Switch from mypy to ty (#465)

Redux of #418 - `ty` is still iterating, but now used over in
connect-python (connectrpc/connect-python#242); seems reasonable to be
consistent across our projects.

Author: stefanvanburen

Makefile

@@ -81,7 +81,7 @@ conformance: $(BIN)/protovalidate-conformance generate install ## Run conformanc
 lint: install $(BIN)/buf ## Lint code
 	buf format -d --exit-code
 	uv run -- ruff format --check --diff protovalidate test
-	uv run -- mypy protovalidate
+	uv run -- ty check protovalidate
 	uv run -- ruff check protovalidate test
 	uv run -- tombi format --check
 	uv run -- tombi lint

protovalidate/internal/cel_field_presence.py

@@ -33,7 +33,7 @@ def in_has() -> bool:
 
 
 class InterpretedRunner(celpy.InterpretedRunner):
-    def evaluate(self, context) -> celpy.celtypes.Value:
+    def evaluate(self, context: celpy.Context) -> celpy.celtypes.Value:
         class Evaluator(celpy.Evaluator):
             def macro_has_eval(self, exprlist) -> celpy.celtypes.BoolType:
                 _has_state.in_has = True

protovalidate/internal/rules.py

@@ -19,7 +19,7 @@
 
 import celpy
 from celpy import celtypes
-from google.protobuf import (  # type: ignore[attr-defined]
+from google.protobuf import (
     any_pb2,
     descriptor,
     duration_pb2,
@@ -33,15 +33,16 @@
 from protovalidate.internal.cel_field_presence import InterpretedRunner, in_has
 
 # protobuf 7+ removed FieldDescriptor.label / LABEL_REPEATED in favour of is_repeated.
-if hasattr(descriptor.FieldDescriptor, "is_repeated"):
+_FieldDescriptorClass = descriptor.FieldDescriptor
+if hasattr(_FieldDescriptorClass, "is_repeated"):
 
     def _is_repeated(field: descriptor.FieldDescriptor) -> bool:
-        return field.is_repeated  # type: ignore[attr-defined]
+        return field.is_repeated
 
 else:
 
     def _is_repeated(field: descriptor.FieldDescriptor) -> bool:
-        return field.label == descriptor.FieldDescriptor.LABEL_REPEATED  # type: ignore[attr-defined]
+        return field.label == descriptor.FieldDescriptor.LABEL_REPEATED
 
 
 class CompilationError(Exception):
@@ -93,14 +94,14 @@ def __init__(self, msg: message.Message):
                 continue
             self[field.name] = field_to_cel(self.msg, field)
 
-    def __getitem__(self, name):
-        field = self.desc.fields_by_name[name]
-        if field.has_presence and not self.msg.HasField(name):
+    def __getitem__(self, key):
+        field = self.desc.fields_by_name[key]
+        if field.has_presence and not self.msg.HasField(key):
             if in_has():
                 raise KeyError()
             else:
                 return _zero_value(field)
-        return super().__getitem__(name)
+        return super().__getitem__(key)
 
 
 def _msg_to_cel(msg: message.Message) -> celtypes.Value:
@@ -153,14 +154,14 @@ def _get_type_ctor(fd: typing.Any) -> typing.Callable[..., celtypes.Value] | Non
 
 def _proto_message_has_field(msg: message.Message, field: descriptor.FieldDescriptor) -> typing.Any:
     if field.is_extension:
-        return msg.HasExtension(field)  # type: ignore
+        return msg.HasExtension(field)  # ty: ignore[invalid-argument-type]
     else:
         return msg.HasField(field.name)
 
 
 def _proto_message_get_field(msg: message.Message, field: descriptor.FieldDescriptor) -> typing.Any:
     if field.is_extension:
-        return msg.Extensions[field]  # type: ignore
+        return msg.Extensions[field]  # ty: ignore[invalid-argument-type]
     else:
         return getattr(msg, field.name)
 
@@ -322,7 +323,7 @@ def sub_context(self) -> "RuleContext":
 class Rules:
     """The rules associated with a single 'rules' message."""
 
