script_bindings(python): Add ruff rule for strict typing in function (#38694)

This is part of introducing the Ruff rule [flake8-annotations
(ANN)](https://docs.astral.sh/ruff/rules/#flake8-annotations-ann) into
the script_bindings folder.

Since `codegen.py` has 10k lines of code, the strategy is to introduce
the rule first while ignoring the `ANN` Ruff rule for `codegen.py`. We
will then gradually add type annotations slice by slice to ensure no new
errors occur outside of `ANN`.

Testing: `./mach test-wpt webidl`

---------

Signed-off-by: Jerens Lensun <jerensslensun@gmail.com>

components/script_bindings/codegen/codegen.py

@@ -4,11 +4,14 @@
 
 # Common codegen classes.
 
+# fmt: off
+
 from WebIDL import IDLUnionType
 from WebIDL import IDLSequenceType
 from collections import defaultdict
 from itertools import groupby
-from typing import Generator, Optional, cast
+from typing import Optional
+from collections.abc import Generator
 from abc import abstractmethod
 
 import operator
@@ -2679,6 +2682,7 @@ def getAllTypes(
     for d in descriptors:
         for t in getTypesFromDescriptor(d):
             if t.isRecord():
+                # pyrefly: ignore  # missing-attribute
                 yield (t.inner, d)
             yield (t, d)
     for dictionary in dictionaries:
@@ -4722,7 +4726,7 @@ pub(crate) fn init_{infoName}<D: DomTypes>() {{
                 assert isAlwaysInSlot or self.member.getExtendedAttribute("Cached")
                 isLazilyCachedInSlot = not isAlwaysInSlot
                 # pyrefly: ignore  # unknown-name
-                slotIndex = memberReservedSlot(self.member)  # noqa:FIXME: memberReservedSlot is not defined
+                slotIndex = memberReservedSlot(self.member)  # noqa: F821 FIXME: memberReservedSlot is not defined
                 # We'll statically assert that this is not too big in
                 # CGUpdateMemberSlotsMethod, in the case when
                 # isAlwaysInSlot is true.

components/script_bindings/codegen/configuration.py

@@ -2,6 +2,10 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
+# fmt: off
+
+from __future__ import annotations
+
 import functools
 import os
 from typing import Any
@@ -30,7 +34,7 @@ class Configuration:
     enumConfig: dict[str, Any]
     dictConfig: dict[str, Any]
     unionConfig: dict[str, Any]
-    descriptors: list["Descriptor"]
+    descriptors: list[Descriptor]
     interfaces: dict[str, IDLInterface]
 
     def __init__(self, filename: str, parseData: list[IDLInterface]) -> None:
@@ -86,46 +90,46 @@ class Configuration:
                           c.isCallback() and not c.isInterface()]
 
         # Keep the descriptor list sorted for determinism.
-        def cmp(x, y):
+        def cmp(x: str, y: str) -> int:
             return (x > y) - (x < y)
         self.descriptors.sort(key=functools.cmp_to_key(lambda x, y: cmp(x.name, y.name)))
 
     def getInterface(self, ifname: str) -> IDLInterface:
         return self.interfaces[ifname]
 
-    def getDescriptors(self, **filters) -> list["Descriptor"]:
+    def getDescriptors(self, **filters: IDLInterface) -> list[Descriptor]:
         """Gets the descriptors that match the given filters."""
         curr = self.descriptors
         for key, val in filters.items():
             if key == 'webIDLFile':
-                def getter(x: Descriptor):
+                def getter(x: Descriptor) -> str:
                     return x.interface.location.filename
             elif key == 'hasInterfaceObject':
-                def getter(x):
+                def getter(x: Descriptor) -> bool:
                     return x.interface.hasInterfaceObject()
             elif key == 'isCallback':
-                def getter(x):
+                def getter(x: Descriptor) -> bool:
                     return x.interface.isCallback()
             elif key == 'isNamespace':
-                def getter(x):
+                def getter(x: Descriptor) -> bool:
                     return x.interface.isNamespace()
             elif key == 'isJSImplemented':
-                def getter(x):
+                def getter(x: Descriptor) -> bool:
                     return x.interface.isJSImplemented()
             elif key == 'isGlobal':
-                def getter(x):
+                def getter(x: Descriptor) -> bool:
                     return x.isGlobal()
             elif key == 'isInline':
-                def getter(x) -> bool:
+                def getter(x: Descriptor) -> bool:
                     return x.interface.getExtendedAttribute('Inline') is not None
             elif key == 'isExposedConditionally':
-                def getter(x):
+                def getter(x: Descriptor) -> bool:
                     return x.interface.isExposedConditionally()
             elif key == 'isIteratorInterface':
-                def getter(x):
+                def getter(x: Descriptor) -> bool:
                     return x.interface.isIteratorInterface()
             else:
-                def getter(x):
+                def getter(x: Descriptor) -> Any:
                     return getattr(x, key)
             curr = [x for x in curr if getter(x) == val]
         return curr
@@ -159,7 +163,7 @@ class Configuration:
     def getCallbacks(self, webIDLFile: str = "") -> list[IDLInterface]:
         return self._filterForFile(self.callbacks, webIDLFile=webIDLFile)
 
