Fix final 3.15 code names, warning filters and constant folding

Retain public co_name subclass owners for comparison and hashing. Match omitted warning modules against filenames through the exact final CPython helper imported with update_lib. Port final constant sequence folding order and align the string-format diagnostics exposed by canonical CI.

Assisted-by: OpenAI Codex:model identifier unavailable

Lib/_py_warnings.py

@@ -369,9 +369,15 @@ def _setoption(arg):
     if message or module:
         import re
     if message:
-        message = re.escape(message)
+        if len(message) >= 2 and message[0] == message[-1] == '/':
+            message = message[1:-1]
+        else:
+            message = re.escape(message)
     if module:
-        module = re.escape(module) + r'\z'
+        if len(module) >= 2 and module[0] == module[-1] == '/':
+            module = module[1:-1]
+        else:
+            module = re.escape(module) + r'\z'
     if lineno:
         try:
             lineno = int(lineno)
@@ -381,7 +387,23 @@ def _setoption(arg):
             raise _wm._OptionError("invalid lineno %r" % (lineno,)) from None
     else:
         lineno = 0
-    _wm.filterwarnings(action, message, category, module, lineno)
+    try:
+        _wm.filterwarnings(action, message, category, module, lineno)
+    except re.PatternError if message or module else ():
+        if message:
+            try:
+                re.compile(message)
+            except re.PatternError:
+                raise _wm._OptionError(f"invalid regular expression for "
+                                       f"message: {message!r}") from None
+        if module:
+            try:
+                re.compile(module)
+            except re.PatternError:
+                raise _wm._OptionError(f"invalid regular expression for "
+                                       f"module: {module!r}") from None
+        # Should never happen.
+        raise
 
 
 # Helper for _setoption()
@@ -449,9 +471,12 @@ def warn(message, category=None, stacklevel=1, source=None,
     # Check category argument
     if category is None:
         category = UserWarning
-    if not (isinstance(category, type) and issubclass(category, Warning)):
-        raise TypeError("category must be a Warning subclass, "
-                        "not '{:s}'".format(type(category).__name__))
+    elif not isinstance(category, type):
+        raise TypeError(f"category must be a Warning subclass, not "
+                        f"'{type(category).__name__}'")
+    elif not issubclass(category, Warning):
+        raise TypeError(f"category must be a Warning subclass, not "
+                        f"class '{category.__name__}'")
     if not isinstance(skip_file_prefixes, tuple):
         # The C version demands a tuple for implementation performance.
         raise TypeError('skip_file_prefixes must be a tuple of strs.')
@@ -495,14 +520,43 @@ def warn(message, category=None, stacklevel=1, source=None,
     )
 
 
+def _match_filename(pattern, filename, *, MS_WINDOWS=(sys.platform == 'win32')):
+    if not filename:
+        return pattern.match('<unknown>') is not None
+    if filename[0] == '<' and filename[-1] == '>':
+        return pattern.match(filename) is not None
+
+    is_py = (filename[-3:].lower() == '.py'
+             if MS_WINDOWS else
+             filename.endswith('.py'))
+    if is_py:
+        filename = filename[:-3]
+    if pattern.match(filename):  # for backward compatibility
+        return True
+    if MS_WINDOWS:
+        if not is_py and filename[-4:].lower() == '.pyw':
+            filename = filename[:-4]
+            is_py = True
+        if is_py and filename[-9:].lower() in (r'\__init__', '/__init__'):
+            filename = filename[:-9]
+        filename = filename.replace('\\', '/')
+    else:
+        if is_py and filename.endswith('/__init__'):
+            filename = filename[:-9]
+    filename = filename.replace('/', '.')
+    i = 0
+    while True:
+        if pattern.match(filename, i):
+            return True
+        i = filename.find('.', i) + 1
+        if not i:
+            return False
+
+
 def warn_explicit(message, category, filename, lineno,
                   module=None, registry=None, module_globals=None,
                   source=None):
     lineno = int(lineno)
-    if module is None:
-        module = filename or "<unknown>"
-        if module[-3:].lower() == ".py":
-            module = module[:-3] # XXX What about leading pathname?
     if isinstance(message, Warning):
         text = str(message)
         category = message.__class__
@@ -524,9 +578,11 @@ def warn_explicit(message, category, filename, lineno,
             action, msg, cat, mod, ln = item
             if ((msg is None or msg.match(text)) and
                 issubclass(category, cat) and
-                (mod is None or mod.match(module)) and
-                (ln == 0 or lineno == ln)):
-                break
+                (ln == 0 or lineno == ln) and
+                (mod is None or (_match_filename(mod, filename)
+                                 if module is None else
+                                 mod.match(module)))):
+                    break
         else:
             action = _wm.defaultaction
         # Early exit actions
@@ -564,17 +620,18 @@ def warn_explicit(message, category, filename, lineno,
     linecache.getlines(filename, module_globals)
 
