type-checking: also use ty

ty is quite fast and also brings a performant language server

Author: yagebu

.github/workflows/test.yml

@@ -94,7 +94,7 @@ jobs:
       - run: uv run --no-dev --group pre-commit pre-commit run -a eslint
       - run: cd frontend; npx tsc
       - run: cd frontend; npx svelte-check
-  lint-python:
+  lint-python-mypy:
     runs-on: "ubuntu-latest"
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
@@ -108,3 +108,17 @@ jobs:
           enable-cache: false
       - run: touch src/fava/static/app.js
       - run: make mypy
+  lint-python-ty:
+    runs-on: "ubuntu-latest"
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
+      - uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
+        with:
+          python-version: "3.13"
+      - uses: astral-sh/setup-uv@681c641aba71e4a1c380be3ab5e12ad51f415867 # v7.1.6
+        with:
+          enable-cache: false
+      - run: touch src/fava/static/app.js
+      - run: make ty

Makefile

@@ -44,7 +44,7 @@ mostlyclean:
 
 # Run linters.
 .PHONY: lint
-lint: frontend/node_modules mypy
+lint: frontend/node_modules ty
 	uv run pre-commit run -v -a
 	cd frontend; npm exec tsc
 	cd frontend; npm exec svelte-check
@@ -54,6 +54,11 @@ lint: frontend/node_modules mypy
 mypy:
 	uv run --no-dev --group mypy mypy
 
+# Run ty for Python type-checking.
+.PHONY: ty
+ty:
+	uv run --no-dev --group ty ty check
+
 # Run tests.
 .PHONY: test test-js test-py test-py-old-deps
 test: test-js test-py

pyproject.toml

@@ -83,6 +83,14 @@ mypy = [
     "types-setuptools>=67",
     "types-simplejson>=3",
 ]
+# Type-checking with ty.
+ty = [
+    "ty>=0.0.2",
+    "pytest>=8",
+    "types-requests>=2.32.0.20250515",
+    "types-setuptools>=67",
+    "types-simplejson>=3",
+]
 # Add setuptools for the old_deps constraints
 # (otherwise it is not added to the constraints as it's only a build dependency).
 old-deps = [
@@ -108,6 +116,7 @@ dev = [
     { include-group = "mypy" },
     { include-group = "pre-commit" },
     { include-group = "test" },
+    { include-group = "ty" },
     "ruff>=0.11",
 ]
 
@@ -142,6 +151,14 @@ where = ["src"]
 line-length = 79
 preview = true
 
+[tool.ty.environment]
+python-version = "3.12"
+
+[tool.ty.src]
+exclude = [
+    "src/fava/core/ingest.py",
+]
+
 [tool.mypy]
 mypy_path = "stubs"
 strict = true

src/fava/application.py

@@ -149,7 +149,7 @@ def ledgers(self) -> list[FavaLedger]:
                 # avoid loading it already loaded while waiting for the lock
                 if self._ledgers is None:  # pragma: no cover
                     self._ledgers = self._load()
-        return self._ledgers
+        return self._ledgers  # ty:ignore[invalid-return-type]
 
     @property
     def ledgers_by_slug(self) -> dict[str, FavaLedger]:
@@ -379,7 +379,7 @@ def extension_report(extension_name: str) -> str:
         """Endpoint for extension reports."""
         ext = g.ledger.extensions.get_extension(extension_name)
         if ext is None or ext.report_title is None:
-            abort(404)
+            return abort(404)
 
         g.extension = ext
         template = ext.jinja_env.get_template(f"{ext.name}.html")
@@ -415,7 +415,7 @@ def download_journal() -> Response:
     def help_page(page_slug: str) -> str:
         """Fava's included documentation."""
         if page_slug not in HELP_PAGES:
-            abort(404)
+            return abort(404)
         help_path = Path(__file__).parent / "help" / (page_slug + ".md")
         contents = help_path.read_text(encoding="utf-8")
         html = markdown2.markdown(

src/fava/beans/create.py

@@ -48,7 +48,7 @@ def amount(amt: Amount | Decimal | str, currency: str | None = None) -> Amount:
     if isinstance(amt, str):
         return BEANCOUNT_A(amt)  # type: ignore[return-value]
     if hasattr(amt, "number") and hasattr(amt, "currency"):
-        return amt
+        return amt  # ty:ignore[invalid-return-type]
     if not isinstance(currency, str):  # pragma: no cover
         raise TypeError
     return BeancountAmount(amt, currency)  # type: ignore[return-value]

src/fava/core/__init__.py

@@ -330,46 +330,58 @@ class FavaLedger:
     #: Dict of list of all (unfiltered) entries by type.
     all_entries_by_type: EntriesByType
 