-    def getDescriptor(self, interfaceName: str) -> "Descriptor":
+    def getDescriptor(self, interfaceName: str) -> Descriptor:
         """
         Gets the appropriate descriptor for the given interface name.
         """
@@ -172,7 +176,7 @@ class Configuration:
                                         + str(len(descriptors)) + " matches")
         return descriptors[0]
 
-    def getDescriptorProvider(self) -> "DescriptorProvider":
+    def getDescriptorProvider(self) -> DescriptorProvider:
         """
         Gets a descriptor provider that can provide descriptors as needed.
         """
@@ -180,7 +184,7 @@ class Configuration:
 
 
 class NoSuchDescriptorError(TypeError):
-    def __init__(self, str) -> None:
+    def __init__(self, str: str) -> None:
         TypeError.__init__(self, str)
 
 
@@ -188,10 +192,10 @@ class DescriptorProvider:
     """
     A way of getting descriptors for interface names
     """
-    def __init__(self, config) -> None:
+    def __init__(self, config: Configuration) -> None:
         self.config = config
 
-    def getDescriptor(self, interfaceName: str) -> "Descriptor":
+    def getDescriptor(self, interfaceName: str) -> Descriptor:
         """
         Gets the appropriate descriptor for the given interface name given the
         context of the current descriptor.
@@ -199,7 +203,7 @@ class DescriptorProvider:
         return self.config.getDescriptor(interfaceName)
 
 
-def MemberIsLegacyUnforgeable(member: IDLAttribute | IDLMethod, descriptor: "Descriptor") -> bool:
+def MemberIsLegacyUnforgeable(member: IDLAttribute | IDLMethod, descriptor: Descriptor) -> bool:
     return ((member.isAttr() or member.isMethod())
             and not member.isStatic()
             and (member.isLegacyUnforgeable()
@@ -213,7 +217,7 @@ class Descriptor(DescriptorProvider):
     interface: IDLInterface
     uniqueImplementation: bool
 
-    def __init__(self, config, interface: IDLInterface, desc: dict[str, Any]) -> None:
+    def __init__(self, config: Configuration, interface: IDLInterface, desc: dict[str, Any]) -> None:
         DescriptorProvider.__init__(self, config)
         self.interface = interface
 
@@ -289,7 +293,7 @@ class Descriptor(DescriptorProvider):
                                             and any(MemberIsLegacyUnforgeable(m, self) for m in
                                                     self.interface.members))
 
-        self.operations = {
+        self.operations: dict[str, IDLMethod | None] = {
             'IndexedGetter': None,
             'IndexedSetter': None,
             'IndexedDeleter': None,
@@ -301,7 +305,7 @@ class Descriptor(DescriptorProvider):
 
         self.hasDefaultToJSON = False
 
-        def addOperation(operation: str, m) -> None:
+        def addOperation(operation: str, m: IDLMethod) -> None:
             if not self.operations[operation]:
                 self.operations[operation] = m
 
@@ -320,7 +324,7 @@ class Descriptor(DescriptorProvider):
                     if not m.isMethod():
                         continue
 
-                    def addIndexedOrNamedOperation(operation: str, m) -> None:
+                    def addIndexedOrNamedOperation(operation: str, m: IDLMethod) -> None:
                         if not self.isGlobal():
                             self.proxy = True
                         if m.isIndexed():
@@ -357,8 +361,8 @@ class Descriptor(DescriptorProvider):
         # array of extended attributes.
         self.extendedAttributes = {'all': {}, 'getterOnly': {}, 'setterOnly': {}}
 