     # Print message and context
-    msg = _wm.WarningMessage(message, category, filename, lineno, source=source)
+    msg = _wm.WarningMessage(message, category, filename, lineno,
+                             module=module, source=source)
     _wm._showwarnmsg(msg)
 
 
 class WarningMessage(object):
 
     _WARNING_DETAILS = ("message", "category", "filename", "lineno", "file",
-                        "line", "source")
+                        "line", "source", "module")
 
     def __init__(self, message, category, filename, lineno, file=None,
-                 line=None, source=None):
+                 line=None, source=None, module=None):
         self.message = message
         self.category = category
         self.filename = filename
@@ -582,12 +639,14 @@ class WarningMessage(object):
         self.file = file
         self.line = line
         self.source = source
+        self.module = module
         self._category_name = category.__name__ if category else None
 
     def __str__(self):
-        return ("{message : %r, category : %r, filename : %r, lineno : %s, "
-                    "line : %r}" % (self.message, self._category_name,
-                                    self.filename, self.lineno, self.line))
+        return ("{message : %r, category : %r, module : %r, "
+                "filename : %r, lineno : %s, line : %r}" % (
+                    self.message, self._category_name, self.module,
+                    self.filename, self.lineno, self.line))
 
     def __repr__(self):
         return f'<{type(self).__qualname__} {self}>'
@@ -647,8 +706,8 @@ class catch_warnings(object):
                 context = None
                 self._filters = self._module.filters
                 self._module.filters = self._filters[:]
-                self._showwarning = self._module.showwarning
                 self._showwarnmsg_impl = self._module._showwarnmsg_impl
+            self._showwarning = self._module.showwarning
             self._module._filters_mutated_lock_held()
             if self._record:
                 if _use_context:
@@ -656,9 +715,9 @@ class catch_warnings(object):
                 else:
                     log = []
                     self._module._showwarnmsg_impl = log.append
-                    # Reset showwarning() to the default implementation to make sure
-                    # that _showwarnmsg() calls _showwarnmsg_impl()
-                    self._module.showwarning = self._module._showwarning_orig
+                # Reset showwarning() to the default implementation to make sure
+                # that _showwarnmsg() calls _showwarnmsg_impl()
+                self._module.showwarning = self._module._showwarning_orig
             else:
                 log = None
         if self._filter is not None:
@@ -673,8 +732,8 @@ class catch_warnings(object):
                 self._module._warnings_context.set(self._saved_context)
             else:
                 self._module.filters = self._filters
-                self._module.showwarning = self._showwarning
                 self._module._showwarnmsg_impl = self._showwarnmsg_impl
+            self._module.showwarning = self._showwarning
             self._module._filters_mutated_lock_held()
 
