xml.dom.pulldom DOMEventStream drops SAX events produced by parser.close()
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Description
Bug report
Bug description:
Issue
DOMEventStream.getEvent() silently drops SAX events that are produced when parser.close() is called at end-of-stream. When the stream is exhausted, getEvent() calls self.parser.close() and immediately returns None without checking whether close() generated new events. This causes END_ELEMENT and other trailing events to be lost when bufsize causes the final tag to be split across reads.
Reproducer
import io
from xml.dom.pulldom import parse
events = list(parse(io.BytesIO(b'<a></a>'), bufsize=2))
print([e for e, _ in events])
# ['START_DOCUMENT', 'START_ELEMENT'] — END_ELEMENT is missing
Iterating the DOMEventStream (via list()) internally calls getEvent(), which is where the bug lives.
CPython versions tested on:
CPython main branch
Operating systems tested on:
No response
Linked PRs
- gh-145262
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
Start with DOMEventStream.getEvent(), where the issue says parser.close() can produce events that are not checked. Run the provided BytesIO reproducer with bufsize=2 and verify that iteration retains the trailing END_ELEMENT event; linked PR gh-145262 indicates the work is already underway.
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
- 25/100