-        def addExtendedAttribute(attribute, config) -> None:
+        def addExtendedAttribute(attribute: dict[str, Any], config: Configuration) -> None:
-            def add(key: str, members, attribute) -> None:
+            def add(key: str, members: list[str], attribute: dict[str, Any]) -> None:
                 for member in members:
                     self.extendedAttributes[key].setdefault(member, []).append(attribute)
 
@@ -405,7 +409,7 @@ class Descriptor(DescriptorProvider):
         config.maxProtoChainLength = max(config.maxProtoChainLength,
                                          len(self.prototypeChain))
 
-    def maybeGetSuperModule(self):
+    def maybeGetSuperModule(self) -> str | None:
         """
         Returns name of super module if self is part of it
         """
@@ -416,10 +420,10 @@ class Descriptor(DescriptorProvider):
             return filename
         return None
 
-    def binaryNameFor(self, name: str, isStatic: bool):
+    def binaryNameFor(self, name: str, isStatic: bool) -> str:
         return self._binaryNames.get((name, isStatic), name)
 
-    def internalNameFor(self, name: str):
+    def internalNameFor(self, name: str) -> str:
         return self._internalNames.get(name, name)
 
     def hasNamedPropertiesObject(self) -> bool:
@@ -431,8 +435,8 @@ class Descriptor(DescriptorProvider):
     def supportsNamedProperties(self) -> bool:
         return self.operations['NamedGetter'] is not None
 
-    def getExtendedAttributes(self, member, getter=False, setter=False):
+    def getExtendedAttributes(self, member: IDLMethod, getter: bool = False, setter: bool = False) -> list[str]:
-        def maybeAppendInfallibleToAttrs(attrs, throws) -> None:
+        def maybeAppendInfallibleToAttrs(attrs: list[str], throws: bool | None) -> None:
             if throws is None:
                 attrs.append("infallible")
             elif throws is True:
@@ -458,7 +462,7 @@ class Descriptor(DescriptorProvider):
         maybeAppendInfallibleToAttrs(attrs, throws)
         return attrs
 
-    def getParentName(self):
+    def getParentName(self) -> str | None:
         parent = self.interface.parent
         while parent:
             if not parent.getExtendedAttribute("Inline"):
@@ -469,30 +473,30 @@ class Descriptor(DescriptorProvider):
     def supportsIndexedProperties(self) -> bool:
         return self.operations['IndexedGetter'] is not None
 
-    def isMaybeCrossOriginObject(self):
+    def isMaybeCrossOriginObject(self) -> bool:
         # If we're isGlobal and have cross-origin members, we're a Window, and
         # that's not a cross-origin object.  The WindowProxy is.
         return self.concrete and self.interface.hasCrossOriginMembers and not self.isGlobal()
 
-    def hasDescendants(self):
+    def hasDescendants(self) -> bool:
         return (self.interface.getUserData("hasConcreteDescendant", False)
-                or self.interface.getUserData("hasProxyDescendant", False))
+                or self.interface.getUserData("hasProxyDescendant", False) or False)
 
-    def hasHTMLConstructor(self):
+    def hasHTMLConstructor(self) -> bool:
         ctor = self.interface.ctor()
-        return ctor and ctor.isHTMLConstructor()
+        return (ctor and ctor.isHTMLConstructor()) or False
 
-    def shouldHaveGetConstructorObjectMethod(self):
+    def shouldHaveGetConstructorObjectMethod(self) -> bool:
         assert self.interface.hasInterfaceObject()
         if self.interface.getExtendedAttribute("Inline"):
             return False
         return (self.interface.isCallback() or self.interface.isNamespace()
-                or self.hasDescendants() or self.hasHTMLConstructor())
+                or self.hasDescendants() or self.hasHTMLConstructor() or False)
 
-    def shouldCacheConstructor(self):
+    def shouldCacheConstructor(self) -> bool:
         return self.hasDescendants() or self.hasHTMLConstructor()
 
-    def isExposedConditionally(self):
+    def isExposedConditionally(self) -> bool:
         return self.interface.isExposedConditionally()
 
     def isGlobal(self) -> bool:
@@ -507,19 +511,19 @@ class Descriptor(DescriptorProvider):
 # Some utility methods
 
 
-def MakeNativeName(name):
+def MakeNativeName(name: str) -> str:
     return name[0].upper() + name[1:]
 