 

crates/codegen/src/ir.rs

@@ -2251,14 +2251,17 @@ impl Blocks {
                 AnyInstruction::Real(Instruction::CallIntrinsic1 { func }) => {
                     match func.get(inst.arg) {
                         IntrinsicFunction1::ListToTuple => {
-                            if matches!(nextop, Some(Instruction::GetIter { .. })) {
+                            fold_constant_sequence_into_load_const(
+                                metadata,
+                                &mut self[block_idx],
+                                i,
+                            )?;
+                            if matches!(
+                                self[block_idx].instructions[i].instr.real(),
+                                Some(Instruction::CallIntrinsic1 { .. })
+                            ) && matches!(nextop, Some(Instruction::GetIter { .. }))
+                            {
                                 self[block_idx].instructions[i].set_to_nop();
-                            } else {
-                                fold_constant_intrinsic_list_to_tuple(
-                                    metadata,
-                                    &mut self[block_idx],
-                                    i,
-                                )?;
                             }
                         }
                         IntrinsicFunction1::UnaryPositive => {
@@ -2267,6 +2270,16 @@ impl Blocks {
                         _ => {}
                     }
                 }
+                AnyInstruction::Real(
+                    Instruction::ListAppend { .. } | Instruction::SetAdd { .. },
+                ) if u32::from(inst.arg) == 1
+                    && matches!(
+                        nextop,
+                        Some(Instruction::GetIter { .. } | Instruction::ContainsOp { .. })
+                    ) =>
+                {
+                    fold_constant_sequence_into_load_const(metadata, &mut self[block_idx], i)?;
+                }
                 AnyInstruction::Real(Instruction::BinaryOp { .. }) => {
                     fold_const_binop(metadata, &mut self[block_idx], i)?;
                 }
@@ -5456,20 +5469,24 @@ fn fold_tuple_of_constants(
     Ok(true)
 }
 
-fn fold_constant_intrinsic_list_to_tuple(
+fn fold_constant_sequence_into_load_const(
     metadata: &mut CodeUnitMetadata,
     block: &mut Block,
     i: usize,
 ) -> crate::InternalResult<bool> {
-    let Some(Instruction::CallIntrinsic1 { func }) = block.instructions[i].instr.real() else {
-        return Ok(false);
+    let (intrinsic, is_set) = match block.instructions[i].instr.real() {
+        Some(Instruction::CallIntrinsic1 { func })
+            if func.get(block.instructions[i].arg) == IntrinsicFunction1::ListToTuple =>
+        {
+            (true, false)
+        }
+        Some(Instruction::ListAppend { .. }) => (false, false),
+        Some(Instruction::SetAdd { .. }) => (false, true),
+        _ => return Ok(false),
     };
-    if func.get(block.instructions[i].arg) != IntrinsicFunction1::ListToTuple {
-        return Ok(false);
-    }
 
     let mut consts_found = 0usize;
-    let mut expect_append = true;
+    let mut expect_append = intrinsic;
     let mut pos = i;
     while let Some(prev) = pos.checked_sub(1) {
         pos = prev;
@@ -5478,9 +5495,12 @@ fn fold_constant_intrinsic_list_to_tuple(
             continue;
         }
 
-        if matches!(instr.instr.real(), Some(Instruction::BuildList { .. }))
-            && u32::from(instr.arg) == 0
-        {
+        let is_start = if is_set {
+            matches!(instr.instr.real(), Some(Instruction::BuildSet { .. }))
+        } else {
+            matches!(instr.instr.real(), Some(Instruction::BuildList { .. }))
+        };
+        if is_start && u32::from(instr.arg) == 0 {
             if !expect_append {
                 return Ok(false);
             }
@@ -5489,7 +5509,8 @@ fn fold_constant_intrinsic_list_to_tuple(
             elements
                 .try_reserve_exact(consts_found)
                 .map_err(|_| InternalError::MalformedControlFlowGraph)?;
-            for idx in (pos..i).rev() {
+            let end = if intrinsic { i } else { i + 1 };
+            for idx in (pos..end).rev() {
                 if matches!(block.instructions[idx].instr.real(), Some(Instruction::Nop)) {
                     continue;
                 }
@@ -5506,15 +5527,22 @@ fn fold_constant_intrinsic_list_to_tuple(
             instr_make_load_const(
                 metadata,
                 &mut block.instructions[i],
-                ConstantData::Tuple { elements },
+                if is_set {
+                    ConstantData::Frozenset { elements }
+                } else {
+                    ConstantData::Tuple { elements }
+                },
             )?;
             return Ok(true);
         }
 
