ci: fix all ruff findings, enforce ruff, document the step

.github/workflows/test.yml

@@ -18,15 +18,13 @@ permissions:
 
 jobs:
   # ---------------------------------------------------------------------------
-  # Lint. rustfmt and mypy --strict are enforced (blocking); clippy and ruff
-  # stay advisory (continue-on-error) until their debt clears, and each runs
+  # Lint. rustfmt, mypy --strict, and ruff are enforced (blocking); clippy
+  # stays advisory (continue-on-error) until its debt clears, and each runs
   # regardless of the others:
   #   - rustfmt -> blocking (source is rustfmt-clean).
   #   - clippy  -> flip to blocking after the str->bytes fix (#19).
   #   - mypy    -> blocking: `mypy --strict fast_mail_parser/` is clean (#42).
-  #   - ruff    -> advisory: `ruff check .` reports issues in the package
-  #                stubs (UP006/UP007) and in test code (I001/E501/UP*). Fixing
-  #                those is out of scope here; flip to blocking once clean (#44).
+  #   - ruff    -> blocking: `ruff check .` is clean (config in ruff.toml).
   # ---------------------------------------------------------------------------
   lint:
     name: Lint
@@ -58,15 +56,12 @@ jobs:
           python -m pip install --upgrade pip mypy
           mypy --strict fast_mail_parser/
 
-      # Advisory: `ruff check .` currently reports issues in the package stubs
-      # (UP006/UP007) and in test code (I001/E501/UP015). Fixing those is out
-      # of scope; drop continue-on-error once they are resolved (#44).
+      # Blocking: `ruff check .` is clean (config in ruff.toml).
       - name: ruff check
         if: always()
         run: |
           python -m pip install ruff
           ruff check .
-        continue-on-error: true
 
   # ---------------------------------------------------------------------------
   # Supply-chain audit. Blocking (no continue-on-error): the dependency stack is

CONTRIBUTING.md

@@ -129,28 +129,31 @@ make benchmark
 The following checks are run in CI. Run them locally before opening a PR:
 
 ```bash
-cargo fmt --all -- --check       # Rust formatting (enforced / blocking in CI)
+cargo fmt --all -- --check       # Rust formatting (blocking in CI)
 cargo clippy --all-targets -- -D warnings -W clippy::cast_possible_truncation
-mypy fast_mail_parser/           # type-stub checking (advisory in CI)
-ruff check .                     # Python linting (advisory)
+mypy --strict fast_mail_parser/  # type-stub checking (blocking in CI)
+ruff check --fix .               # Python lint + autofix (blocking in CI; config in ruff.toml)
 ```
 
+Run **`ruff check --fix .`** before opening a PR — it auto-fixes most findings
+(import order, modern typing, etc.); fix any remainder by hand so `ruff check .`
+is clean.
+
 In CI:
 
-- **`cargo fmt --check`** is **blocking** — the source is rustfmt-clean and must
-  stay that way.
-- **`cargo clippy`** and **`mypy`** are currently **advisory**
-  (`continue-on-error`) while their remaining debt clears. Please keep new code
-  clean under both even though they do not yet fail the build.
-- `ruff` is advisory; keep Python code clean under it.
+- **`cargo fmt --check`**, **`mypy --strict`**, and **`ruff check`** are
+  **blocking** — keep the source clean under all three.
+- **`cargo clippy`** is currently **advisory** (`continue-on-error`) while its
+  remaining debt clears; please keep new code clean under it even though it does
+  not yet fail the build.
 
 ## Continuous integration
 
 The [`Test`](.github/workflows/test.yml) workflow gates every pull request. It
 consists of:
 
-- **Lint** — `cargo fmt --check` (blocking), plus `cargo clippy` and `mypy`
-  (advisory).
+- **Lint** — `cargo fmt --check`, `mypy --strict`, and `ruff check` (all
+  blocking), plus `cargo clippy` (advisory).
 - **cargo audit** — a **blocking** supply-chain audit of the Rust dependency
   stack (PyO3 0.29) against the RustSec advisory database. A new advisory
   against any dependency fails the build.

fast_mail_parser/__init__.py

@@ -1,4 +1,4 @@
-from .fast_mail_parser import parse_email, ParseError, PyMail, PyAttachment
+from .fast_mail_parser import ParseError, PyAttachment, PyMail, parse_email
 
 __all__ = [
     "parse_email",

fast_mail_parser/__init__.pyi

@@ -1,5 +1,3 @@
-import typing as t
-
 __all__ = [
     "parse_email",
     "PyMail",
@@ -18,11 +16,11 @@ class PyMail:
     def __init__(
         self,
         subject: str,
-        text_plain: t.List[str],
-        text_html: t.List[str],
+        text_plain: list[str],
+        text_html: list[str],
         date: str,
-        attachments: t.List[PyAttachment],
-        headers: t.Dict[str, str],
+        attachments: list[PyAttachment],
+        headers: dict[str, str],
     ) -> None:
         self.subject = subject
         self.text_plain = text_plain
@@ -36,7 +34,7 @@ class ParseError(Exception):
     """Error happened during parsing email."""
 
 
-def parse_email(payload: t.Union[str, bytes]) -> PyMail:
+def parse_email(payload: str | bytes) -> PyMail:
     """Parse raw content of email and return structured datatype.
 
     A missing ``Subject`` or ``Date`` header yields the empty string ``""``

tests/conftest.py

@@ -1,7 +1,8 @@
-import pytest
 import sys
 from typing import Callable
 
+import pytest
+
 from fast_mail_parser import PyMail, parse_email
 
 sys.path.pop(0)
@@ -10,7 +11,7 @@
 @pytest.fixture(scope='module')
 def read_mail() -> Callable:
     def wrap(path: str):
-        with open(path, 'r') as f:
+        with open(path) as f:
             return f.read()
 
     return wrap

tests/generate_rfc_corpus.py

@@ -16,8 +16,8 @@
 """
 
 import os
-from email.message import EmailMessage
 from email import policy
+from email.message import EmailMessage
 
 OUT_DIR = os.path.join(os.path.dirname(__file__), "data", "rfc")
 

tests/test_attachments.py

@@ -1,4 +1,3 @@
-import typing as t
 from fast_mail_parser import PyMail
 
 
@@ -7,13 +6,15 @@ def test__attachments_are_available(attachment_mail: PyMail):
 
 
 def test__base64_content_is_decoded(attachment_mail: PyMail):
-    attachment = list(filter(lambda a: a.mimetype == 'image/png', attachment_mail.attachments)).pop()
+    attachment = list(
+        filter(lambda a: a.mimetype == 'image/png', attachment_mail.attachments)
+    ).pop()
 
     assert attachment.content == b'PNG here'
 
 
 def test__expected_attachments_are_present(large_mail: PyMail):
-    expected_attachment_names: t.Set[str] = {'Lorem Ipsum - All the facts.pdf', 'Kitty Dark.png'}
+    expected_attachment_names: set[str] = {'Lorem Ipsum - All the facts.pdf', 'Kitty Dark.png'}
     attachments = [a for a in large_mail.attachments if a.filename in expected_attachment_names]
 
     assert len(attachments) == 2

tests/test_contract.py

@@ -11,7 +11,6 @@
 pass.
 """
 
-import typing as t
 
 import pytest
 
@@ -34,7 +33,7 @@
 MALFORMED_MESSAGE = " unexpected continuation\r\n\r\nbody"
 
 
-def _public_attrs(obj: object) -> t.Set[str]:
+def _public_attrs(obj: object) -> set[str]:
     return {name for name in dir(obj) if not name.startswith("_")}