lineno=0, append=False):
     """Insert a simple entry into the list of warnings filters (at the front).
 
     A simple filter matches all modules and messages.
-    'action' -- one of "error", "ignore", "always", "default", "module",
+    'action' -- one of "error", "ignore", "always", "all", "default", "module",
                 or "once"
     'category' -- a class that the warning must be a subclass of
     'lineno' -- an integer line number, 0 matches all warnings
     'append' -- if true, append to the list of filters
     """
-    if action not in {"error", "ignore", "always", "default", "module", "once"}:
+    if action not in {"error", "ignore", "always", "all", "default", "module", "once"}:
         raise ValueError(f"invalid action: {action!r}")
     if not isinstance(lineno, int):
         raise TypeError("lineno must be an int")
@@ -248,8 +248,7 @@ def _setoption(arg):
 def _getaction(action):
     if not action:
         return "default"
-    if action == "all": return "always" # Alias
-    for a in ('default', 'always', 'ignore', 'module', 'once', 'error'):
+    for a in ('default', 'always', 'all', 'ignore', 'module', 'once', 'error'):
         if a.startswith(action):
             return a
     raise _OptionError("invalid action: %r" % (action,))
@@ -397,7 +396,7 @@ def warn_explicit(message, category, filename, lineno,
         if onceregistry.get(oncekey):
             return
         onceregistry[oncekey] = 1
-    elif action == "always":
+    elif action in {"always", "all"}:
         pass
     elif action == "module":
         registry[key] = 1
@@ -690,7 +689,7 @@ def _warn_unawaited_coroutine(coro):
 
 # filters contains a sequence of filter 5-tuples
 # The components of the 5-tuple are:
-# - an action: error, ignore, always, default, module, or once
+# - an action: error, ignore, always, all, default, module, or once
 # - a compiled regex that must match the warning message
 # - a class representing the warning category
 # - a compiled regex that must match the module that is being warned

Misc/NEWS.d/next/Library/2024-06-29-19-30-15.gh-issue-121163.SJKDFq.rst

@@ -0,0 +1,3 @@
+Add support for ``all`` as an valid ``action`` for :func:`warnings.simplefilter`
+and :func:`warnings.filterswarnings`.
+

Python/_warnings.c

@@ -704,9 +704,9 @@ warn_explicit(PyThreadState *tstate, PyObject *category, PyObject *message,
     }
 
     /* Store in the registry that we've been here, *except* when the action
-       is "always". */
+       is "always" or "all". */
     rc = 0;
-    if (!_PyUnicode_EqualToASCIIString(action, "always")) {
+    if (!_PyUnicode_EqualToASCIIString(action, "always") && !_PyUnicode_EqualToASCIIString(action, "all")) {
         if (registry != NULL && registry != Py_None &&
             PyDict_SetItem(registry, key, Py_True) < 0)
         {