         if expect_append {
-            if !matches!(instr.instr.real(), Some(Instruction::ListAppend { .. }))
-                || u32::from(instr.arg) != 1
-            {
+            let is_append = if is_set {
+                matches!(instr.instr.real(), Some(Instruction::SetAdd { .. }))
+            } else {
+                matches!(instr.instr.real(), Some(Instruction::ListAppend { .. }))
+            };
+            if !is_append || u32::from(instr.arg) != 1 {
                 return Ok(false);
             }
         } else {

crates/common/src/cformat.rs

@@ -20,6 +20,7 @@ pub enum CFormatErrorType {
     MissingModuloSign,
     UnsupportedFormatChar(CodePoint),
     IncompleteFormat,
+    StrayModulo,
     WidthTooBig,
     PrecisionTooBig,
     // Unimplemented,
@@ -39,6 +40,7 @@ impl fmt::Display for CFormatError {
         match self.typ {
             CFormatErrorType::UnmatchedKeyParentheses => write!(f, "incomplete format key"),
             CFormatErrorType::IncompleteFormat => write!(f, "incomplete format"),
+            CFormatErrorType::StrayModulo => write!(f, "stray % at position {}", self.index),
             CFormatErrorType::UnsupportedFormatChar(c) => write!(
                 f,
                 "unsupported format character '{}' ({:#x}) at index {}",
@@ -832,8 +834,20 @@ impl<S> CFormatStrOrBytes<S> {
 
                     let spec =
                         CFormatSpecKeyed::parse(iter, context).map_err(|err| CFormatError {
-                            typ: err.0,
-                            index: err.1,
+                            typ: if context == CFormatContext::Str
+                                && err.0 == CFormatErrorType::IncompleteFormat
+                            {
+                                CFormatErrorType::StrayModulo
+                            } else {
+                                err.0
+                            },
+                            index: if context == CFormatContext::Str
+                                && err.0 == CFormatErrorType::IncompleteFormat
+                            {
+                                index
+                            } else {
+                                err.1
+                            },
                         })?;
 
                     parts.push((index, CFormatPart::Spec(spec)));
@@ -842,8 +856,16 @@ impl<S> CFormatStrOrBytes<S> {
                     }
                 } else {
                     return Err(CFormatError {
-                        typ: CFormatErrorType::IncompleteFormat,
-                        index: index + 1,
+                        typ: if context == CFormatContext::Str {
+                            CFormatErrorType::StrayModulo
+                        } else {
+                            CFormatErrorType::IncompleteFormat
+                        },
+                        index: if context == CFormatContext::Str {
+                            index
+                        } else {
+                            index + 1
+                        },
                     });
                 }
             } else {
@@ -991,8 +1013,8 @@ mod tests {
         assert_eq!(
             "Hello %".parse::<CFormatString>(),
             Err(CFormatError {
-                typ: CFormatErrorType::IncompleteFormat,
-                index: 7
+                typ: CFormatErrorType::StrayModulo,
+                index: 6
             })
         );
     }