-    def validate(self, ctx: RuleContext, _: message.Message):
+    def validate(self, ctx: RuleContext, message: message.Message):  # noqa: ARG002
         """Validate the message against the rules in this rule."""
         ctx.add(Violation(rule_id="unimplemented", message="Unimplemented"))
 
@@ -440,8 +441,8 @@ def __init__(self, fields: list[descriptor.FieldDescriptor], *, required: bool):
         self._fields = fields
         self._required = required
 
-    def validate(self, ctx: RuleContext, msg: message.Message):
-        num_set_fields = sum(1 for field in self._fields if not _is_empty_field(msg, field))
+    def validate(self, ctx: RuleContext, message: message.Message):
+        num_set_fields = sum(1 for field in self._fields if not _is_empty_field(message, field))
         if num_set_fields > 1:
             ctx.add(
                 Violation(
@@ -586,8 +587,8 @@ def __init__(
             # For each set field in the message, look for the private rule
             # extension.
             for list_field, _ in rules.ListFields():
-                if validate_pb2.predefined in list_field.GetOptions().Extensions:  # type: ignore
-                    for cel in list_field.GetOptions().Extensions[validate_pb2.predefined].cel:  # type: ignore
+                if validate_pb2.predefined in list_field.GetOptions().Extensions:  # ty: ignore[unsupported-operator]
+                    for cel in list_field.GetOptions().Extensions[validate_pb2.predefined].cel:  # ty: ignore[invalid-argument-type]
                         self.add_rule(
                             env,
                             funcs,
@@ -642,11 +643,13 @@ def validate(self, ctx: RuleContext, message: message.Message):
             sub_ctx.add_field_path_element(element)
             ctx.add_errors(sub_ctx)
 
-    def validate_item(self, ctx: RuleContext, val: typing.Any, *, for_key: bool = False):
-        self._validate_value(ctx, val, for_key=for_key)
-        self._validate_cel(ctx, this_value=val, this_cel=_scalar_field_value_to_cel(val, self._field), for_key=for_key)
+    def validate_item(self, ctx: RuleContext, value: typing.Any, *, for_key: bool = False):
+        self._validate_value(ctx, value, for_key=for_key)
+        self._validate_cel(
+            ctx, this_value=value, this_cel=_scalar_field_value_to_cel(value, self._field), for_key=for_key
+        )
 
-    def _validate_value(self, ctx: RuleContext, val: typing.Any, *, for_key: bool = False):
+    def _validate_value(self, ctx: RuleContext, value: typing.Any, *, for_key: bool = False):
         pass
 
 
@@ -1079,8 +1082,8 @@ def _new_rules(self, desc: descriptor.Descriptor) -> list[Rules]:
         result: list[Rules] = []
         rule: Rules | None = None
         all_msg_oneof_fields = set()
-        if desc.GetOptions().HasExtension(validate_pb2.message):  # type: ignore
-            message_level = desc.GetOptions().Extensions[validate_pb2.message]  # type: ignore
+        if desc.GetOptions().HasExtension(validate_pb2.message):  # ty: ignore[invalid-argument-type]
+            message_level = desc.GetOptions().Extensions[validate_pb2.message]  # ty: ignore[invalid-argument-type]
             for oneof in message_level.oneof:
                 all_msg_oneof_fields.update(oneof.fields)
             if rule := self._new_message_rule(message_level, desc):

protovalidate/validator.py

@@ -84,9 +84,9 @@ def collect_violations(
                 break
         for violation in ctx.violations:
             if violation.proto.HasField("field"):
-                violation.proto.field.elements.reverse()  # type: ignore
+                violation.proto.field.elements.reverse()
             if violation.proto.HasField("rule"):
-                violation.proto.rule.elements.reverse()  # type: ignore
+                violation.proto.rule.elements.reverse()
         return ctx.violations
 
 

pyproject.toml

@@ -44,10 +44,10 @@ Source = "https://github.com/bufbuild/protovalidate-python"
 [dependency-groups]
 dev = [
   "google-re2-stubs==0.1.1",
-  "mypy==1.20.2",
   "pytest==9.0.3",
   "ruff==0.15.12",
   "tombi==0.10.5",
+  "ty==0.0.34",
   "types-protobuf==6.32.1.20260221",
 ]
 
@@ -59,9 +59,6 @@ build-backend = "hatchling.build"
 source = "vcs"
 raw-options = { fallback_version = "0.0.0" }
 
-[tool.mypy]
-mypy_path = "gen"
-
 [tool.pytest]
 # Turn all warnings into errors,
 # except DeprecationWarnings (which we knowingly tolerate due to using old `protobuf` APIs).