 
-def getIdlFileName(object: IDLObject):
+def getIdlFileName(object: IDLObject) -> str:
     return os.path.basename(object.location.filename).split('.webidl')[0]
 
 
-def getModuleFromObject(object: IDLObject):
+def getModuleFromObject(object: IDLObject) -> str:
     return ('crate::codegen::GenericBindings::' + getIdlFileName(object) + 'Binding')
 
 
-def getTypesFromDescriptor(descriptor: Descriptor):
+def getTypesFromDescriptor(descriptor: Descriptor) -> list[IDLType]:
     """
     Get all argument and return types for all members of the descriptor
     """
@@ -570,7 +574,7 @@ def getUnwrappedType(type: IDLType) -> IDLType:
     return type
 
 
-def iteratorNativeType(descriptor: Descriptor, infer: bool = False):
+def iteratorNativeType(descriptor: Descriptor, infer: bool = False) -> str:
     assert descriptor.interface.maplikeOrSetlikeOrIterable is not None
     iterableDecl = descriptor.interface.maplikeOrSetlikeOrIterable
     assert (iterableDecl.isIterable() and iterableDecl.isPairIterator()) \

components/script_bindings/codegen/run.py

@@ -2,16 +2,25 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
+# fmt: off
+
+from __future__ import annotations
+
 import os
 import sys
 import json
 import re
+from typing import TYPE_CHECKING
+from collections.abc import Iterator
 
 SCRIPT_PATH = os.path.abspath(os.path.dirname(__file__))
 SERVO_ROOT = os.path.abspath(os.path.join(SCRIPT_PATH, "..", "..", ".."))
 
 FILTER_PATTERN = re.compile("// skip-unless ([A-Z_]+)\n")
 
+if TYPE_CHECKING:
+    from configuration import Configuration
+    from WebIDL import Parser
 
 def main() -> None:
     os.chdir(os.path.join(os.path.dirname(__file__)))
@@ -84,13 +93,13 @@ def main() -> None:
                 f.write(module.encode("utf-8"))
 
 
-def make_dir(path: str):
+def make_dir(path: str)-> str:
     if not os.path.exists(path):
         os.makedirs(path)
     return path
 
 
-def generate(config, name: str, filename: str) -> None:
+def generate(config: Configuration, name: str, filename: str) -> None:
     from codegen import GlobalGenRoots
     root = getattr(GlobalGenRoots, name)(config)
     code = root.define()
@@ -98,7 +107,7 @@ def generate(config, name: str, filename: str) -> None:
         f.write(code.encode("utf-8"))
 
 
-def add_css_properties_attributes(css_properties_json: str, parser) -> None:
+def add_css_properties_attributes(css_properties_json: str, parser: Parser) -> None:
     def map_preference_name(preference_name: str) -> str:
         """Map between Stylo preference names and Servo preference names as the
         `css-properties.json` file is generated by Stylo. This should be kept in sync with the
@@ -132,7 +141,7 @@ def add_css_properties_attributes(css_properties_json: str, parser) -> None:
     parser.parse(idl, "CSSStyleDeclaration_generated.webidl")
 
 
-def attribute_names(property_name: str):
+def attribute_names(property_name: str) -> Iterator[str]:
     # https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-dashed-attribute
     if property_name != "float":
         yield property_name
@@ -149,7 +158,7 @@ def attribute_names(property_name: str):
 
 
 # https://drafts.csswg.org/cssom/#css-property-to-idl-attribute
-def camel_case(chars: str, webkit_prefixed: bool = False):
+def camel_case(chars: str, webkit_prefixed: bool = False) -> Iterator[str]:
     if webkit_prefixed:
         chars = chars[1:]
     next_is_uppercase = False

pyproject.toml

@@ -8,7 +8,8 @@ extend-exclude = [
     # upstream
     "third_party/**",
     "python/mach/**",
-    "components/**",
+    "components/net/**",
+    "components/shared/**",
     "tests/**",
 ]
 
@@ -30,7 +31,8 @@ ignore = [
 ]
 
 [tool.ruff.lint.per-file-ignores]
-"!python/**/**.py" = ["ANN"]
+"etc/**" = ["ANN"]
+"components/script_bindings/codegen/codegen.py" = ["ANN"]
 "**/test.py" = ["ANN"]
 "**/*_tests.py" = ["ANN"]
 "**/tests/**/*.py" = ["ANN"]