crates/vm/src/builtins/code.rs

@@ -427,7 +427,6 @@ pub struct PyCode {
     #[pymember(name = "co_posonlyargcount", path = "posonlyarg_count")]
     #[pymember(name = "co_kwonlyargcount", path = "kwonlyarg_count")]
     #[pymember(name = "co_stacksize", path = "max_stackdepth")]
-    #[pymember(name = "co_name", path = "obj_name")]
     #[pymember(name = "co_qualname", path = "qualname")]
     #[pymember(name = "co_flags", path = "flags")]
     // Logical code fields are finalized by `new`. Execution may specialize or
@@ -436,6 +435,8 @@ pub struct PyCode {
     pub code: CodeObject,
     /// Canonical bytes captured before execution can instrument the code.
     canonical_code: Box<[u8]>,
+    /// Preserve a public co_name subclass; exact strings use the interned owner.
+    name_owner: Option<PyStrRef>,
     /// The stable Python object exposed by co_code, allocated on first access.
     code_bytes: OnceCell<PyBytesRef>,
     /// Slot-indexed names, equivalent to CPython's `co_localsplusnames`.
@@ -578,7 +579,7 @@ impl PyCode {
             CodeField::Names => self.names_tuple.as_object(),
             CodeField::LocalsPlusNames => self.localsplus_names_tuple.as_object(),
             CodeField::LocalsPlusKinds => self.localsplus_kinds_bytes.as_object(),
-            CodeField::Name => self.code.obj_name.as_object(),
+            CodeField::Name => self.name_object(),
             CodeField::Qualname => self.code.qualname.as_object(),
             CodeField::LineTable => self.linetable_bytes.as_object(),
             CodeField::ExceptionTable => self.exceptiontable_bytes.as_object(),
@@ -661,6 +662,7 @@ impl PyCode {
             cellvars_tuple: OnceCell::new(),
             freevars_tuple: OnceCell::new(),
             canonical_code,
+            name_owner: None,
             code_bytes: OnceCell::new(),
             localsplus_names,
             source_path: AtomicPtr::new(sp),
@@ -739,6 +741,18 @@ impl PyCode {
         self.localsplus_names[index]
     }
 
+    fn name_object(&self) -> &PyObject {
+        self.name_owner
+            .as_ref()
+            .map_or_else(|| self.code.obj_name.as_object(), |name| name.as_object())
+    }
+
+    fn retain_name_subclass(&mut self, name: PyStrRef, ctx: &Context) {
+        if !name.class().is(ctx.types.str_type) {
+            self.name_owner = Some(name);
+        }
+    }
+
     pub fn source_path(&self) -> &'static PyStrInterned {
         // SAFETY: always points to a valid &'static PyStrInterned (interned strings are never deallocated)
         unsafe { &*self.source_path.load(Ordering::Relaxed) }
@@ -912,7 +926,7 @@ impl Comparable for PyCode {
             let other = class_or_notimplemented!(Self, other);
             let a = &zelf.code;
             let b = &other.code;
-            let eq = a.obj_name == b.obj_name
+            let eq = vm.bool_eq(zelf.name_object(), other.name_object())?
                 && a.arg_count == b.arg_count
                 && a.posonlyarg_count == b.posonlyarg_count
                 && a.kwonlyarg_count == b.kwonlyarg_count
@@ -951,7 +965,7 @@ impl Hashable for PyCode {
         let code = &zelf.code;
         // Hash a tuple of key attributes, matching CPython's code_hash
         let tuple = vm.ctx.new_tuple(vec![
-            vm.ctx.new_str(code.obj_name.as_str()).into(),
+            zelf.name_object().to_owned(),
             vm.ctx.new_int(code.arg_count).into(),
             vm.ctx.new_int(code.posonlyarg_count).into(),
             vm.ctx.new_int(code.kwonlyarg_count).into(),
@@ -1127,6 +1141,7 @@ impl Constructor for PyCode {
         };
 
         let mut result = Self::new(code, &vm.ctx);
+        result.retain_name_subclass(args.name, &vm.ctx);
         result.linetable_bytes = args.linetable;
         result.exceptiontable_bytes = args.exceptiontable;
         Ok(result)
@@ -1160,6 +1175,13 @@ impl Py<PyCode> {
         self.code.first_line_number.map_or(0, |n| n.get() as _)
     }
 
+    #[pygetset]
+    fn co_name(&self) -> PyStrRef {
+        self.name_owner
+            .clone()
+            .unwrap_or_else(|| self.code.obj_name.to_owned())
+    }
+
     #[pygetset]
     fn co_consts(&self) -> PyTupleRef {
         self.code
@@ -1606,7 +1628,7 @@ impl Py<PyCode> {
 
         let obj_name = match co_name {
             OptionalArg::Present(obj_name) => obj_name,
-            OptionalArg::Missing => self.code.obj_name.to_owned(),
+            OptionalArg::Missing => self.co_name(),
         };
 
         let names = match co_names {
@@ -1735,6 +1757,7 @@ impl Py<PyCode> {
         };
 
