chore(cli): add mypy strict checking (#32386)

Co-authored-by: Mason Daugherty <mason@langchain.dev>

Author: cbornet

libs/cli/langchain_cli/namespaces/migrate/generate/utils.py

@@ -24,7 +24,7 @@ class ImportExtractor(ast.NodeVisitor):
 
     def __init__(self, *, from_package: Optional[str] = None) -> None:
         """Extract all imports from the given code, optionally filtering by package."""
-        self.imports: list = []
+        self.imports: list[tuple[str, str]] = []
         self.package = from_package
 
     @override

libs/cli/langchain_cli/namespaces/migrate/main.py

@@ -4,7 +4,7 @@
 
 import rich
 import typer
-from gritql import run  # type: ignore[import]
+from gritql import run  # type: ignore[import-untyped]
 from typer import Option
 
 
@@ -68,7 +68,7 @@ def migrate(
     final_code = run.apply_pattern(
         "langchain_all_migrations()",
         args,
-        grit_dir=get_gritdir_path(),
+        grit_dir=str(get_gritdir_path()),
     )
 
     raise typer.Exit(code=final_code)

libs/cli/langchain_cli/project_template/app/server.py

@@ -6,7 +6,7 @@
 
 
 @app.get("/")
-async def redirect_root_to_docs():
+async def redirect_root_to_docs() -> RedirectResponse:
     return RedirectResponse("/docs")
 
 

libs/cli/langchain_cli/utils/events.py

@@ -48,7 +48,8 @@ def create_events(events: list[EventDict]) -> Optional[dict[str, Any]]:
 
         res = conn.getresponse()
 
-        return json.loads(res.read())
+        response_data = json.loads(res.read())
+        return response_data if isinstance(response_data, dict) else None
     except (http.client.HTTPException, OSError, json.JSONDecodeError) as exc:
         typer.echo(f"Error sending events: {exc}")
         return None

libs/cli/langchain_cli/utils/git.py

@@ -6,7 +6,7 @@
 import shutil
 from collections.abc import Sequence
 from pathlib import Path
-from typing import Optional, TypedDict
+from typing import Any, Optional, TypedDict
 
 from git import Repo
 
@@ -26,7 +26,7 @@ class DependencySource(TypedDict):
     ref: Optional[str]
     subdirectory: Optional[str]
     api_path: Optional[str]
-    event_metadata: dict
+    event_metadata: dict[str, Any]
 
 
 # use poetry dependency string format

libs/cli/pyproject.toml

@@ -29,8 +29,8 @@ langchain = "langchain_cli.cli:app"
 langchain-cli = "langchain_cli.cli:app"
 
 [dependency-groups]
-dev = ["pytest<8.0.0,>=7.4.2", "pytest-watcher<1.0.0,>=0.3.4"]
-lint = ["ruff<0.13,>=0.12.2", "mypy<2.0.0,>=1.13.0"]
+dev = ["pytest<9.0.0,>=7.4.2", "pytest-watcher<1.0.0,>=0.3.4"]
+lint = ["ruff<0.13,>=0.12.2", "mypy<1.18,>=1.17.1"]
 test = ["langchain-core", "langchain"]
 typing = ["langchain"]
 test_integration = []
@@ -82,6 +82,11 @@ pyupgrade.keep-runtime-typing = true
 "scripts/**" = [ "INP", "S",]
 
 [tool.mypy]
+plugins = ["pydantic.mypy"]
+strict = true
+enable_error_code = "deprecated"
+warn_unreachable = true
+
 exclude = [
     "langchain_cli/integration_template",
     "langchain_cli/package_template",

libs/cli/scripts/generate_migrations.py

@@ -52,7 +52,7 @@ def cli() -> None:
 def generic(
     pkg1: str,
     pkg2: str,
-    output: str,
+    output: Optional[str],
     filter_by_all: bool,  # noqa: FBT001
     format_: str,
 ) -> None:

libs/cli/tests/unit_tests/test_utils.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Any, Optional
 
 import pytest
 
@@ -16,7 +16,7 @@ def _assert_dependency_equals(
     git: Optional[str] = None,
     ref: Optional[str] = None,
     subdirectory: Optional[str] = None,
-    event_metadata: Optional[dict] = None,
+    event_metadata: Optional[dict[str, Any]] = None,
 ) -> None:
     if dep["git"] != git:
         msg = f"Expected git to be {git} but got {dep['git']}"