`MessageIDHeader` does not trim whitespace
Open
Nobody has claimed this yet.
stdlib
topic-email
type-bug
- Dominant language
- Python
- Stars
- 77.2k
- Forks
- 35.9k
- PR merge metrics
- PR metrics pending
Description
Bug report
Bug description:
I'm seeing many emails with headers broken across multiple lines. When this happens to Message-Id, the parsed header value will include a leading space:
eml = dedent("""\
From: "Foo Bar" <foo@bar.com>
To: Baz Baq <baz@baq.com>
Date: Thu, 22 May 2025 16:15:44 +0000
Message-ID:
<BY5PR09MB5490557EF2B28EC8E707108FBF99A@BY5PR09MB5490.namprd09.prod.outlook.com>
Content-Type: text/plain
Hello
""")
msg = Parser(policy=default_policy).parsestr(eml)
print(f"|{msg['Message-ID']}|") # prints | <BY5PR09MB5490557EF2B28EC8E707108FBF99A@BY5PR09MB5490.namprd09.prod.outlook.com>|
CPython versions tested on:
3.11
Operating systems tested on:
Linux
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Search CPython's email parsing code for MessageIDHeader and trace how Parser with default_policy handles the folded Message-ID shown in the report. Add regression coverage for that example and verify the parsed value has no leading whitespace.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 50/100