         let mut result = PyCode::new(new_code, &vm.ctx);
+        result.retain_name_subclass(obj_name, &vm.ctx);
         result.retain_normalized_names(names, None);
         result.linetable_bytes = linetable;
         result.exceptiontable_bytes = exceptiontable;

crates/vm/src/cformat.rs

@@ -203,8 +203,14 @@ fn spec_format_string(
     spec: &CFormatSpec,
     obj: PyObjectRef,
     argument: FormatArgument<'_>,
+    format_start: usize,
 ) -> PyResult<Wtf8Buf> {
     match &spec.format_type {
+        CFormatType::Unsupported { ch, .. } if ch.to_char_lossy().is_ascii_alphabetic() => Err(vm
+            .new_value_error(format!(
+                "unsupported format %{} at position {format_start}",
+                ch.to_char_lossy(),
+            ))),
         CFormatType::Unsupported { ch, index } => Err(vm.new_value_error(format!(
             "unsupported format character '{}' ({:#x}) at index {index}",
             ch.to_char_lossy(),
@@ -245,15 +251,27 @@ fn spec_format_string(
                     Ok(spec.format_number(i.as_bigint()).into())
                 } else {
                     Err(vm.new_type_error(format!(
-                        "%{} format: an integer is required, not {}",
+                        "{}: %{} requires an integer, not {}",
+                        argument.description(vm)?,
                         spec.format_type.to_char(),
-                        obj.class().name()
+                        obj.class().slot_name()
                     )))
                 }
             }
         },
         CFormatType::Float(_) => {
-            let value = ArgIntoFloat::try_from_object(vm, obj)?;
+            let value = match ArgIntoFloat::try_from_object(vm, obj.clone()) {
+                Ok(value) => value,
+                Err(error) if error.fast_isinstance(vm.ctx.exceptions.type_error) => {
+                    return Err(vm.new_type_error(format!(
+                        "{}: %{} requires a real number, not {}",
+                        argument.description(vm)?,
+                        spec.format_type.to_char(),
+                        obj.class().slot_name()
+                    )));
+                }
+                Err(error) => return Err(error),
+            };
             Ok(spec.format_float(value.into()).into())
         }
         CFormatType::Character(CCharacterType::Character) => {
@@ -504,7 +522,7 @@ pub(crate) fn cformat_string(
         }
 
         // dict
-        for (_, part) in format {
+        for (format_start, part) in format {
             match part {
                 CFormatPart::Literal(literal) => result.push_wtf8(&literal),
                 CFormatPart::Spec(CFormatSpecKeyed { mapping_key, spec }) => {
@@ -516,6 +534,7 @@ pub(crate) fn cformat_string(
                         &spec,
                         value,
                         FormatArgument::Mapping(key.as_object()),
+                        format_start,
                     )?;
                     result.push_wtf8(&part_result);
                 }
@@ -540,7 +559,7 @@ pub(crate) fn cformat_string(
     let mut value_iter = value_iter.inspect(|_| argument_index.set(argument_index.get() + 1));
     let is_tuple = values_obj.downcast_ref::<tuple::PyTuple>().is_some();
 
-    for (_, part) in format {
+    for (format_start, part) in format {
         match part {
             CFormatPart::Literal(literal) => result.push_wtf8(&literal),
             CFormatPart::Spec(CFormatSpecKeyed { mut spec, .. }) => {
@@ -561,7 +580,8 @@ pub(crate) fn cformat_string(
                 } else {
                     FormatArgument::Scalar
                 };
-                let part_result = spec_format_string(vm, &spec, value.to_owned(), argument)?;
+                let part_result =
+                    spec_format_string(vm, &spec, value.to_owned(), argument, format_start)?;
                 result.push_wtf8(&part_result);
             }
         }

crates/vm/src/warn.rs

@@ -336,22 +336,38 @@ fn update_registry(
     already_warned(registry, &altkey, true, vm)
 }
 
