Reduce type: ignore comments from 26 to 14

Replace suppressions with proper fixes where possible:
- Use isinstance checks instead of hasattr for type narrowing
- Use assert for None-safety where input guarantees non-None
- Access self._data directly instead of getattr
- Remove redundant to_unicode calls on already-str values
- Use explicit if/else instead of tricky and/or expressions
- Use dict[] instead of .get() where key is guaranteed present

Remaining 14 ignores are genuine mypy limitations: vendored dkim
API, private stdlib attrs, intentional method overrides, and
decorator typing.

Author: lavr

emails/backend/smtp/backend.py

@@ -50,7 +50,7 @@ def __init__(self, ssl: bool = False, fail_silently: bool = True,
         self.smtp_cls_kwargs = kwargs
 
         self.host: str | None = kwargs.get('host')
-        self.port: int = kwargs.get('port')  # type: ignore[assignment]
+        self.port: int = kwargs['port']  # always set as int two lines above
         self.fail_silently = fail_silently
         self.mail_options = mail_options or []
 

emails/signers.py

@@ -58,7 +58,9 @@ def get_sign_header(self, message: bytes) -> tuple[str, str] | None:
         # pydkim returns string, so we should split
         s = self.get_sign_string(message)
         if s:
-            (header, value) = to_native(s).split(': ', 1)  # type: ignore[union-attr]
+            native = to_native(s)
+            assert native is not None  # s is bytes, to_native always returns str
+            (header, value) = native.split(': ', 1)
             if value.endswith("\r\n"):
                 value = value[:-2]
             return header, value
@@ -73,7 +75,9 @@ def sign_message(self, msg: MIMEMultipart) -> MIMEMultipart:
         # but py3 smtplib requires str to send DATA command (#
         # so we have to convert msg.as_string
 
-        dkim_header = self.get_sign_header(to_bytes(msg.as_string()))  # type: ignore[arg-type]
+        msg_bytes = to_bytes(msg.as_string())
+        assert msg_bytes is not None
+        dkim_header = self.get_sign_header(msg_bytes)
         if dkim_header:
             msg._headers.insert(0, dkim_header)  # type: ignore[attr-defined]
         return msg
@@ -87,12 +91,20 @@ def sign_message_string(self, message_string: str) -> str:
         # but py3 smtplib requires str to send DATA command
         # so we have to convert message_string
 
-        s = self.get_sign_string(to_bytes(message_string))  # type: ignore[arg-type]
-        return s and to_native(s) + message_string or message_string  # type: ignore[operator]
+        msg_bytes = to_bytes(message_string)
+        assert msg_bytes is not None
+        s = self.get_sign_string(msg_bytes)
+        if s:
+            header = to_native(s)
+            assert header is not None
+            return header + message_string
+        return message_string
 
     def sign_message_bytes(self, message_bytes: bytes) -> bytes:
         """
         Insert DKIM header to message bytes
         """
         s = self.get_sign_bytes(message_bytes)
-        return s and to_bytes(s) + message_bytes or message_bytes  # type: ignore[operator]
+        if s:
+            return s + message_bytes
+        return message_bytes

emails/store/store.py

@@ -54,7 +54,7 @@ def remove(self, uri: BaseFile | str) -> None:
                 del self._filenames[filename]
             del self._files[uri]
 
-    def unique_filename(self, filename: str | None, uri: str | None = None) -> str:
+    def unique_filename(self, filename: str | None, uri: str | None = None) -> str | None:
 
         if filename in self._filenames:
             n = 1
@@ -66,9 +66,10 @@ def unique_filename(self, filename: str | None, uri: str | None = None) -> str:
                 if filename not in self._filenames:
                     break
 
-        self._filenames[filename] = uri  # type: ignore[index]
+        if filename is not None:
+            self._filenames[filename] = uri
 
-        return filename  # type: ignore[return-value]
+        return filename
 
     def add(self, value: BaseFile | dict[str, Any], replace: bool = False) -> BaseFile:
 

emails/utils.py

@@ -128,8 +128,9 @@ def get_fqdn(self) -> str:
 
 def decode_header(value: str | bytes, default: str = "utf-8", errors: str = 'strict') -> str:
     """Decode the specified header value"""
-    value = to_native(value, charset=default, errors=errors)  # type: ignore[assignment]
-    return "".join([to_unicode(text, charset or default, errors) for text, charset in decode_header_(value)])  # type: ignore[misc, arg-type]
+    native = to_native(value, charset=default, errors=errors)
+    assert native is not None  # to_native returns None only for None input
+    return "".join([to_unicode(text, charset or default, errors) for text, charset in decode_header_(native)])  # type: ignore[misc]
 
 
 class MessageID:
@@ -213,7 +214,7 @@ def parse_name_and_email(obj: str | tuple[str | None, str] | list[str],
 
 def sanitize_email(addr: str, encoding: str = 'ascii', parse: bool = False) -> str:
     if parse:
-        _, addr = parseaddr(to_unicode(addr))  # type: ignore[arg-type]
+        _, addr = parseaddr(addr)
     try:
         addr.encode('ascii')
     except UnicodeEncodeError:  # IDN
@@ -229,7 +230,7 @@ def sanitize_email(addr: str, encoding: str = 'ascii', parse: bool = False) -> s
 
 def sanitize_address(addr: str | tuple[str, str], encoding: str = 'ascii') -> str:
     if isinstance(addr, str):
-        addr = parseaddr(to_unicode(addr))  # type: ignore[arg-type]
+        addr = parseaddr(addr)
     nm, addr = addr
     # This try-except clause is needed on Python 3 < 3.2.4
     # http://bugs.python.org/issue14291
@@ -300,7 +301,7 @@ def fetch_url(url: str, valid_http_codes: tuple[int, ...] = (200, ),
 
 def encode_header(value: str | Any, charset: str = 'utf-8') -> str | Any:
     if isinstance(value, str):
-        value = to_unicode(value, charset=charset).rstrip()  # type: ignore[union-attr]
+        value = value.rstrip()
         _r = Header(value, charset)
         return str(_r)
     else: