importlib.metadata.metadata("package") fails with email.errors.HeaderParseError when README contains valid markdown link #119650
Description
Bug report
Bug description:
Here is a minimal example project (tested on Python 3.10):
pyproject.toml
[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"
[project]
name = "test"
readme = "README.md"
version = "0.1.0"
README.md
# Test
[MIT](<https://choosealicense.com/licenses/mit/>)test package:
__init__.py(empty)bug.py:import importlib.metadata; print(importlib.metadata.metadata("test"))
To reproduce:
pip install -e .
python test/bug.py
Traceback:
Traceback (most recent call last):
File "bug.py", line 1, in <module>
import importlib.metadata; print(importlib.metadata.metadata("test"))
File "lib/python3.10/email/message.py", line 135, in __str__
return self.as_string()
File "lib/python3.10/email/message.py", line 158, in as_string
g.flatten(self, unixfrom=unixfrom)
File "/home/mint/miniforge3/lib/python3.10/email/generator.py", line 116, in flatten
self._write(msg)
File "lib/python3.10/email/generator.py", line 199, in _write
self._write_headers(msg)
File "lib/python3.10/email/generator.py", line 226, in _write_headers
self.write(self.policy.fold(h, v))
File "lib/python3.10/email/_policybase.py", line 326, in fold
return self._fold(name, value, sanitize=True)
File "lib/python3.10/email/_policybase.py", line 369, in _fold
parts.append(h.encode(linesep=self.linesep, maxlinelen=maxlinelen))
File "lib/python3.10/email/header.py", line 389, in encode
raise HeaderParseError("header value appears to contain "
email.errors.HeaderParseError: header value appears to contain an embedded header: '# Test\n[MIT](<https://choosealicense.com/licenses/mit/>)'
It appears that [MIT] is seen as a header, as it would be in a TOML file. That's my best guess really. Any help is appreciated!
CPython versions tested on:
3.10
Operating systems tested on:
Linux