fix: add unicode and join multilines (#150)

* fix: add unicode and join multilines

Signed-off-by: Henry Schreiner <[email protected]>

* fix: custom email policy

Signed-off-by: Henry Schreiner <[email protected]>

* chore: reduce diff

Signed-off-by: Henry Schreiner <[email protected]>

* fix: typing

Signed-off-by: Henry Schreiner <[email protected]>

* refactor: EmailMessage -> Message

Signed-off-by: Henry Schreiner <[email protected]>

---------

Signed-off-by: Henry Schreiner <[email protected]>

pyproject_metadata/__init__.py

@@ -66,7 +66,6 @@
 __all__ = [
     'ConfigurationError',
     'ConfigurationWarning',
-    'RFC822Message',
     'License',
     'Readme',
     'StandardMetadata',
@@ -120,35 +119,29 @@ class ConfigurationWarning(UserWarning):
 @dataclasses.dataclass
 class _SmartMessageSetter:
     """
-    This provides a nice internal API for setting values in an RFC822Message to
+    This provides a nice internal API for setting values in an Message to
     reduce boilerplate.
 
     If a value is None, do nothing.
     If a value contains a newline, indent it (may produce a warning in the future).
     """
 
-    message: email.message.EmailMessage
+    message: email.message.Message
 
     def __setitem__(self, name: str, value: str | None) -> None:
         if not value:
             return
-        if '\n' in value:
-            msg = f'"{name}" should not be multiline; indenting to avoid breakage'
-            warnings.warn(msg, ConfigurationWarning, stacklevel=2)
-            value = value.replace('\n', '\n        ')
         self.message[name] = value
 
 
-class RFC822Message(email.message.EmailMessage):
-    """Python-flavored RFC 822 message implementation."""
+class MetadataPolicy(email.policy.Compat32):
+    def fold(self, name: str, value: str) -> str:
+        size = len(name) + 2
+        value = value.replace('\n', '\n' + ' ' * size)
+        return f'{name}: {value}\n'
 
-    __slots__ = ()
-
-    def __init__(self) -> None:
-        super().__init__(email.policy.compat32)
-
-    def __str__(self) -> str:
-        return bytes(self).decode('utf-8')
+    def fold_binary(self, name: str, value: str) -> bytes:
+        return self.fold(name, value).encode('utf-8')
 
 
 class DataFetcher:
@@ -618,14 +611,10 @@ def __setattr__(self, name: str, value: Any) -> None:
             self._update_dynamic(value)
         super().__setattr__(name, value)
 
-    def as_rfc822(self) -> RFC822Message:
-        message = RFC822Message()
-        self.write_to_rfc822(message)
-        return message
-
-    def write_to_rfc822(self, message: email.message.EmailMessage) -> None:  # noqa: C901
+    def as_rfc822(self) -> email.message.Message:  # noqa: C901
         self.validate(warn=False)
 
+        message = email.message.Message(policy=MetadataPolicy())
         smart_message = _SmartMessageSetter(message)
 
         smart_message['Metadata-Version'] = self.metadata_version
@@ -686,6 +675,8 @@ def write_to_rfc822(self, message: email.message.EmailMessage) -> None:  # noqa:
                     raise ConfigurationError(msg)
                 smart_message['Dynamic'] = field
 
+        return message
+
     def _name_list(self, people: list[tuple[str, str | None]]) -> str:
         return ', '.join(name for name, email_ in people if not email_)
 

tests/test_rfc822.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-import re
+import email.message
 import textwrap
 
 import pytest
@@ -32,6 +32,13 @@
             Foo2: Bar2
             """,
         ),
+        # Unicode
+        (
+            [
+                ('Foo', 'Unicøde'),
+            ],
+            'Foo: Unicøde\n',
+        ),
         # None
         (
             [
@@ -88,34 +95,31 @@
             """\
             ItemA: ValueA
             ItemB: ValueB1
-                    ValueB2
-                    ValueB3
+                   ValueB2
+                   ValueB3
             ItemC: ValueC
             """,
         ),
     ],
 )
 def test_headers(items: list[tuple[str, str]], data: str) -> None:
-    message = pyproject_metadata.RFC822Message()
+    message = email.message.Message(policy=pyproject_metadata.MetadataPolicy())
     smart_message = pyproject_metadata._SmartMessageSetter(message)
 
     for name, value in items:
-        if value and '\n' in value:
-            msg = '"ItemB" should not be multiline; indenting to avoid breakage'
-            with pytest.warns(
-                pyproject_metadata.ConfigurationWarning, match=re.escape(msg)
-            ):
-                smart_message[name] = value
-        else:
-            smart_message[name] = value
+        smart_message[name] = value
 
     data = textwrap.dedent(data) + '\n'
     assert str(message) == data
     assert bytes(message) == data.encode()
 
+    assert email.message_from_string(str(message)).items() == [
+        (a, '\n       '.join(b.splitlines())) for a, b in items if b is not None
+    ]
+
 
 def test_body() -> None:
-    message = pyproject_metadata.RFC822Message()
+    message = email.message.Message(policy=pyproject_metadata.MetadataPolicy())
 
     message['ItemA'] = 'ValueA'
     message['ItemB'] = 'ValueB'
@@ -134,7 +138,7 @@ def test_body() -> None:
         dolor id elementum. Ut bibendum nunc interdum neque interdum, vel tincidunt
         lacus blandit. Ut volutpat sollicitudin dapibus. Integer vitae lacinia ex, eget
         finibus nulla. Donec sit amet ante in neque pulvinar faucibus sed nec justo.
-        Fusce hendrerit massa libero, sit amet pulvinar magna tempor quis.
+        Fusce hendrerit massa libero, sit amet pulvinar magna tempor quis. ø
     """)
     )
 
@@ -155,9 +159,13 @@ def test_body() -> None:
         dolor id elementum. Ut bibendum nunc interdum neque interdum, vel tincidunt
         lacus blandit. Ut volutpat sollicitudin dapibus. Integer vitae lacinia ex, eget
         finibus nulla. Donec sit amet ante in neque pulvinar faucibus sed nec justo.
-        Fusce hendrerit massa libero, sit amet pulvinar magna tempor quis.
+        Fusce hendrerit massa libero, sit amet pulvinar magna tempor quis. ø
     """)
 
+    new_message = email.message_from_string(str(message))
+    assert new_message.items() == message.items()
+    assert new_message.get_payload() == message.get_payload()
+
 
 def test_convert_optional_dependencies() -> None:
     metadata = pyproject_metadata.StandardMetadata.from_pyproject(