Refactor warn.rs and _warnings module (RustPython#7023)

- Add already_warned() with filter version tracking
- Add type validation for _defaultaction and _onceregistry
- Use direct function names for _warnings pyattr/pyfunction
- Route stdlib::warnings::warn through warn::warn
- Remove spurious EncodingWarning from TextIOWrapper
- Clean up comments and simplify check_matched error handling
- Remove expectedFailure from 3 passing test_warnings tests

Author: youknowone

Lib/test/test_warnings/__init__.py

@@ -929,7 +929,6 @@ def test_filter(self):
             self.assertRaises(UserWarning, self.module.warn,
                                 'convert to error')
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; AttributeError: module 'warnings' has no attribute 'onceregistry'
     def test_onceregistry(self):
         # Replacing or removing the onceregistry should be okay.
         global __warningregistry__
@@ -959,7 +958,6 @@ def test_onceregistry(self):
         finally:
             self.module.onceregistry = original_registry
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; AttributeError: module 'warnings' has no attribute 'defaultaction'
     def test_default_action(self):
         # Replacing or removing defaultaction should be okay.
         message = UserWarning("defaultaction test")
@@ -1631,7 +1629,6 @@ def __del__(self):
         self.assertEqual(err.decode().rstrip(),
                          '<string>:7: UserWarning: test')
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; AssertionError: b'' doesn't start with b'<sys>:0: ResourceWarning: unclosed file '
     def test_late_resource_warning(self):
         # Issue #21925: Emitting a ResourceWarning late during the Python
         # shutdown must be logged.

crates/vm/src/stdlib/io.rs

@@ -2808,14 +2808,10 @@ mod _io {
             encoding: Option<PyUtf8StrRef>,
             vm: &VirtualMachine,
         ) -> PyResult<PyUtf8StrRef> {
-            if encoding.is_none() && vm.state.config.settings.warn_default_encoding {
-                crate::stdlib::warnings::warn(
-                    vm.ctx.exceptions.encoding_warning,
-                    "'encoding' argument not specified".to_owned(),
-                    1,
-                    vm,
-                )?;
-            }
+            // Note: Do not issue EncodingWarning here. The warning should only
+            // be issued by io.text_encoding(), the public API. This function
+            // is used internally (e.g., for stdin/stdout/stderr initialization)
+            // where no warning should be emitted.
             let encoding = match encoding {
                 None if vm.state.config.settings.utf8_mode > 0 => {
                     identifier_utf8!(vm, utf_8).to_owned()

crates/vm/src/stdlib/warnings.rs

@@ -8,13 +8,13 @@ pub fn warn(
     stack_level: usize,
     vm: &VirtualMachine,
 ) -> PyResult<()> {
-    // TODO: use rust warnings module
-    if let Ok(module) = vm.import("warnings", 0)
-        && let Ok(func) = module.get_attr("warn", vm)
-    {
-        func.call((message, category.to_owned(), stack_level), vm)?;
-    }
-    Ok(())
+    crate::warn::warn(
+        vm.new_pyobj(message),
+        Some(category.to_owned()),
+        isize::try_from(stack_level).unwrap_or(isize::MAX),
+        None,
+        vm,
+    )
 }
 
 #[pymodule]
@@ -31,18 +31,18 @@ mod _warnings {
         vm.state.warnings.filters.clone()
     }
 
-    #[pyattr(name = "_defaultaction")]
-    fn default_action(vm: &VirtualMachine) -> PyStrRef {
+    #[pyattr]
+    fn _defaultaction(vm: &VirtualMachine) -> PyStrRef {
         vm.state.warnings.default_action.clone()
     }
 
-    #[pyattr(name = "_onceregistry")]
-    fn once_registry(vm: &VirtualMachine) -> PyDictRef {
+    #[pyattr]
+    fn _onceregistry(vm: &VirtualMachine) -> PyDictRef {
         vm.state.warnings.once_registry.clone()
     }
 
-    #[pyattr(name = "_warnings_context")]
-    fn warnings_context(vm: &VirtualMachine) -> PyObjectRef {
+    #[pyattr]
+    fn _warnings_context(vm: &VirtualMachine) -> PyObjectRef {
         vm.state
             .warnings
             .context_var
@@ -63,21 +63,21 @@ mod _warnings {
             .clone()
     }
 
-    #[pyfunction(name = "_acquire_lock")]
-    fn acquire_lock(vm: &VirtualMachine) {
+    #[pyfunction]
+    fn _acquire_lock(vm: &VirtualMachine) {
         vm.state.warnings.acquire_lock();
     }
 
-    #[pyfunction(name = "_release_lock")]
-    fn release_lock(vm: &VirtualMachine) -> PyResult<()> {
+    #[pyfunction]
+    fn _release_lock(vm: &VirtualMachine) -> PyResult<()> {
         if !vm.state.warnings.release_lock() {
             return Err(vm.new_runtime_error("cannot release un-acquired lock".to_owned()));
         }
         Ok(())
     }
 
-    #[pyfunction(name = "_filters_mutated_lock_held")]
-    fn filters_mutated_lock_held(vm: &VirtualMachine) {
+    #[pyfunction]
+    fn _filters_mutated_lock_held(vm: &VirtualMachine) {
         vm.state.warnings.filters_mutated();
     }
 

crates/vm/src/vm/context.rs

@@ -247,6 +247,8 @@ declare_const_name! {
     _defaultaction,
     _onceregistry,
     _showwarnmsg,
+    defaultaction,
+    onceregistry,
     filters,
     backslashreplace,
     close,