+    #: A :class:`.AccountDict` module - details about the accounts.
+    accounts: AccountDict
+
+    #: An :class:`AttributesModule` instance.
+    attributes: AttributesModule
+
+    #: A :class:`.BudgetModule` instance.
+    budgets: BudgetModule
+
+    #: A :class:`.ChartModule` instance.
+    charts: ChartModule
+
+    #: A :class:`.CommoditiesModule` instance.
+    commodities: CommoditiesModule
+
+    #: A :class:`.ExtensionModule` instance.
+    extensions: ExtensionModule
+
+    #: A :class:`.FileModule` instance.
+    file: FileModule
+
+    #: A :class:`.DecimalFormatModule` instance.
+    format_decimal: DecimalFormatModule
+
+    #: A :class:`.IngestModule` instance.
+    ingest: IngestModule
+
+    #: A :class:`.FavaMisc` instance.
+    misc: FavaMisc
+
+    #: A :class:`.QueryShell` instance.
+    query_shell: QueryShell
+
     def __init__(self, path: str, *, poll_watcher: bool = False) -> None:
         #: The path to the main Beancount file.
         self.beancount_file_path = path
         self._is_encrypted = is_encrypted_file(path)
         self.get_filtered = lru_cache(maxsize=16)(self._get_filtered)
         self.get_entry = lru_cache(maxsize=16)(self._get_entry)
 
-        #: An :class:`AttributesModule` instance.
+        self.accounts = AccountDict(self)
         self.attributes = AttributesModule(self)
-
-        #: A :class:`.BudgetModule` instance.
         self.budgets = BudgetModule(self)
-
-        #: A :class:`.ChartModule` instance.
         self.charts = ChartModule(self)
-
-        #: A :class:`.CommoditiesModule` instance.
         self.commodities = CommoditiesModule(self)
-
-        #: A :class:`.ExtensionModule` instance.
         self.extensions = ExtensionModule(self)
-
-        #: A :class:`.FileModule` instance.
         self.file = FileModule(self)
-
-        #: A :class:`.IngestModule` instance.
+        self.format_decimal = DecimalFormatModule(self)
         self.ingest = IngestModule(self)
-
-        #: A :class:`.FavaMisc` instance.
         self.misc = FavaMisc(self)
-
-        #: A :class:`.DecimalFormatModule` instance.
-        self.format_decimal = DecimalFormatModule(self)
-
-        #: A :class:`.QueryShell` instance.
         self.query_shell = QueryShell(self)
 
-        #: A :class:`.AccountDict` module - details about the accounts.
-        self.accounts = AccountDict(self)
-
         self.watcher = WatchfilesWatcher() if not poll_watcher else Watcher()
 
         self.load_file()

src/fava/core/filters.py

@@ -437,7 +437,7 @@ def __init__(self, value: str) -> None:
             tokens = LEXER.lex(value)
             self._include = PARSE(
                 lexer="NONE",
-                tokenfunc=lambda toks=tokens: next(toks, None),
+                tokenfunc=lambda toks=tokens: next(toks, None),  # ty:ignore[invalid-argument-type]
             )
         except FilterError as exception:
             exception.message += value

src/fava/core/query_shell.py

@@ -127,9 +127,9 @@ def noop(self, _: T) -> None:
         print(self.noop.__doc__, file=self.outfile)
 
     on_Reload = noop  # noqa: N815
-    do_exit = noop
+    do_exit = noop  # ty:ignore[invalid-method-override]
     do_quit = noop
-    do_EOF = noop  # noqa: N815
+    do_EOF = noop  # noqa: N815  # ty:ignore[invalid-method-override]
 
     def on_Select(self, statement: str) -> Cursor:  # noqa: D102, N802
         return self.context.execute(statement)

src/fava/ext/__init__.py

@@ -219,14 +219,14 @@ def decorator(
         func: Callable[[T], Response],
     ) -> Callable[[T], Response]:
         f: Any = func
-        f.endpoint_key = (
-            endpoint_name or func.__name__,
+        f.endpoint_key = (  # ty:ignore[unresolved-attribute]
+            endpoint_name or func.__name__,  # ty:ignore[unresolved-attribute]
             methods or ["GET"],
         )
         return func
 
     return (
-        decorator(func_or_endpoint_name)
+        decorator(func_or_endpoint_name)  # ty:ignore[invalid-argument-type]
         if callable(func_or_endpoint_name)
         else decorator
     )

src/fava/ext/auto_commit.py

@@ -24,17 +24,17 @@ def _run(self, args: list[str]) -> None:
         cwd = Path(self.ledger.beancount_file_path).parent
         call(args, cwd=cwd, stdout=DEVNULL)
 
-    def after_write_source(self, path: str, _source: str) -> None:
+    def after_write_source(self, path: str, source: str) -> None:  # noqa: ARG002
         """Add changed file to git and commit."""
         message = "autocommit: file saved"
         self._run(["git", "add", path])
         self._run(["git", "commit", "-m", message])
 
     def after_insert_metadata(
         self,
-        _entry: Directive,
-        _key: str,
-        _value: str,
+        entry: Directive,  # noqa: ARG002
+        key: str,  # noqa: ARG002
+        value: str,  # noqa: ARG002
     ) -> None:
         """Commit all changes on `after_insert_metadata`."""
         message = "autocommit: metadata added"
@@ -50,7 +50,7 @@ def after_delete_entry(self, entry: Directive) -> None:
         message = f"autocommit: deleted entry on {entry.date}"
         self._run(["git", "commit", "-am", message])
 
-    def after_entry_modified(self, entry: Directive, _new_lines: str) -> None:
+    def after_entry_modified(self, entry: Directive, new_lines: str) -> None:  # noqa: ARG002
         """Commit all changes on `after_entry_modified`."""
         message = f"autocommit: modified entry on {entry.date}"
         self._run(["git", "commit", "-am", message])