-fn normalize_module(filename: &Py<PyStr>, vm: &VirtualMachine) -> PyObjectRef {
-    match filename.byte_len() {
-        0 => vm.new_pyobj("<unknown>"),
-        len if len >= 3 && filename.as_bytes().ends_with(b".py") => {
-            vm.new_pyobj(&filename.as_wtf8()[..len - 3])
-        }
-        _ => filename.as_object().to_owned(),
+fn check_module_matched(
+    pattern: &PyObject,
+    module: Option<&PyObject>,
+    filename: &Py<PyStr>,
+    vm: &VirtualMachine,
+) -> PyResult<bool> {
+    if let Some(module) = module {
+        return check_matched(pattern, module, vm);
     }
+    if vm.is_none(pattern) {
+        return Ok(true);
+    }
+    if pattern.class().is(vm.ctx.types.str_type) {
+        return Ok(false);
+    }
+    let warnings = vm.import("_py_warnings", 0)?;
+    vm.call_method(
+        &warnings,
+        "_match_filename",
+        (pattern.to_owned(), filename.to_owned()),
+    )?
+    .is_true(vm)
 }
 
 /// Search a filters list for a matching action.
+#[allow(clippy::too_many_arguments)]
 fn filter_search(
     category: &PyObject,
     text: &PyObject,
     lineno: usize,
-    module: &PyObject,
+    module: Option<&PyObject>,
+    filename: &Py<PyStr>,
     filters: &PyListRef,
     list_name: &str,
     vm: &VirtualMachine,
@@ -380,7 +396,7 @@ fn filter_search(
         }
         let good_msg = check_matched(&tmp_item.as_slice()[1], text, vm)?;
         let is_subclass = category.is_subclass(&tmp_item.as_slice()[2], vm)?;
-        let good_mod = check_matched(&tmp_item.as_slice()[3], module, vm)?;
+        let good_mod = check_module_matched(&tmp_item.as_slice()[3], module, filename, vm)?;
         let ln: usize = tmp_item.as_slice()[4]
             .try_int(vm)
             .map_or(0, |v| v.as_u32_mask() as _);
@@ -397,7 +413,8 @@ fn get_filter(
     category: &PyObject,
     text: &PyObject,
     lineno: usize,
-    module: &PyObject,
+    module: Option<&PyObject>,
+    filename: &Py<PyStr>,
     vm: &VirtualMachine,
 ) -> PyResult {
     if let Some(context_filters) = get_warnings_context_filters(vm)? {
@@ -406,6 +423,7 @@ fn get_filter(
             text,
             lineno,
             module,
+            filename,
             &context_filters,
             "_warnings_context _filters",
             vm,
@@ -416,7 +434,9 @@ fn get_filter(
     }
 
     let filters = get_warnings_filters(vm)?;
-    if let Some(action) = filter_search(category, text, lineno, module, &filters, "filters", vm)? {
+    if let Some(action) = filter_search(
+        category, text, lineno, module, filename, &filters, "filters", vm,
+    )? {
         return Ok(action);
     }
     get_default_action(vm)
@@ -504,9 +524,9 @@ pub fn warn_explicit(
     source: Option<PyObjectRef>,
     vm: &VirtualMachine,
 ) -> PyResult<()> {
-    // Normalize module. None → silent return (late-shutdown safety).
-    let module = module.unwrap_or_else(|| normalize_module(&filename, vm));
-    if vm.is_none(&module) {
+    // Explicit None remains a late-shutdown silent return. An omitted module
+    // is matched against the filename by the canonical warnings helper.
+    if module.as_ref().is_some_and(|module| vm.is_none(module)) {
         return Ok(());
     }
 
@@ -543,7 +563,14 @@ pub fn warn_explicit(
     }
 
     // Get filter action
-    let action = get_filter(category.as_object(), text.as_object(), lineno, &module, vm)?;
+    let action = get_filter(
+        category.as_object(),
+        text.as_object(),
+        lineno,
+        module.as_deref(),
+        &filename,
+        vm,
+    )?;
     let action_str = PyStrRef::try_from_object(vm, action)
         .map_err(|_| vm.new_type_error("action must be a string"))?;